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Plant Science Panel

Insecticides, biofuels, GMOs …

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'The Ugly Truth'

by Tracey Brown, director of Sense About Science

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Energy panel

Put your questions directly to researchers

The energy panel is a group of experts in energy and climate sciences. They are extending a standing invitation to answer your questions about energy generation.

There is widespread public interest in this field, and it sparks regular debate and controversies. But the science and engineering looking at the relative significance of technologies and the future of energy is often missing from these public discussions.

The energy panel uses a frank, public-led, expert-fed approach to help cut through polarised debates and conflicting information. Just like our plant science panel, our energy panellists from leading research institutes and learned societies have come together and made themselves available to take questions directly from you. You can read more about the energy panel members here.

Send in your questions using this form. You can also ask on Twitter (using @senseaboutsci and #energypanel) and on Facebook, or you can email us at energy@senseaboutscience.org.

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Our partners include the Institute of Physics, the National Nuclear Laboratory, the University of Manchester and the University of Manchester Dalton Institute. If your organisation is interested in partnering the energy panel then please get in touch.

Answers to your questions below

Dr. Luke Myers
“Which is more effective: developing & improving renewable energy sources, or decreasing demand?"
Sheena
26/08/2016
Dr Luke Myers

"l'll answer in terms of carbon intensity (the amount of carbon emitted for every unit of energy produced). You can see live UK carbon intensity and by generator type here (http://www.gridcarbon.uk) and see renewables emit zero carbon. Both decreasing demand and increasing renewables will reduce the carbon intensity but at present decreasing demand will be more effective as we can use the most carbon intensive generators (coal) less. We actually turned off all coal-fired stations for a period in march 2016 and since then they have generated less electricity than wind."

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Professor Zoe Shipton
“The UK's geology is more heavily faulted than that of the US. How does this make fracking more expensive in the UK?”
Faye Barlow
08/07/2016
Professor Zoe Shipton

"It depends on which bit of the UK or US you are talking about! Some parts of the UK and some parts of the US have lots of faults, while other parts have hardly any. The shale basins in the UK are, on average, more faulted than US basins. However, the density of faults (the number of faults in a given area) varies in both countries, so we shouldn’t generalise too much.

Faulting could make extraction more expensive for the same reasons that it does when coal mining – because the productive layer you are after is shifted up, down or sideways by fault movement. Miners working a coal seam would cut through a fault, find that the seam wasn't in the same position on the other side and have to work out from the geology where the seam had gone.

In modern mining or shale gas extraction it is possible to use geophysical techniques (3D seismic data) to image the rock layers of interest so you know in which direction - and by how much distance - the rocks may have been moved by a fault. But it’s not always easy to distinguish between shale layers that are gas-rich or gas-poor on these images. Modern drilling techniques include ‘logging–while–drilling’ tools that send data on the rock while it is being drilled. This gives real-time information on whether the well is being drilled in gas-rich shale layers or not.

All of this uncertainty could add to the length of time it takes to drill the well. In drilling, time is money, so if the borehole takes longer to drill then costs increase.

Finally, if the operator includes a standoff distance either side of a fault (because of concerns about earthquakes or flooding), then some gas-rich rocks won’t be accessible at all. This means the operators won’t produce gas from the whole well length, reducing profit."

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Professor Robert Steinberger-Wilckens
“Is renewable energy a reliable alternative to fossil fuel use in the U.K considering its dependency on climatic factors and the U.K.'s unsuitability for solar energy?”
James
09/06/2016
Professor Robert Steinberger-Wilckens

"Weather forecasting allows wind and solar energy to be predicted quite accurately. This is similar to the procedures used in predicting the amount of energy required from power stations. Once a forecast for the next 24 hours is made, this can be used to schedule which power stations are started up or not. Storage is still needed in case these predictions aren’t completely accurate (error of 3 to 5%), to allow gas turbines and other fossil fuel plants to deliver backup in due time.

Fortunately, solar and wind energy are rarely in synch and complement each other most of the time. If wave energy is added to the equation, electricity production becomes even more evenly spread. Biomass energy can be stored anyhow, and is just as reliable as any fossil energy source and can be used for backup. There is nothing to prevent us from imagining a very high contribution from renewable energies - we just need to learn to adjust nature a little more."

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Professor Laurence Stamford
"How much energy is used in the manufacture of a solar PV panel, and how does this convert into CO2-equivalent emissions? How long will it take the panel to 'repay' this carbon dioxide by generating renewable electricity once it goes into operation?"
Peter Eckersley
12/02/2016
Professor Laurence Stamford

"The manufacturing process for a single photovoltaic (PV) panel requires between about 8 and 60 kilowatt-hour (kWh). It varies a lot depending on the type of panel. However, I believe the question refers to the total life cycle, so we should also include things like mining, processing, transport, installation, as well as the equivalent stages for the rest of the system (the inverter, mounting brackets, wiring). Adding up all of that you come to roughly 700 kWh per panel. So, in a typical UK installation, the energy payback period would be 4-6 years (less in a sunnier country). In terms of carbon footprint, it’s 20-90 g CO2-eq./kWh, which stands for the grammes of carbon dioxide equivalent per kWh, i.e. it’s the carbon footprint (or global warming potential) per unit of electricity generated. This figure is probably 40-50 g for a typical modern system. Again, that’s in the UK. The value would be roughly half of that in a sunny country like Spain."

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Dr Luke Myers
"Don't they have to shut down turbines in gale force winds, to avoid damage?" - Question in response to this article

Erlanger
03/01/2016
Dr Luke Myers

"The cut-out wind speed varies slightly between different manufacturers and turbine design but is in the region of 25 metres per second or 56 miles per hour (mph). However this is for a sustained speed usually over a few minutes. For many turbines, the rotor blades turn at different rates depending upon the wind speed. This allows them to absorb energy from short term gusts well in excess of 56 mph. So only in the strongest storms or gales will turbines shut down."

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Dr Laurence Stamford
"Why not put solar panels on the roofs of all land based new builds and for that matter existing builds, even communal buildings, in fact anything with a roof on it?" - Question in response to this article

Haggala
03/01/2016
Dr Laurence Stamford

"We could certainly do that, but there would be a few drawbacks (for now at least). Firstly, cost: the price of houses and buildings would rise. Secondly, suitability: not all buildings are south-facing for maximum electricity generation, some might be shaded, etc.. And thirdly, grid management: when the sun goes down, there's no solar output, and unfortunately this often happens during peak electricity demand in the evening when people get home from work. So very suddenly you need to generate huge amounts of power to replace the solar output that just disappeared, which is technologically difficult.

Ignoring commercial buildings and flats, there are about 19 million houses in the UK. If we installed solar on every one, we’d have about 60 GW of solar capacity: with current technology we’d struggle to handle that much without vast amounts of storage. This is less of a problem for countries with lots of fast-response generation, like hydropower, and countries like the UK can eventually get around the problem too, but we're not quite there yet."

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Dr Niall Mac Dowell
"Former coal fired stations are now fed by imported Wood Chips. How much energy (CO2 emission) is created by the need to transport this resource?" - Question in response to this article

ToyToy
14/12/2015
Dr Niall Mac Dowell

"This is one of those “how long is a piece of string” questions. It really depends on what kind of biomass, grown where and how (fertilisers, pesticides etc.), how was it harvested, how was it processed into fuel, how far the fuel processing plant is from the power plant and how the biomass is transported to the power plant (road, rail, sea). The main contributors to CO2 emissions in this value chain are the biomass drying and transport, with how much fertiliser you use getting honourable mention as well. This underscores the importance of ensuring that these supply chains are supplied with low carbon heat, power and transport fuel as far as possible. However, emissions from the supply chain are small, relative to the whole system, comprising 1-3% of total CO2 emissions in the bioenergy-CCS supply chain."

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Professor Colin Snape
"Very narrow view, closing the coal powered stations. Why not convert them to run cleanly, or build new ones that burn their own nasty emissions?" - Question in response to this article

Pig Sick
18/11/2015
Professor Colin Snape

"The long-term solution for continuing to use fossil fuels for power generation is carbon capture and storage. Here the CO2 emissions are captured and then transported for permanent storage underground in geological formations, including depleted oil and gas reservoirs. However, it will be another 10 years before the technology is commercially demonstrated. The technology would only be applied to new coal-fired power stations which operate at much higher efficiencies than the old ones which are all set for closure in the UK by 2025."

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Professor Robert Steinberger-Wilckens
"Why isn't hydrogen being more extensively used than it is already?"
everhardus
11/11/2015
Professor Robert Steinberger-Wilckens

"Hydrogen is already being extensively used in industry, refineries, and space flight. Nevertheless, it is not publicy visible and future use may include many applications in the hands of consumers.

Using hydrogen with fuel cells for vehicles, electricity generators, heating etc. is still restrained by high cost, not of hydrogen, but of the fuel cells. Use of hydrogen causes zero to very low emissions. It offers considerable savings in cost of environmental and health damages. Of course this depends on the energy source used - but everyone today agrees that emission reductions can only result from using renwable energies in hydrogen production.

On the other hand, the lack of penalties for using fossil and polluting fuels makes hydrogen appear more expensive. Therefore it will remain difficult to use hydrogen economically as long as polluting fuels are effectively subsidised and artificially appear much cheaper than they are at a societal level."

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Professor Ian Cotton
"Why are the wheels falling off the British electricity generating system but this does not seem to be the case anywhere else in Europe?" - Question in response to this article

BetaMax
05/11/2015
Professor Ian Cotton

"Our electricity system is built around meeting peak demand, typically happening between 4pm and 6pm when people return home and turn on their TVs, ovens, heating etc. We need to have enough power stations to meet this demand and some that are kept in reserve if the ones in use fail. Last week, the size of this ‘safety net’ was too small following the breakdown of several coal power plants, leading to the National Grid asking for other generators to come online and for companies to reduce their demand.

We could build more power stations to increase the size of this safety net or we could continue to ask people to switch-off non-essential equipment at the time when demand peaks. As we get smart meters into houses that can automatically control your appliances, we are likely to make more use of this technique."

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Adrian Bull
"This Sunday last [1 Nov], I note that French Nuclear was generating 105% of demand ie exporting. If France can do it why can't we?" - Question in response to this article

Artusov
02/11/2015
Adrian Bull

"All countries regularly have more generation capacity than is needed to meet demand. Typically this occurs overnight or at the weekend when demand is lower than usual. The ability to export significant amounts of power when this happens depends on the connectivity of the country to its neighbours. As an island, the UK has limited interconnectivity – mainly via a few undersea cables to France and Holland. France, on the other hand, has land boundaries with many European neighbours and can export much more surplus power via grid lines which cross national borders."

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Professor Alison Smith
"Weren't "development" experts touting biofuels as a more environmentally sustainable source of energy just a couple years back?"
kjjng1
26/10/2015
Professor Alison Smith

"Yes, we need to diversify our energy sources to reduce our reliance on fossil fuels. Solar energy is an important part of that mix - one hour’s worth of solar radiation can account for the current world energy needs for a whole year. Photosynthesis by plants is one way to capture solar radiation, and fix atmospheric CO2 into plant biomass, which can then be used for biofuels. But to obtain the energy, CO2 is released again. So although biofuels can theoretically be carbon-neutral, some energy is used by us to grow the plants, and to harvest and process them to biofuels. For this to be truly sustainable it is important to take all these factors into account when comparing different forms of renewable energy.

First generation biofuels (i.e. ethanol from corn, biodiesel from rapeseed or palm oil) benefit from well-established agricultural practices in terms of productivity (and therefore cost), but care must be taken to avoid indirect land use change (iLUC) such as removal of forest to make way for plantations. There may also be unintended economic consequences leading to an increase in food prices, since first generation biofuels use the edible parts of plants. Second generation biofuels are trying to reduce the impact of both iLUC and competition with food crops by using alternatives, such as the non-edible, woody parts of plants, agricultural or municipal waste, or algae."

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Colin Axon
"Wouldn't you think that the member countries of the IEA have scientists advising them on how to deal with a scientific body? Or do they only take advice from energy companies?" - Question in response to this article

CanadaChuck
24/10/2015
Colin Axon

"Most governments directly employ an official scientific advisory service whose role is to offer an impartial view of evidence, or to report on developments across all scientific and technical topics. This advisory service will consult academic experts. Usually this service reports to elected (or appointed) Ministers of State (or similar) who make decisions on behalf of the nation. These Ministers may take additional information from the business sector, other elected politicians, and NGOs (or other pressure groups). The decisions made will reflect the political stance of the Government. Most governments have clear rules about declaring meetings between Ministers and those representing companies and pressure groups."

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Dr Niall Mac Dowell
"Are you encouraged or discouraged by update on progress or lack of it at Kemper County Missouri?

Obvious constraints and caveats apply to the CCS related economics at the US site. And 65% lower carbon emissions? What should we be attempting for the UK? Is this to secure future fuel sources for power generation or to mitigate CO2 emission from inevitable continuing use of coal?"

Philip Harris
23/10/2015
Dr Niall Mac Dowell

"I’m afraid I’m not terribly well informed about the Kemper County project. However, whilst it would obviously be fantastic to see this project already operating, the fact that the US and Korea are collaborating on this important project is encouraging in and of itself.

In the UK, the two projects in the Government’s Carbon Capture and Storage funding scheme are post-combustion CO2 capture and oxy-combustion (using oxygen instead of air to burn fuel) CO2 capture. This is important as we’re seeing a real build up in the number and diversity of projects around the world. To the final point, whilst the energy security point is a good one, I’d just note that the Peterhead project is a gas-fired power plant, so the focus is not just on coal."

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Dr Laurence Stamford
"How secure is coal as a future fuel in the UK?"

Philip Harris
23/10/2015
Dr Laurence Stamford

"An interesting question. Global coal reserves are very large: there’s potentially enough to last for hundreds of years. However, in the UK, we’re currently very reliant on imports. About 20% of coal is produced domestically and 80% is imported, mostly from Russia, Colombia and the USA (Russia’s been our main supplier for years). So strictly in terms of security of supply, we currently depend almost entirely on other countries, but the large global reserves mean that we should be able to find other suppliers if necessary.

The big problem is that coal is the worst energy source available in terms of its impacts on human health, climate change and ecosystems. Even if you burn coal with carbon capture and storage (CCS) you still have very high impacts for everything other than climate change."

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Professor Colin Snape
"Dr Niall MacDowell estimates the cost of CCS at around £100/MWh. Does this figure allow for the subsidies enjoyed by the fossil fuel industries? If not, what would be the true cost /MWh?" - Question in response to our Capturing Carbon live Q&A (Q15)

Peter Leach
23/10/2015
Professor Colin Snape

"The cost of electricity production with CCS quoted by Dr. MacDowell is the cost we expect to reach after the first demonstrations of CCS in the UK. Due to the risks involved, the demonstrations will receive some Government support which is the £1B currently under consideration for the first two demonstrations. After this, CCS will not receive any further subsidy. The current subsidies for oil and gas are aimed at extending operations in the North Sea with respect to the knock-on effect that this had on employment in places, such as Aberdeen. The true cost of electricity produced with CCS is projected to be close to £100 MWh after lessons have been learned from the first demonstration projects, both in the UK and globally. This is comparable to both nuclear and off-shore wind."

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Dr Laurence Stamford
"What are the pros/cons of fracking and what environmental /safety concerns do we need to address?"

Robert Heywood
23/10/2015
Dr Laurence Stamford

"Shale gas is a huge energy resource and could potentially reduce our use of coal and imports of liquefied natural gas, but on the other hand there are environmental questions surrounding things like the disposal of drilling waste and end-of-life well leaks. There’s also lively debate over whether we can afford to burn all that gas anyway given our carbon reduction targets (short answer: we would likely need carbon capture and storage). [Take a look at the Energy Panel Q&A on carbon capture & storage]

The industry and regulators are certainly learning from past mistakes. So we now have things like triple-cased wells (minimising the chance of underground leaks), reduced-emissions completions (minimising release of methane to the atmosphere), greater oversight of the chemicals in fracking fluid (which is normally ~99.5% water and sand) and real-time, remote monitoring of emissions."

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Dr Cecilia Fenech
"A recent article in the Daily Mirror described a pie and mash firm 'powered by a bio-refinery that converts its own leftover potatoes and potato peelings into electricity and steam'. Apart from potatoes, could other foods be used in this way?"
Daily Mirror
12/10/2015
Dr Cecilia Fenech

"A biorefinery is a facility that uses the energy in biomass to produce fuel, power and heat. A large number of foods can be used in such a way to generate electricity. The process usually involves anaerobic digestion, where food waste is converted into bioenergy, although other biorefinery configurations also exist. Within the UK a number of food waste anaerobic digestion facilities exist, while others use purposely grown crops (such as maize). How this process compares to other renewable energy options depends on a variety of factors, including what food you are using and what costs you are taking into consideration (for example, whether you are just taking into account the specific cost of the process or the cost of purposely growing crops as well)."

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"Will nuclear fusion ever be technically feasible? Are the barriers insurmountable?"
@Frostblade_
05/10/2015
Chris Warrick

"No-one pretends that the challenge of harnessing fusion power (essentially making a miniature sun on earth) is easy. But progress is being made and no challenge seems insurmountable. Nuclear fusion involves controlling a very hot gas or plasma - up to 150 million °C - with powerful magnetic fields in a device called a tokamak. This is challenging but is routinely being achieved at the Joint European Torus (JET) in Culham in Oxfordshire, UK. JET has decades of experience in remotely maintaining and upgrading the reactors and Culham is embarking on a programme to test new materials for future fusion power plants.

Yes, developing fusion is very difficult, but the world cannot afford to abandon it. Fusion power stations will one day offer millions of years of electricity, with fuels found in water and inherently safe operation. Fusion is truly the perfect energy source – and that is why we should pursue it."

Chris Warrick is head of the Communications Group at the Culham Centre for Fusion Energy

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Dr Laurence Stamford
"In a recent Daily Express article, Ross Clark claimed the following: 'Wind and solar energy are by nature intermittent. Neither will provide any electricity at all on calm, freezing evenings in winter when demand for electricity reaches a peak.' Any thoughts?"
Daily Express
24/09/2015
Dr Laurence Stamford

"Wind and solar are indeed variable. Over the past year, UK wind output has varied from <500 to 6400 MW, while solar varies from virtually zero to several thousand MW every day. National Grid of course recognise this and do not anticipate major problems until we are more reliant on wind and solar power. At that point, we will likely need extra ways to compensate for the day-to-day variation. This could involve storing wind and solar energy produced when conditions are more favourable (for instance using pumped storage) or the use of combustion plants (gas, coal or biomass) in tandem with these sources.

Demand management (through smart meters, for instance) could also allow us to shift certain energy consumption to times when we have more power available. Although this will affect large industrial consumers before it affects households, the long-term plan is that eventually our electricity meters will receive real-time data on electricity generation, and large appliances like fridges will then automatically modify their behaviour to shift their demand to more convenient times."

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Colin Axon
"Is ozone [at ground level] mostly from diesels, or are petrol engines also to blame? Will the low emissions zones planned/needed also reduce ozone amounts?" - Question in response to this article
EnviroCapitalist (online comment)
18/09/2015
Colin Axon

"Vehicles do not directly emit ozone at the tailpipe. The pollutants which both diesel and petrol vehicles emit react once in the surrounding air (using sunlight). The tailpipe emissions of a diesel vehicle will contribute less of the chemicals which lead to ground-level ozone than an identically sized petrol vehicle. But diesels are not blameless by any means. Low emission zones will help reduce all pollutants, especially particulates from diesel vehicles. However, the cleanest vehicle is one that is left at home!"

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Dr Niall Mac Dowell
"Given that methane constitutes less than 2 parts per million (ppm) in the atmosphere, are any attempts to capture such a rare molecule doomed to fail?”
Online comment
09/09/2015
Dr Niall Mac Dowell

"This question has a very simple answer – 'yes'. The suggestion of using any material to capture methane from the atmosphere is inherently problematic. To put this in perspective, the atmospheric concentration of carbon dioxide is ~400 ppm, and directly extracting carbon dioxide from the air is widely considered to be the most costly and challenging method of capturing this molecule. Importantly, as the concentration of a molecule in the atmosphere decreases, the work (and cost) required to separate the gas increases exponentially, and the concentration of methane is ~200 times lower than that of carbon dioxide."

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Solar Panel
"Is nuclear fusion really practically achievable?”
@Frostblade_
20/08/2015
Prof Steven Cowley

"This is the billion dollar question. We have done fusion on JET - 16 million watts of fusion power. In that sense we know we can do it. Next we must make a fusion “burn” - which means a self-sustaining fusion system. We hope ITER will do that and I am confident it will in the next decade. But the goal is commercial fusion power and for that we will need some smart engineering to bring down the cost. I hope that is possible by the mid century but this is far less certain."

Professor Steven Cowley is director of Culham Centre for Fusion Energy and CEO of the UK Atomic Energy Authority

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Laurence Stamford
"Is there sufficient uranium in the world for the "foreseeable future" say the next 50 years?"
@HStiles1
20/08/2015
Dr Laurence Stamford

Yes. With the type of nuclear reactors that we currently use (light water reactors), there’s enough for about 80-100 years at today’s consumption rates. There’s actually much more than that, but as we deplete reserves we need to access harder-to-reach sources, so it becomes more expensive. However, if we were to use a different type of reactor altogether (e.g. fast breeders) we would have enough for 30,000 years or more.

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Dr John Roberts
"After 40 years is nuclear fuel really 1/1000th its original radioactivity?" - as claimed here
Alex Thompson
20/08/2015
Dr John Roberts

There are two types (known as isotopes) of uranium found in nuclear fuel; uranium-238 (U-238) and uranium-235 (U-235). When the fuel is placed in a reactor it typically consists of 97% U-238 and 3% U-235. When the used fuel is removed it contains less uranium and now contains small amounts of “fission products”; such as strontium-90 and krypton-92, due to the uranium atoms splitting when they release energy.

The level of radioactivity is determined by the half-life, or time for the material to decay. Materials with long half-lives emit lower levels of radiation, whereas materials with short half-lives have high levels of radiation. The half-life of U-238 and U-235 is very long, over 700 million years, meaning uranium is not a major contributor to the radioactivity of the used fuel.

However the “fission products” have short half-lives of 30 years or less, some are even minutes or seconds. Therefore, they have high levels of radioactivity but also will decay significantly, to about 0.1%, over a 40 year period; meaning that the radioactivity of the nuclear waste is significantly reduced.

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Laura Grant
"[with] water already a scarce commodity. Where will all the extra water come from needed for fracking? & How to dispose[of it safely]?"
@powyswinds
13/08/2015
Laura Grant

Laura Grant is a policy adviser at the Chartered Institute of Water and Environmental Management (CIWEM), who published an independent report into "Shale Gas and Water

“The water required for use in hydraulic fracturing operations may come directly from the environment from a river or groundwater source, or it may be purchased from a water supply company. In both cases the Environment Agency sets the overall limit of water that can be taken through a system of licences. Other options include using seawater or reusing water from previous operations.

Disposal may require onsite pre-treatment before transportation to a specialist treatment plant or wastewater treatment plant for a range of treatment processes. The contamination profile will determine where the waste can be taken and how it will be treated. Both water sourcing and waste treatment are controlled by a system of permits.

So the main point is that both of these issues are considered by the regulators so the industry can’t run wild as it were.”

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Prof Michael Bradshaw
"Given that the consensus is for rapid reduction in fossil fuel use, what is the justification for opening up new locations of fossil fuel extraction, such as fracking?"
11/08/2015
Prof Michael Bradshaw

“While it is true that we need to significantly reduce fossil fuel use to avoid catastrophic climate change, this transition will take decades and the scenarios that do constrain global warming to two degrees still see significant fossil fuel use in the coming decades.

It is important to constrain coal use and converting from coal-fired power generation to gas significantly reduces emissions. Thus, many see gas as a bridge to a low carbon future. In the UK we are some way across this bridge, but all the forecasts suggest that we will need significant amounts of gas through the 2020s and beyond. At present over 80 percent of households in the UK use gas for heating. The question is whether or not some of that future gas demand should/can be met by UK shale gas.

Those who support its development say it will bring greater benefit than paying to import it from elsewhere - Norway, Qatar etc. - and that the environmental impacts can be managed. Those who are against it say we don't need the gas, which personally I don't think is the case, and that the environmental and social impacts are too great.”

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Solar Panel
"Perovskite solar cells are cheaper to manufacture but are they likely to become more efficient than silicon?”
Chris Worsfold
10/08/2015
Dr Luke Myers

"It is estimated the maximum efficiency of perovskite solar cells is 31% which is below that of traditional solar cells made from silicon. However, the key to solar energy is reducing the cost per unit of electricity generated. Perovskite cells are cheaper to manufacture and this is likely to reduce further as the technology becomes more established. The largest challenge this type of cell faces is the fact they degrade rapidly so research is required to make them last longer, then they will be a viable alternative to silicon and amorphous silicon (thin film) technologies"

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Chris Goodall
"I remember reading not long ago about a breakthrough aluminium-based battery. What has happened on that front?" - Question in response to this article
Rainborough (online comment)
09/08/2015
Chris Goodall

There are many different types of rechargeable batteries under development. The lithium battery is most advanced and forms the basis of most small scale storage systems, such as in phones, laptops and electric cars.

However there is no reason to believe lithium will be the dominant metal in a decade’s time. Aluminium is being investigated as are sodium and zinc. Other battery types, such as flow batteries, may use vanadium or other chemical elements. Each different technology is at a different stage of development and what seems to work in a lab may not be easy to manufacture in large quantities. A problem researchers often find is performance degrades after a small number of charging and discharging cycles.

Aluminium batteries look promising but, like other types, have to go through a prolonged period of research, development and then commercial testing before they reach the marketplace. The good news is batteries will get cheaper, more powerful and will recharge more quickly. However we just don’t know which battery chemistry will eventually come out top in a decade’s time. Anybody who says anything different is probably trying to sell something.

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Dr John Roberts
“The majority of the public do not want nuclear plants either-they can never be truly risk free…” - Question in response to this article
Valerie Wilkinson
09/08/2015
Dr John Roberts

I'm not sure whether this is actually the case in the UK and would be interested to see some evidence on this.

There are risks associated with all sorts of activities and they need to be managed in a cost appropriate way. Some people may argue that the costs associated with nuclear electricity are increased to an unacceptable level due to the management of the risks.

The opposite point of view would be that nuclear electricity could be cheaper if the safety systems where more proportionate to the actual risk, not the perceived risk. Risks change though, so some level of redundancy will always be required.

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Colin Axon
”Why not make the batteries the property of the distribution company, and just design cars so you can slot one out and a recharged one in at any petrol station in minutes? Use the same business model as domestic LPG gas containers.” - Question in response to this article
pinkCadilac (online comment)
09/08/2015
Colin Axon

Indeed this is one of many possible business models proposed, each with positives and negatives. Being able exchange a battery will be more costly to the consumer compared with the simplicity of plugging in a cable to recharge. Whereas a battery designed to remain in the vehicle will be cheaper to manufacture and maintain as will the vehicle itself.”

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Solar Panel
"[Is it possible that] tidal energy is [not renewable], sucking kinetic energy out of earth's rotation meaning the earth will rotate slower and the days will get longer?”

Alzie (online comment)
05/08/2015
Dr Luke Myers

"Enormous amounts of energy are already “lost” in the tides due to friction when the seas are squeezed through narrow and shallow areas such as the UK continental shelf. Which actually means that our days are getting longer! However the rate of change is infinitesimally small. It will take millions of years to notice any change. Adding in tidal energy (even what we think is a huge amount) will not make any measurable difference to this."

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Dr John Roberts
"Left-wing / green opposition to nuclear power based on out-dated views? Is new tech safer?"
@gezblair
30/07/2015
Dr John Roberts

“When discussing nuclear energy in the 21st century we are much more aware of the climate changes due to carbon emissions than we were in the last century. This needs to be taken into account when discussing the different ways that we produce electricity.

Coal and gas need to be phased out or we need significant investment in carbon capture technology. We could also choose to use less electricity, but it is a difficult option for the public to accept, and/or we should be using much more energy efficient devices. We need a non-intermittent low carbon form of electricity production. Currently only nuclear can provide this. We need significantly better technology if we are to rely on wind, solar and other forms of renewable energy.

On the safety issue, nuclear is already a very safe, the new reactors are safer than the old reactors. We should expect this just as we expect the cars that we drive to be safer than those of 50 years ago.”

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Dr Fiona Rayment
"Given the problems with marketing nuclear technology to most people, would it not be better to focus on those newer Molten Salt Reactor (MSR) designs that utilize spent nuclear fuel, so that it is marketed as more of a "recycling issue" (getting rid of that dangerous nuclear waste)? Oh, and it produces power too!"
Kevin Vaughan
29/07/2015
Dr Fiona Rayment “Waste is perceived to be an issue and causes some people to question the merits of nuclear power as a generating technology. It’s also true that decades of research have given us advanced designs, such as MSRs, which can generate less waste than conventional reactors or even use up some of the waste which we currently have. However these design concepts have not yet been put to the test on a commercial scale, nor have their economics been properly evaluated. As such it makes sense to stick with the proven conventional designs which are being planned in the near term, in addition to continuing research on advanced options for the future.”
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"The government are to cut solar panel subsidies. Isn’t a shift to solar and wind power essential and inevitable for a sustainable energy future and as part of our contribution towards reducing harmful fossil fuel emissions? Do you think this will affect the domestic FIT?"
@Patient__Wolf
27/07/2015
Dr Laurence Stamford and Prof AbuBakr Bahaj:

LS:"The idea behind subsidy is that it supports industries as they are developing, then is withdrawn when they are mature enough to support themselves. So it’s reasonable to cut subsidies eventually; the question is, when? On the one hand, solar and wind deployment has increased hugely in the last five years and too much too soon (particularly of solar) will cause grid management problems. On the other hand, solar is still nowhere near cost-competitive without subsidies so we need to be careful. Most importantly, investor confidence is fragile and cuts like this – particularly removing ‘grandfathering’ – make future investment more risky."

AB:"As you have suggested a shift to solar and wind power is imperative. Solar, wind and other renewable technologies are the future and we should invest more in their deployment as well as in research and development. However, these technologies will require a way to store the energy they produce as a way to overcome their intermittent nature. The sun isn’t always shining and the wind isn’t always blowing.

As the UK Government is currently reviewing its spending, so the domestic Feed-in-Tariff (the subsidy paid to people with solar panels on their homes) is also under threat. But the Energy and Climate Change Secretary of State Amber Rudd in a recent BBC interview indicated that she is not ruling out further subsidy for the solar industry. Obviously the UK Treasury is at the driving seat and the domestic Feed-in-Tariff may be reduced drastically or cut totally. Citizens should campaign against these cuts through their MPs and other media."

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Dr Niall Mac Dowell
"Squamish co claims to pull CO2 from air. Any uses for CO2? Can it be stored safely?"
@ibushfield
21/07/2015
Dr Niall Mac Dowell

"Direct air capture (DAC) is not new and is one of a number of technologies that come under the umbrella of greenhouse gas removal (GGR) or carbon dioxide removal (CDR) technologies. Relative to capturing CO2 from a power station’s exhaust gas, it takes a 4-5 times more work to pull CO2 from the air and hence is likely to be a very costly process. There are other technologies available for CO2 removal from the atmosphere – one of the most promising (but still controversial) options is BioEnergy CCS (BECCS) – this is the option that the IPCC (Intergovernmental Panel on Climate Change) models choose most often to provide the negative emissions that may be required.

Carbon Engineering want to split water into hydrogen and oxygen to make low carbon fuel but this process requires a LOT of renewable energy to produce the hydrogen, and thereafter even more to combine the hydrogen with the CO2.This kind of technology is often referred to as carbon capture and utilisation (CCU) and this typically requires large subsidies. It is also important to consider that if one has access to so much renewable energy, perhaps there are better things to do with it – remember that every time you convert energy from one form to another, there are efficiency losses!

The process of capturing CO2 from the air and combing it with wind-derived hydrogen to produce a fuel can require more energy into the system than can be produced from burning the fuel in the end. Furthermore using this ‘low carbon fuel’ just releases the CO2 back into the air…without any guarantees that you have actually displaced any fossil fuels. Therefore, from a climate perspective, if one wants to do the best thing for the environment, it would be much better to fund Carbon Capture and Storage (CCS) projects.

As for uses of captured CO2, the best use to which it can be put in the near term is geological sequestration where it can be stored extremely safely. It is true that we may one day need to remove CO2 from the atmosphere, if we overshoot our emissions targets owing to inaction on our part now. However, my view on this is that we really don’t want to find ourselves in this position, and that focusing on technologies like this could prove to be a dangerous distraction from the real task at hand – to act now and in a material way to prevent more fossil CO2 entering the atmosphere."

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Dr John Roberts
"I have yet to see a convincing argument against the use of Thorium Fission for CO2-free energy production, especially with the fail-safe molten-salt reactor design. Is there one?"
Terence Waites
20/07/2015
Dr John Roberts

“Thorium can be used as a fuel for low carbon electricity production, and utilised in molten salt reactors. The issue preventing it being done is commercial rather than technology. It would need significant investment to build the fuel fabrication facilities etc and the nuclear power plants. As it is currently an unproven fuel commercially, investment would be needed on research to verify the potential.

The big nuclear companies with experience of building and operating nuclear power plants have invested a lot of money demonstrating the viability of uranium based nuclear power plants, particularly the pressurized water and boiling water reactor variants. At this stage of the development cycle and with sufficient uranium reserves predicted there is no strong driver to change the technology.”

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Colin Axon
"How can we meet our future energy demands best? If wind is the most 'efficient' energy source then why don't we focus on that as a society? Why do some mention nuclear as a way forward and why do we use other sources of energy generation at all if wind is the most 'efficient'? Can it meet our energy demands now and in the future?"
Alasdair
17/07/2015
Colin Axon "Never put all of your eggs in one basket; security of supply comes from using a variety of fuel sources and conversion technologies. This spreads the risk of specialist materials and skills becoming unavailable. Although I do not favour using nuclear energy, wind alone is unlikely to meet all of the UK power demand (now or in the future) unless we reduce our total demand very significantly. Reducing demand and improving efficiency is the first and most effective thing to do."
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Chris Goodall
"What time of day should you charge your laptop and phone to have the lowest ecological impact? (in DE, ideally)"
@skyglowberlin
16/07/2015
Chris Goodall

"Firstly, laptops and phones are not major users of electricity. In the case of a laptop, charging it from empty will use less than boiling a kettle for a cup of tea. However most people would say 'during the night'. The logic is that in the UK the average carbon emissions per unit of electricity are historically at their lowest, largely because demand is low but the wind is still blowing and low carbon nuclear power is providing a relatively large fraction of total electricity. In my opinion, this logic is wrong and the average emissions per kilowatt hour aren't relevant. The important question is what are the emissions of the extra watt hours that need to be generated?

In the UK, the marginal generator in the summer is usually a gas-fired power station, at whatever time, day or night. So the marginal emissions don't change by time of day. In the winter, it is usually coal. But the same argument applies. In Germany, the situation is slightly different. Baseload demand is provided by lignite (the worst sort of fuel from a carbon point of view). Marginal generation comes usually from hard coal. So once again it doesn't matter when the charging is done.

There is possibly another answer: In simple terms the rule should be 'never charge your devices when overall electricity demand is highest'. In essence, this means avoiding between 4 and 7pm in the UK winter. In summer, demand peaks at around noon or around 8pm here. The argument for this rule is the long term benefit of minimising the maximum need for electricity production capacity. By holding down peak demand, you are cutting the profits made from fossil fuel generation and making it less likely that new plants will be built. But, as I say, this is a very difficult argument. Others will think differently."

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Colin Axon
"How efficient is wind power compared to other sources & any realistic alternative to nuclear in shorter term?"
@Alasdair_A_
10/07/2015
Colin Axon "Efficiency is a slippery term. Efficiency could mean electrical, mechanical, materials, or land use etc. And is this just whilst the device is operating or is it the whole cradle-to-grave lifecycle? We must always ask how was any quoted ‘efficiency’ figure arrived at? When the requirements of both systems for construction, fuel exploration and production, operation, decommissioning, and treatment of waste are accounted for, on almost all measures wind power is ‘more efficient’."
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Fracking
"Given that the consensus is for rapid reduction in fossil fuel use, what is the justification for opening up new locations of fossil fuel extraction, such as fracking?"
Felix Hewison-Carter
07/07/2015
Prof Michael Bradshaw

"While it is true that we need to significantly reduce fossil fuel use to avoid catastrophic climate change this transition will take decades and the scenarios that do constrain global warming to two degrees still see significant fossil fuel use in the coming decades. It is important that we constrain coal use and converting from coal-fired power generation to gas significantly reduces emissions. Thus, many see gas as a bridge to a low carbon future. In the UK we are some way across this bridge, but all the forecasts suggest that we will need significant amounts of gas through the 2020s and beyond. At present over 80 percent of households in the UK use gas for heating. The question is whether or not some of that future gas demand should/ can be met by UK shale gas. Those who support its development say that it will bring greater benefit than paying to import it from elsewhere such as Norway, Qatar etc. and that the environmental impacts can be managed. Those who are against it say we don't need the gas, which I don't think is the case, and that the environmental and social impacts are too great."

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Dr Niall Mac Dowell
"An article in the Financial Times reported on Shell bidding to invest in CCS. Will CCS cut greenhouse emissions? Greenpeace have argued that it will be increase oil extraction? And are there any dangers in storing CO2?"
03/07/2015
Dr Niall Mac Dowell

"Carbon capture and storage (CCS) technology has been used all over the world for decades and is not controversial. It will allow the capturing of CO2 emissions released from the burning of fossil fuels. Currently amine scrubbing (one option) is used for gas purification in the natural gas industry, another leading option, oxy-combustion, relies upon the separation of O2 from air– this technology is also used around the world on a very large scale. CCS is cost competitive when compared with renewables. It is the cheapest way to provide low carbon energy and is a technology available all the time. Wind and solar energies have variable outputs that depend on location, time of day etc and an additional plant (coal or gas) must be run too.

Shell are interested in investing in CCS as there is a market in the green growth area. Canada managed to open the world’s first large scale coal-fired power plant with CCS both on budget and on time. I’m actually given to understand that if they were to build the same facility again, it could be substantially cheaper – perhaps even as much as 30%, which is a fantastic improvement moving between the 1st and 2nd generation.

Greenpeace are referring to CO2-Enhanced Oil Recovery (CO2-EOR) where injected CO2 is used to recover oil from existing reserves. We continue to need oil and this method is much better than drilling new holes or using tar sands which both impact severely on the environment. It has also been utilised for decades in the U.S and is a safe method. It creates jobs, is good for business and allows oil prices to remain economically viable.

Storing CO2 in the ground poses no danger or safety concerns. Over time it dissolves in water then binds with rocks and is securely stored. It has actually recently been shown that if CO2 does leak, it doesn’t appear to do major damage to the sea floor…this is obviously not a desired outcome, but it’s good to know that it’s not the end of the world, if a leak does occur.

CCS is one way to continue using fossil fuels but prevent dangerous climate change effects whilst moving towards and developing sustainable options. While CCS is a fantastic technology it’s important to remember that it is not a silver bullet and a multitude of technologies must be used to solve our energy and climate change problems."

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Laurence Stamford
"It has been reported that Government subsidies for onshore windfarms will end a year earlier than previously proposed. Energy secretary Amber Rudd has been quoted as saying "By 2020 windfarms will provide 10% of the UK's energy needs". Is this feasible with subsidy cuts? Won't the wind industry be put off from building windfarms? Isn't this a step in the wrong direction for renewable energy? And will this produce a rise in fuel bills...?"
Article comments
22/06/2015
Dr Laurence Stamford

“Well firstly let’s be clear that we’re only talking about onshore wind here. If we include offshore, then we already have enough to provide about 10% of electricity this year. Offshore’s also the biggest growth area so, assuming offshore subsidies are safe, we’ll likely get about 20% of electricity from wind by 2020 anyway (onshore + offshore). There’s also some talk of protection for proposed onshore farms that already have planning approval (although this isn’t very clear yet): if true, that could take us to 25% by 2020. However, the key point here is that industry needs regulatory stability, so changing things unexpectedly is almost always a bad idea. Removing onshore wind’s Renewable Obligation early is likely bad for all energy investment, not just wind, because it suggests that all current schemes are fair game.”

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"Ben Webster the Environment Editor for The Times (£) has written today in an article "Extracting 10% of the gas trapped in rocks under the north of England would meet all of Britain's demand for the fuel for 40 years" Is this true?"
16/06/2015
Prof Quentin Fisher "We have currently virtually no knowledge of the amount of gas in place within shales below northern England and that is why it is so important to conduct more exploratory drilling. The figure quoted in the times is totally speculative."
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"It was reported that 'fracking will be fast tracked without public consent'. Is exploratory fracking really fracking? And are there any differences in risk between exploratory and normal fracking?"
15/06/2015
Prof Michael Bradshaw and Prof Quentin Fisher

MB: "The stage that the UK shale gas industry is at requires a programme of exploratory drilling and appraisal. Initially, this will probably mean drilling conventional wells to obtain rock samples and also the conduct of some hydraulic fracturing on a small scale to determine flow rates. Eventually, there will be horizontal drilling and high volume hydraulic fracturing to determine whether or not the shale resource is commercially viable. Estimates of the number of wells required differ, but the previous Government talked of 20-30 wells over a 2-3 year period. Without this activity we will never know if shale gas is economic to develop and it will also provide an opportunity to monitor the environmental impacts of shale gas development. If companies decided to move ahead with commercial development on a larger-scale they will need to apply for planning permission to do so."

QF:"Shale gas producers wouldn’t normally conduct an hydraulic fracture on an exploration well. They would normally drill an exploration well, take core and measure properties down the well bore before they decided whether to further appraise the reservoir. If they did decide to go ahead with an appraisal or pilot drilling program then they would hydraulically fracture well. Essentially, fracking is fracking, So hydraulically fracturing an appraisal well is the same as hydraulically fracturing a production well. However, industry faces different issues when fracking an appraisal well to a production well. For example, less will be known about the subsurface at the appraisal stage whereas in the production phase there is more pressure to reduce costs. Overall, I would argue that there is actually no difference in risk because potential dangers are taken into account when planning the hydraulic fracture stimulation and actions are taken to ensure that the public and environment are not put into danger as a result of their operations."

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Dr Laurence Stamford
"As reported in the Independent and the Guardian, Australian PM Tony Abbott has been quoted as saying "windfarms are noisy, visually awful and have potential health impacts". Are these comments based on evidence?"
12/06/2015
Dr Laurence Stamford: “The aesthetic argument against windfarms is of course completely subjective. It’s interesting to note that surveys show that opposition to windfarms decreases the closer you get to the windfarm, i.e. people who live close to farms and see them on a daily basis from their homes are, on average, strong supporters. As for the noise, of all the noise complaints received by local councils, virtually none are about wind turbines. I’d also suggest that the ‘health impacts’ are a red herring. Most of these claims are self-reported and completely lacking any scientific basis. There are real, demonstrably significant health impacts from phenomena we encounter every day (emissions from vehicles and fossil fuel power plants, smoking, etc.): these would be sensible things to focus on. Coming from Tony Abbott this is particularly perverse given the fact that about 70% of Australia’s electricity comes from coal power, the worst energy technology available in terms of human health impacts.”
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Colin Axon
Will the investment in renewable energy shrink if we choose nuclear power?
10/06/2015
Colin Axon

"There is no direct link, so it is very unlikely to have any effect. The stronger effect is the attractiveness (or otherwise) of the investment conditions for renewables in other countries. For the financing of any project it’s about trading-off the rate of return on the investment and the risk of not getting the capital back."

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Dr Fiona Rayment
It has been reported that the Government's austerity drive will reduce spending on the clean up of old nuclear reactors. Are there any safety issues in delaying decommissioning?
09/06/2015
Dr Fiona Rayment

"In many cases, delaying decommissioning can make the activity safer, rather than more dangerous. This is because radiation levels reduce naturally over a period of time, meaning lower exposure for workers when the work is carries out.

However the UK has a well-respected and very capable nuclear industry regulator (the Office for Nuclear Regulation) who will ensure that all work is carried out safely and that no hazard is posed to the public by the scheduling of decommissioning projects."

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Chris Goodall
"Greenpeace have stated that greenhouse emissions are falling faster in China than in any other country. Why has the fall been so dramatic and is this just a seasonal thing? Is it likely to increase with the growing number of coal power plants that China is currently constructing?"
15/05/2015
Chris Goodall

The fall in Chinese emissions is unequivocally good news. And, no, it is not a seasonal matter.

China has now largely constructed the infrastructure for a modern society. During the process of construction, coal demands (such as for kilning cement and making steel) were huge. Now building has slowed, so coal need has fallen sharply. We see this everywhere in countries which have reached advanced economic development.

Electricity demand is also growing much less strongly. Last year saw the slowest growth in more than a decade. This is partly because of rapidly slowing economic growth. However in many other countries, such as the UK, electricity demand is also falling sharply. Maybe Chinese electricity demand has not yet peaked but it is pretty close to a peak.

China is now (net) closing coal-fired power stations, announcing recently, for example, that all the plants supplying Beijing will shut soon.

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"People talk about fracking being used in the short and medium term. But building all this infrastructure for something that's only a 'transition fuel' is pretty short sited? How can we ensure we wean ourselves off fracked gas and onto renewables in the future?"
12/05/2015
Prof Michael Bradshaw

"We are not actually going to have to build that much infrastructure as we already have a well-developed national and local gas transmission system and the potential production areas are near to centres of gas demand. There will need to be some investment in local processing facilities and pipeline connections, but those costs will have to be covered by the developers. The other factor to consider is that the shale gas production profile is one of a rapid peak and decline, with a long tail of relatively low production. We are only starting to understand the consequences of this in the US, but it means that the majority of an individual well’s production happens in the first few years. This means that to keep production up it is necessary to keep drilling, but it also means that it is relatively easy to ‘switch off’ if prices fall, and then ‘switch on’ if they rise. This is what we are seeing with tight oil in the US at the movement. This could mean that we see are relatively short-lived shale gas window in the UK during the 2020s into the early 2030, that then falls away as gas demand falls in response to the UK’s decarbonisation strategy."

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"How much will #fracking cost in comparison to renewable #energy solutions to meet the UK's energy needs in the long term?"
12/05/2015
Prof Michael Bradshaw

"This is impossible to know at the moment for the simple reason that we don’t know the cost of commercial shale gas drilling in the UK. Until the industry has been able to drill and flow-test a well to get a sense of how much gas can be produced, they won’t be able to work out the commercial viability of shale gas in the UK. The costs will certainly be higher than in the US, but the UK gas price is also significantly higher than the US price. As to a comparison with renewables, the cost of solar has fallen significantly, as has onshore wind, but offshore wind is very expensive. Furthermore, the renewables sector benefits from subsidies, though these are also falling. The shale gas industry will benefit from some tax concessions, and those using gas to generate power could benefit from capacity payments, but less than the 30 per cent of the gas used in the UK goes into power generation. The bottom line is that a shale gas industry will only develop in the UK if it makes commercial sense and we are some way from knowing if it does."

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"Shouldn't we adopt a precautionary approach regarding fracking and instead look at the alternatives?"
12/05/2015
Prof Michael Bradshaw

"I would certainly agree that the previous government’s statement about ‘going all out for shale’ was ill judged. The Conservative Party’s manifesto makes it clear that the new Conservative Government will continue to promote shale gas development. The approach being adopted is risk based in the sense that the regulators (DECC and DEFRA) believe that the risks are well known and can be managed with existing regulations and the application of the best available technologies and practice. The problem is that without actually drilling in the UK we don’t have the evidence base to support such an approach. But, this leaves us in a catch-22 whereby we don’t know what the risks are, but there are those that say we can drill until we have the evidence to know what the risks are. I agree that a more precautionary approach where we have a monitored programme of exploratory drilling and appraisal, couple with baseline monitoring and real-time monitoring of impacts would make sense. In effect, that is what will happen should Cuadrilla get its planning permissions to drill as the government has give NERC/British Geological Survey £31 million to allow monitoring of drilling activity. On reflection, had the government followed this more precautionary approach from the start the current level of opposition may have been lower, but the majority still remain undecided."

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"With relation to your answer to question 23, Halliburton has been used to provide fracking fluids in Australia. BTEX chemicals have been used in fracking. Will Halliburton provide the fracking fluids in the UK?"

12/05/2015
Prof Quentin Fisher

"Chemicals will certainly be purchased from a very wide range of suppliers. I’m sure Halliburton will be a company that will submit tenders to supply a whole range of services to the fracking industry. Regulatory authorities, such as the environmental agency will assess the safety of chemicals used and the risks of them entering the environment. I find it rather odd that people get overly obsessed with what is being pumped so far underground that it has very little chance of polluting our environment yet are perfectly happy to allow the agriculture industry to spay a whole range of chemicals directly on to the food they eat."

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"To what extent is there evidence of fracking causing pollution issues? Should this be a worry for nearby residents?"
12/05/2015
Prof Quentin Fisher

"I think the main pollution issue is simply CO2 emissions in the atmosphere than come with burning CO2 for energy. We clearly need to move away from fossil fuel usage and fracking for gas should only be used as a bridging technology until renewables become more efficient. In terms of pollution caused by the fracking process, I think the development of shale gas in the UK will be slower than in the USA and we have tighter regulations so I don’t think residents should be overly concerned about pollution."

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"Fracking has been done in the past in this country, so why does so much controversy surround it now?"
James Clarke
12/05/2015
Prof Quentin Fisher

"Although fracking has been widely used in the UK the volumes of fluids and proponents pumped into the ground are far less than have been used on the onshore UK but are similar to what have been used offshore UK and widely onshore USA. However, I think there are two big causes of the current controversy. First, the film Gaslands, which is a widely inaccurate narrative of the environmental impacts of fracking has been taken on board by the general public as being factual. Secondly, green groups are quite rightly lobbying to cut carbon emissions and have targeted the shale gas industry. Instead of being honest and arguing the case that we should reduce emission they have instead used scaremongering (e.g. water contamination, earthquake risk, water usage etc) to increase protest from the general public in an attempt to reduce gas production."

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"Is the research in the US around earthquakes and increasing frequencies relevant to the geology of the UK?"
12/05/2015
Prof Zoe Shipton "Is the US experience relevant for the UK? Yes and no. Yes, because physics is physics and we can learn a lot about rock mechanics by studying the US earthquakes. No, because whether a given fault will slip during a frack job or not is dependent on 1) the stress in the vicinity of the fault (the orientation and magnitude of the geological forces on the fault), 2) the mechanical properties of the fault (a function of the rocks that the fault is cutting (question 19 ) and 3) how close the fault is to slipping. Ideally an operator would undertake a survey of the faults in the region of their wells, and measure the stresses down the hole. This would need to be done on a site by site basis as faults and stress are variable from site to site and this is now required in the Hydraulic Fracturing Plan part of the DECC guidance. Even without this requirement, operators measure down-hole stress anyway in order to design the most effective frack jobs – i.e. they need to know which direction the fracks are going to propagate (stress direction) and estimate the pressures they will need to use to frack (stress magnitude). Mapping faults is less straightforward, and I don't know if this is routinely done in the US, but the DECC guidance makes it a required part of getting permission to frack."
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Re question 24 "If "damage compromised the well beyond repair, that section of the well could be plugged and abandoned" - But then too late!"
@Refracktion
12/05/2015
Prof Zoe Shipton

"Damage to one segment of well casing or cement does not mean that there will be a pathway for methane or fracking fluids all the way to the surface. It is possible to run logging tools to image behind a well casing to check the integrity of the cement in the well."

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"Where the geology is so faulted, is fracking likely to give rise to depressurisation of any underground aquifers?"
Christine Stanton
12/05/2015
Prof Kevin Taylor

"Underground aquifers are not pressurised in the sense gas reservoirs are. Aquifer pressure is much lower and is controlled by hydraulic head pressures rather than from pressure derived from depth. Also, fracturing operations take place at depths much greater than freshwater aquifers are present at."

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"The chemicals that are pumped into the ground – what do they actually do? Are they meant to make getting the gas/oil out of the ground easier? How do they do that?"
Holly Childs
12/05/2015
Prof Kevin Taylor

"The chemicals are included for a number of purposes. These include viscosity enhancers (which is often Guar Gum) which help carry sand into fractures and keep them open. There are also chemicals to help the gas release from the pores in mineral and organic surfaces. Plus there are chemicals to stop biofilm (microorganisms that stick to surfaces) growing in the borehole that would otherwise block flow."

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"Isn't it true that most of the shale gas in the UK is actually inaccessible?"
James Perry
12/05/2015
Prof Kevin Taylor

"There is not a straightforward answer to this. By the very nature of gas reservoirs it will not be possible to access all of the gas, and the US experience suggests that more of the gas is inaccessible than accessible. The ratio of these two will depend on the geology of an area, advances in technology, and the economics of gas prices."

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"Afraid I'm going to sound naive here, what replaces the gas in those spaces where it is extracted from?"
Adie Fletcher @adiefletcher
12/05/2015
Prof Kevin Taylor

"In a sandstone – ie conventional – reservoir, the oil or gas would be replaced by water from below. In shale gas though, due to the very low permeability, water replacement is unlikely. What most likely happens is that the holes which were filled with gas (which are very small) will remain empty and undergo some compaction and deformation."

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"What are the limitations on land after a fracking site is abandoned"
@hagitw
12/05/2015
Prof Quentin Fisher

"There are no limitations on the land. The rocks from which the gas is taken is very stiff (strong) so unlike gas production from conventional gas reservoirs and/or coal mining there will be no subsidence issues. There is negligible infrastructure left after the wells have been drilled and fractured so even the land from where the wells are drilled could be used as normal when the equipment used for drilling and fracturing has been removed."

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"What resources are recommended to help the public understand #shalegas? We've recently published our own "
@EnergyInstitute
12/05/2015

GM: "I think we need a mix of things. Web-based information such as that posted by the Energy Institute and others is essential and getting more comprehensive and accessible. The industry could develop ‘roadshows’ that have demonstrations, models, and take experts to communities that have concerns and want to know more. Local panel discussion involving experts and those challenging the technology go a long way to getting the concerns out in the open and the evidence presented clearly in a local context. Getting programme makers interested in the topic would ensure reaching wide audiences.

Also there is too much parallel processing – some coordination between industry, the Department of Energy & Climate Change, the Office of Unconventional Gas and Oil, and NGOs would help to be more effective in making evidence-based material available, with FAQs having some attributable sources."

MB:"The problem is that most sites have a particular take for or against shale gas development in the UK. The Department of Energy and Climate Change has shale gas pages that provide lots of information. The British Geological Society has pages on its site that explain the geology in the UK and the nature of shale gas. The UK Onshore Operators Group’s site presents the industry’s view. They also sponsored the ‘Lets Talk About Shale’ site with lots of questions and answers. There is also Nick Grealy’s Not Hot Air site that is pro-development. There is an opposing ‘Talk Fracking’ site sponsored by various celebrities. ‘Drill or Drop’ purports to present an independent view, and The Shale Gas Task Force has its own site. The various NGOs also have pages on shale gas. There are also a huge number of sites in the US, but they are specific to operations there. In Europe there is the Shale Gas Information Platform (SHIP). I could go on, the point is that there are lots of sites; the problem is working out where they are coming from."

ZS:"I would direct people to the Royal Society and Royal Academy of Engineering Report , and the Scottish Government's Expert panel report . These were both written by panels of independent experts, and were peer reviewed. Both panels also contained environmental experts."

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"Does the panel agree that the risk from fracking-induced seismic activity routinely gets mischaracterised as being a low risk to roads and buildings, instead of an alarming risk to well integrity?"
John Hobson
12/05/2015
Prof Zoe Shipton

"I agree with the questioner that seismicity from fracking, or associated wastewater disposal (which would not be allowed in the UK or Europe), is a very low risk to roads and buildings. The risk of damage to a well is larger but still relatively low.

Remember that risk is likelihood of occurrence multiplied by the hazard. The likelihood of an earthquake related to fracking being felt at the surface is very very low: a handful of recorded events in millions of frack jobs to-date. The hazard is also low due to the rock mechanics: shale is a relatively flexible rock, so the magnitude is not likely to exceed 4. According to the British Geological survey this could be "Felt by many people, often up to tens of kilometres away; some dishes broken; pendulum clocks may stop." The likelihood of an effect on a well is therefore also very low, though the hazard is slightly greater. If an event damaged the well casing or cement it could affect the integrity at that point in the well. If that damage irreparably compromised the well, that section could be plugged and abandoned."

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"Which chemicals are used in fracking fluid?"
Ira
12/05/2015
Prof Quentin Fisher:

"Generally, water makes up 98 to 99.5% of fracking fluids. A wide range of chemicals can be added to water, but these vary so widely that it is difficult to make generalizations. Common chemicals added include gelling agents (e.g. guar gum); biocides e.g. (ammonium chloride), breakers (e.g. magnesium oxide), friction reducers (e.g. methanol) and corrosion inhibitors (e.g. formic acid)."

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"What is the average life time of a fracking site? How long does it take to pump all the shale gas?"
@hagitw
12/05/2015
Prof Quentin Fisher:

"Firstly, gas is not pumped from a fracked well – it flows due to the expansion of gas as pressure is reduced. Gas may continue to be produced from a well for decades. Overall, the rate of gas production falls very rapidly with time. So for example, the gas production rates after a year could be something like 10% of what they are when the well is first fracked. It is possible to refrack wells periodically to increase production rates."

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"This is one of many issues to do with the environment that people immediately take sides about, before seeing any evidence. How can we create a new kind of forum for evidence-based discussion rather than merely leave it to our politicians to decide for us?"
Julian Simcox @JulianSimcox
12/05/2015
Prof Michael Bradshaw:

"The problem is that we have a highly polarized debate with the Conservative Government and onshore oil and gas industry on the one hand saying this is too good an opportunity to miss; and environmental groups and many in local communities, on the other hand, saying that the health and environmental impacts are too great. Both sides pick and choose their information and there is hype on both sides. The Shale Gas Task Force chaired by Lord Chis Smith is trying to provide some independent evidence, but the task force is funded by industry and will not be seen as independent by the environmental groups. The Royal Society report in 2012 did suggest a large-scale academic enquiry, but this has not happened. However, there are academic groups seeking funding for research that would provide an independent evidence base. There is a public enquiry promised in Scotland and a moratorium in Wales and Northern Ireland, but while the Government in Westminster is going ‘all out for shale’ there is little prospect of a wider debate in England."

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"Why are the estimates for how much gas fracking can provide so variable? Which estimates can we trust?"
David Norton
12/05/2015
Prof Kevin Taylor:

"We use estimates from the US experience, but as UK rocks are different in age and composition we cannot reduce uncertainty on gas reserves until more exploration is undertaken. The amount of gas that can be released from a rock will depend on a number of factors that vary from one part to the next, and over a range of scales. These include the amount of pore space (holes) in the rock to hold the gas and the effectiveness with which the rock can be fractured by hydraulic fracture stimulation."

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"Would you agree that it is extremely risky to frack where the geology is heavily faulted?"
Christine Stanton
12/05/2015
Zoe Shipton

"The main risk attached to [geological] faults in shale gas is commercial. Faults often displace layers of rock vertically. A lot of the terminology around faulting comes from the days of hand carving coal faces. If you were mining along a coal seam and hit a fault, the odds are you would loose the seam. It would have been displaced higher or lower on the other side of the fault, depending on what sort of fault it was (normal faults displace the block above the fault downwards and reverse faults displace the block above the fault upwards). The same will be true in a heavily faulted shale gas reservoir – if you were drilling horizontally along your layer and hit a fault, you may well loose the productive layer of rock. You can map where the likely faults are in advance of drilling using geophysical surveys such as seismic data, but these have limited resolution and generally can't resolve features with a vertical offset lower than 10-20m. Operators will need to map any faults to evaluate the commercial risk in advance of any drilling, but are still likely to find small-scale faults that such surveys can't resolve, which could be a problem. However there are now geophysical logging tools which sit just behind a drillbit, which allow operators to "geosteer" the bit to follow the most productive layers. The other risks that have been talked about in the context of faulting are seismicity ( see question 3 ) and the risk that a fault will transmit fluids. The process of faulting affects the rock by cracking it and grinding it up as the two blocks either side of a fault move past one another. This can change the permeability of the fault rock compared to its host rock (permeability is a way of expressing how easy it is to conduct a fluid through a rock). From a review of the literature on faults cutting shales, the majority of them have reduced permeabilities compared to the host rock – this is because the process of grinding mixes the clay in the rock through the fault rock, and clay particles tend to clog up the permeability."

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"#energypanel - have we had a proper conversation with the public on fracking in our energy supply options, and if not should we?"
Alan Mercer
12/05/2015
Prof Quentin Fisher:

"The fact that significant numbers of the general public have misconceptions about fracking suggests the gas industry hasn’t been particularly good at getting their points across. There clearly needs to be continued debate about how we generate energy in the UK as new technologies are taken on board and recently adopted technologies are tested. Energy always comes at a cost and the public should have a say in how these costs are weighed up against each other."

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"How many litres of water do you use to extract one litre of gas or oil by fracking?"
Julia
12/05/2015
Prof Geoff Maitland:

"This is difficult to give a precise answer to since on average about 5 million gallons (about 20 million litres) of water are needed to fracture a typical deep shale gas reservoir per well, and this is a one off use. You then produce shale gas for many years, and it depends on the reservoir gas reserve and the duration of economic production as to eventually how much gas you produce for that water outlay. Typically 1000 Mcf, or 30,000 litres of gas are produced from a shale gas well per day. Let’s say we produce for 20 years…that is about 2 x 108 litres of gas. So that comes to about 100 millilitres of water per litre of produced gas. Clearly this is very approximate but gives a good order of magnitude for a productive site."

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"What would the panel consider to be the minimum safe distance between a fracking site and residential properties?"
Trina
12/05/2015
Prof Quentin Fisher and Prof Zoe Shipton:

ZS: "About 1 vertical km! The recent British Geological Survey estimates of resources in the Central Belt of Scotland considered a minimum depth of resource to be 805m, based on a depth cutoff of 500m plus an additional 305m to account for the likely vertical extent of hydraulic fracture heights (Monaghan, 2014 ). There are reasons of rock mechanics why you would want to stay deeper than 500m, as well as safety. The main problem with putting a frack site very close to a residential property would be noise, dust and traffic, but this is similar to any construction project. The average length of time that a frack site would be under construction for is substantially less than that of a large building going up. I believe there is a fracked shale gas well in the grounds of Dallas Ft Worth Airport."

QF: "I don’t see any significant safety concern in having a fracking site directly adjacent to a residential property. The increase in traffic and noise while the site is being drilled would mean that one would preferably drill away from residential properties. However, the increase in traffic and noise would be similar to any medium sized building project (eg building a supermarket) and that happens extremely close to residential properties."

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"Are you planning any fracking sites near London?"
Julia
12/05/2015
Prof Quentin Fisher and Prof Zoe Shipton:

QF: "I don’t think that there are currently any rock formations known to be likely to contain gas or oil directly below London. However, if they were found I wouldn’t see any safety reasons why not to hydraulically fracture close to London."

ZS: "'We' are not planning any fracking sites as we're a bunch of academics not a hydrocarbon company! The Government held the 14th round of onshore oil and gas licensing last year and the result should come out soon, which will show who has bid for which licence blocks. The whole country is divided into blocks and this webpage shows the blocks that were up for consideration in the 14th round. Some of those were in London area, but just because a block was up for consideration, does not necessarily mean anyone will have bid for them, or that if they were awarded a licence, that they would end up getting planning permission etc."

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"Labour manifesto aim: 'zero carbon electricity by 2030' - does that slam the door shut on #fracking?"
Dan Curtis
12/05/2015
Prof Quentin Fisher:

"I would have thought that for power generation one would need to link gas-fired power stations with CCS [carbon capture and storage]. However, shale gas can also be used to provide fuel for the chemical industry so either way it would not close the door on shale gas production."

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"Could you provide a "greenness" index for gas retrieved through fracking vs other fuel I would be interested in how such an index would be weighed against the cost of retrieval, factoring in the survey. For instance, if coal costs X per joule of energy it provides, and each joule gives out harmful emissions Y, Z, ... If I were to classify energy sources like that, where would fracked gas be?"
@gpap
12/05/2015
Prof Geoff Maitland:

"To answer this question one needs to do a ‘cradle-to-grave’ energy and environmental impact analysis for every energy source. Several groups are carrying out such analyses in the UK (eg DECC's energy and carbon calculator tools, Professsor Adisa Azapagic, University of Manchester or Professor Nilay Shah, Imperial College London), but they are quite complex and require good quantitative impact data. Qualitatively, shale gas takes less energy to produce than coal or oil but more than conventional gas. In terms of greenhouse gas emissions in use, shale gas is the same as conventional gas in emitting 50% less CO2 than coal or oil. The environmental impact risks during production are low if the processes are engineered, managed and monitored using well-established standards. There are short-term disruptions to local communities during the drilling and fracking of the wells, but the local footprint of the wellheads is small and comparable or less than the installation and running of wind farms and large solar panel arrays. The cost of energy production from renewable sources is still higher than for gas. Adding carbon capture and storage (CCS) to centralised facilities using gas would reduce greenhouse gas emissions to very low levels and make gas almost as ‘green’ as renewables. In the absence of CCS, my (cost x CO2 footprint) per joule ranking would be wind ~nuclear < solar ~ biomass < conventional gas < shale gas < oil < coal. You can test these things out using the DECC carbon calculator tools "

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"What are the benefits of fracking – does it have significant economic impact? And does this outweigh the risks to the environment and human health?"
Katy Stubbs @KatyLStubbs
12/05/2015
Prof Michael Bradshaw:

"In the UK, the government and industry has argued (and it remains the case based on the Conservative Party manifesto) that the development of shale gas will attract significant investment to shale gas producing regions (at present most likely the north of England), create new jobs (and preserve existing ones), improve energy security by reducing import dependence (which also benefits the UK’s balance of payments) and also promote the decarbonisation of the energy mix. The scale of these benefits is uncertain and those that oppose shale gas development certainly think that they do not outweigh the risks to the environment and human health. The government maintains that those risks are well known and can be minimized by existing regulations."

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"What are the risks of an abandoned HydroFrack site?"
@hagitw
12/05/2015
Prof Geoff Maitland:

"The risks of an abandoned (non-producing) shale gas well, created by hydrofracturing, are essentially the same as any abandoned oil and gas well. If the wellbore is not properly sealed (eg with an incomplete cement sheath binding the well casing to the rock) there is a risk that gas from the shale will build up in pressure and find its way to the surface – gas seepage. This just means that well abandonment best practice must be followed: impermeable plug seals should be placed in the well, and the well sealed with a high quality cement, resistant to degradation by any reservoir fluids that might come into the well from the shale. This is standard and well-engineered practice. The wellhead should be continually monitored for gas leaks and seepage.

Once the wellhead is closed and sealed, there is a slight risk that the gas in the shale might migrate through natural fractures connecting the shale to higher regions subsurface rock. So continued monitoring of near-surface aquifers should continue, as during production, though contamination from residues from the fracturing process will not occur as all the fracturing fluid will have been removed in the early stages of production. Similar monitoring procedures will be standard practice during well production as well."

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"In the UK what prevents companies from fracking where they want? And what are the licenses in the US? Are there any economic 'perks' for people wanting to frack?"
Hannah Rodriguez
12/05/2015
Prof Michael Bradshaw:

"First, to be able to drill you need to get a Petroleum Exploration and Drilling Licence (PEDL) and these are auctioned by the Department of Energy and Climate Change (DECC) in a so-called licencing round, the 14th round is underway with over 90 licences bid for. So, you can’t drill just anywhere you want. Once you have your PEDL you need to get various permits from the Environment Agency and the Health and Safety Executive. You also need to get planning permission to drill from the County Council and this considers a wide range of local planning issues.

As for economic perks there is agreement with government and industry on a £100,000 community payment per well site and a share of 1% of the value of production. There are also modest payments to landowners. You can find more on this at the website of the UK Onshore Operators Group and DECC’s Shale Gas site. In the US licenses are required, but there are various loopholes and regulation is a state and county issue, rather than a federal issue and there is a great deal of variation between states."

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"How can we streamline the permissions/licencing process in the UK? With only 7 shale gas wells drilled in the UK progress is painfully slow. The lack of data makes resource estimation impossible at the moment."
Tony Grindrod
12/05/2015
Prof Geoff Maitland:

"The new revised policy paper issued by the government and regulators earlier in May (‘2010-2015 government policy: energy industry and infrastructure licensing and regulation’) will hopefully help to accelerate this process, alongside the newly created Oil and Gas Authority. The paper indicates that the industry expects 20-40 new sites to be developed within the next 2 years. The Office of Unconventional Gas and Oil has been set up to encourage this process and the industry has agreed a community engagement charter, whereby it will pay £100,000 per exploration well for local community benefits and 1% of subsequent revenues. It would be good to see some explicit shale gas production targets from the government to drive an accelerated licensing process in addition to these measures."

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"Could you please explain the difference between fracking and Underground Coal Gasification (UGC)? Is one safer than the other and how do they compare environmentally?"
Dawn Ewing @DawnieDimps
12/05/2015
Prof Kevin Taylor:

"Fracking, or hydraulic fracturing, is a physical process by which fractures are created in the shale rock in order to release the gas (or oil) that is trapped in the rock. UGC is a process by which coal is partly combusted underground to produce gases (a mixture of hydrogen, carbon monoxide, carbon dioxide) which can be used to generate electricity at the surface. Both can be undertaken safely but due to being quite different processes a comparison of their surface environmental footprint is not straightforward."

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"I've seen videos online of people lighting water from their taps on fire and claiming it's due to nearby fracking wells. Can fracking make my tap water flammable?"
Ian Bushfield @ibushfield
12/05/2015
Prof Quentin Fisher:

"Fracking is very unlikely to make your tap water flammable. The video that you have seen is most likely one of the cases where a water well as been drilled through rock (e.g. coal) containing gas and the well has not been sealed properly; it was not caused by hydraulic fracturing."

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"Surely a dash for gas will bust our carbon reduction budgets? Better off keeping it in the ground."
James Clarke
12/05/2015
Prof Quentin Fisher:

"I don’t know anyone who projects that we will be carbon free anytime in the near future. I believe it’s far better to use gas instead of coal for energy production as the latter is far more dangerous to mine and CO2 emissions are higher. Replacing domestic gas use is not going to happen soon, meaning that we will need to continue producing gas. I would much sooner the gas be produced in the UK than abroad as our safety standards will be higher, it will help our balance of payments deficit [where the UK imports more goods and services than it exports] and create UK jobs."

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"Is fracking investment going in the wrong direction? In the South West @MollyMEP shows 113% energy can be met by renewables."
Lee de-Wit @leedewit
12/05/2015
Prof Michael Bradshaw:

"We do need to move away from fossil fuels and get our energy from renewable and low-carbon sources, but that is going to take quite some time. For the next couple of decades at least in the UK, natural gas has a role to play as a bridge to a low carbon future. But whether or not that demand for gas is satisfied by shale gas is a different question."

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"Fracking causes earthquakes, and getting rid of fracking waste water causes earthquakes. Isn't this a big concern for a heavily populated country like the UK?"
Judith Schmidt
12/05/2015
Prof Zoe Shipton:

"We need to define here what is meant by earthquake. Propagating fractures cause tiny events that can be picked up by sensitive microseismic instruments. These are usually placed down a borehole to avoid the background noise that comes from traffic etc, and can be monitored to see how the fractures evolve with time and between jobs. From US data, these are usually magnitude 1 to 2 and will be undetectable by people at the earth's surface (earthquake magnitude is measured on a logarithmic scale, remember, so a magnitude 2 is 10 times stronger that a 1, a magnitude 3 is 10 times stronger than a 2, and so on). Very few frack jobs have caused events large enough to be felt by people at the surface.

The two events in Lancashire in 2011 were the first recorded example of what is called "felt seismicity" linked directly to a frack job (magnitude 1.7 and 2.3). They were probably caused by fluid from a fracture entering a fault that was already close to failing. The events were below those commonly felt in old coal mining areas of the UK (up to magnitude 4). Whether an earthquake is felt by the public or not depends where you are – a magnitude 2 to 2.5 is unlikely to be felt in an urban area where background vibrations from traffic are of similar magnitude.

Wastewater from conventional hydrocarbons and shale gas in the US has been disposed of by pumping underground. This would not be permitted by regulators in the UK. Wastewater disposal impacts a larger volume of rock and for a longer period of time than in a fracked shale gas well. In the US this has caused events up to magnitude 5. An event of this size is unlikely to cause any damage to buildings. See here

Seismic events could potentially damage the integrity of a well if the event caused shearing of the well casing – indeed, this did occur in Lancashire. This is not uncommon in the industry and an operator could run down-hole tools to assess the extent of any damage. In the event that any damage compromised the well beyond repair, that section of the well could be plugged and abandoned."

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"Regarding the ASA ruling on the Greenpeace advert is there a scientific consensus that fracking will not lower prices?"
Jane Turner
12/05/2015
Prof Michael Bradshaw:

"This is a complicated one. The complaint was made because the Greenpeace advert suggested that there was consensus that shale gas development (in the UK) would not bring down gas prices. As the complainant, Labour Peer Lord Lipsey, maintained, there is a range of views on the subject. The UK has an open gas market with supplies from our own continental shelf (which are falling), the Norwegian continental shelf, supplies from elsewhere in Europe via the interconnectors and also supplies from the global LNG market. The UK gas price is determined by gas-to-gas competition and the laws of supply and demand and is known as the National Balancing Point (or NBP for short). As we don’t know what the future scale of domestic gas production might be, what future demand might be, or what future conditions might be in the wider European gas market or the global LNG market, we cannot say with any certainty what impact shale gas production might have on future gas prices in the UK."

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"So how does fracking actually work? You pump water down a hole and the gas flows back up with the water?"
Kelly Green
12/05/2015
Prof Geoff Maitland:

"Water containing sand or other fine solids, sometimes with additives to thicken the water and keep the sand in suspension, is pumped into a well at pressures that fracture layers of shale rock. The layers are selectively exposed to the pressurised fluid through perforations in the steel casing that lines the well. The fractures propagate into the shale formation and the fluid flows into them, continuing to pressurize the rock and creating a network of fractures until the pressure energy is dissipated, filling the fractures with the sand, or ‘proppant’ as it is called. The pressure in the well is then reduced so that it is now lower than in the reservoir; two things happen. The fractures would close up unless they are kept open by the sand proppant – so they remain open and provide a high flowrate pathway for the gas within the shale to flow out, rather than being trapped in the very low permeability unfractured shale rock. The pressure gradient (lower in the well than the reservoir) then causes the water (with some gas) to flow back out of the fractures into the well and back to the surface where it is collected (and treated and sometimes re-used). The low pressure in the well then sucks the shale gas into the fractures, which then flows along these out through the perforations into the well, and then flows up to the surface, often several kilometers up, to be collected at the wellhead."

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Colin Axon
"If energy independence and security is such an issue now, why wasn't that considered a priority when we were a net exporter not so long ago?"
Lisa C
27/04/2015
Colin Axon

"Energy independence does not necessarily mean security. For oil and electricity in particular, trading is very important. Oil has different grades and qualities around the world and each is suited to various products. Electricity from renewables is generated and used at various times across Europe, so trading enables networks in different counties to more easily balance supply with demand. Most natural gas produced in the UK is used within the UK. Why Governments choose to prioritise different issues is not something the energy research community can answer."

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Adrian Bull
"Costs of Germany shutting down its nuclear program seem really high compared to new build in the UK! Does it cost more to dispose of nuclear fuel that isn't completely used?"
Carl Keal
21/04/2015
Adrian Bull:

Comparing new build construction costs for new UK reactors with the decommissioning and clean-up costs for the German nuclear fleet is not comparing like-for-like. The German figure reflects the costs of dismantling and disposing of all reactors as well as dealing with used fuel and radioactive waste. New build costs just cover the price of building new reactors. As the UK’s new power stations operate over several decades, a levy from each unit of electricity sold will be set aside towards the eventual decommissioning and clean-up costs, so these costs will be covered when the time comes for these reactors to be shut down.

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Dr Niall Mac Dowell
"The Labour manifesto says it will create an ‘Energy Security Board to plan and deliver the energy mix we need, including renewables, nuclear, green gas, carbon capture and storage, and clean coal.’ But what are green gas and clean coal and are they different to carbon capture and storage?”
James Boyle
21/04/2015
Dr Niall Mac Dowell:

“Green gas” refers to “bio gas” which is methane produced from the breakdown of organic matter. The term “clean coal” is often used to describe more efficient power plants that emit less CO2 (per MWh). It also describes coal plants that have other pollution controls such as flue gas desulphurisation for the removal of sulphur dioxide, or selective catalytic reduction which eliminates nitrogen oxides, from the gas that leaves power plant chimneys. Carbon capture and storage (CCS) is the act of capturing CO2 and then compressing and transporting it for secure and long term storage underground.”

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Prof Zoe Shipton
"Are the increased number of earthquakes in Oklahoma definitely down to fracking? Are these earthquakes of a severity that could threaten our homes? (In relation to this article in the Independent)"
09/04/2015
Prof Zoe Shipton:

The earthquakes in Oklahoma are most likely due to the disposal of wastewater, not due to the fracking process itself. The Lancashire events in 2011 remain one of the very few instances of fracking-induced seismicity. A magnitude 4 on the Richter scale is likely to cause alarm, but not damage any buildings unless there was plaster close to falling off or loose chimney pots. See here.

Disposal of wastewater by re-injection is not permitted by the Environment Agency. If any fracking took place in the UK, the wastewater would have to be treated in a water treatment plant.

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Laurence Stamford
“What is the environmental impact of the production of solar panels, does the amount of energy produced outweigh the environmental production costs, and can the panels be disposed of in an environmentally friendly manner given their 25 year shelf life?”
Saadat
27/03/2015
Dr Laurence Stamford:

In terms of climate change, solar panels are definitely beneficial even including their manufacture. Over their entire life cycle they generate around 80g of CO2-equivalent per kWh generated (for a panel in the UK), while our current electricity mix generates approximately 500g. However, there is an impact of producing, transporting and installing panels which must be considered, which means that the solar power life cycle consumes far more resources (like metal ores) than other energy technologies. It's also not very competitive in terms of toxicity impacts. So you're basically trading off different costs and benefits.

Also bear in mind that the UK is not a very sunny country: solar panels in Spain can produce twice as much electricity, which essentially halves their environmental impact.

As for end-of-life, panels will last longer than 25 years but their efficiency decreases as they age. Generally speaking they can - and certainly should - be recycled, but that's not an area we have much experience of yet because not many have reached the end of their lives.

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Colin Axon
"Costa Rica has been using only renewable energy to generate its power for 75 days running. Can the UK achieve this too? When?"
26/03/2015
Colin Axon:

Costa Rica is a small developing nation with about four million inhabitants. The GDP per capita is about a quarter that of the UK. Energy use is strongly related to GDP. Costa Rica is a mountainous country which has allowed the construction of many large dams for hydro generation. This supplies nearly all of their power needs for industry, shops, offices, and homes. However, Costa Rica remains entirely reliant on imported oil for transport. As for the UK – the target is for an 80% reduction. So even by 2050 the UK would still be using fossil fuels, almost certainly for both buildings and transport. With current lifestyles and industrial use it will be very difficult for the UK to get to 100% renewable in the medium term.

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Dr Cecilia Fenech
There's a new toilet that can use energy from urine to power a light source. But if we can get energy from human waste, why aren't we already doing it at sewage farms?
13/03/2015
Dr Cecilia Fenech: In fact, we are already producing energy from human wastes, through Anaerobic Digestion (AD) plants in connection with sewage treatment plants. We have around 150 AD plants in the UK associated with the water industry, which produce biogas.
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Dr Laurence Stamford
How much CO2 will fracking dump into the atmosphere vs leaving it in the ground & focussing on renewables?
Steve Owens (@darkskyman)
09/03/2015
Dr Laurence Stamford:

Good question. One of the most difficult issues with new fossil resources is whether we can really afford to extract them. According to the British Geological Society, there are about 38 trillion m3 of shale gas in central Britain. If we could extract 10% of that and burn it for electricity, we'd produce about 8.1 billion tonnes of CO2-equivalent (based on the entire life cycle). That's 12% more than the UK’s entire legislated carbon budget for the period 2013 to 2027. In other words, there would be no emissions budget left for transport and heating from any other fossil fuel sources. So, basically, it's likely that carbon capture and storage would be essential.

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Chris Goodall
"I heard that energy companies are worried about next month's solar eclipse disrupting electricity supply from solar panels. I have panels on my roof, will it affect my hot water supply? And how likely is it that Europe's electricity supply will be interrupted by the eclipse?"
Asha Buch
02/03/2015
Chris Goodall

During the eclipse there will be some impact on the electricity output of electricity-generating or 'photovoltaic' (PV) panels. But the eclipse will last less than two and a half hours and the effect on total electricity generation will be small. Grid operators around Europe have been preparing for the effect for some time. The eclipse will be relatively early in the morning, peaking at around 9.40 GMT and, of course, if the day is cloudy the effect will be minimal. The German grid is most likely to suffer, facing a reduction in its national PV output of almost 400 MW every minute for half an hour as the sun is covered.

The UK is relaxed. Here’s what National Grid thinks: ‘The change in residual demand caused by human behaviour (halting normal activities to observe the eclipse) will dominate the PV effect. The PV effect acts in the opposite direction on the residual demand to the human-demand effect, and so will in fact ameliorate the situation.’ In other words, the fall in PV output will actually help stabilise electricity supply.

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Prof AbuBakr Bahaj, University of Southampton
"Are we really in danger of "the lights going out" if we don't start fracking?"
Steve White
03/02/2015
Prof AbuBakr Bahaj:

This statement is not true at all. Fracking, if approved, will take a long time to develop and to become part of the mainstream gas supply to the power sector. There is no certainty in the amount of gas the UK have or can extract. There are other solutions for the UK that can be enhanced or developed – renewables, imported gas (including increasing our storage facilities), EU grid connectivity, nuclear, clean coal, etc. Also there are other electrical power capacities within the UK that can be brought into the mainstream power generation to plug any holes in supply. Furthermore, the reduction in the cost of oil and gas in the international market is also indicative that other options will be found before we can even contemplate “the lights going out”.

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Dr Laurence Stamford
"What is the climate impact of fracking compared with other forms of fuel? This should take into account the whole process, rather than simply the fact that burning methane is better than burning coal. (So includes known/estimated fugitive emissions of methane, impact of HGV journeys for water/waste water for fracking etc.)"
Steve White
02/02/2015
Dr Laurence Stamford: There’s a lot of work in this area at the moment, mainly because there can be huge variation in fugitive emissions and industry practice. There have been several life cycle assessments of fracking in the last four years – in fact I published one last year with Adisa Azapagic. The general consensus is that the life cycle GHG emissions of shale gas are quite similar to conventional gas: probably worse than North Sea gas but better than imported LNG (liquefied natural gas). Our best estimate, which agrees quite well with other studies, showed that using shale gas for electricity generation creates about 460 g CO2-equivalent per kWh. For reference, coal power is about 900-1100 g/kWh and wind is about 10 g/kWh. But as I said, there can be a lot of variation and in the worst case fracking could be similar to coal (although it’s unlikely).
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Prof Peter Hall
"What are the prospects for storage [of electricity from renewable sources] in the future? Surely this will massively increase the efficiency of current windfarms."
08/01/2015
Prof Peter Hall:

Quite simply, when there is a surplus of energy on electrical grids, it is much faster and easier to disconnect wind energy from and continue using fossil fuel sources. With increasing penetration of renewables, this is happening with increasing frequency. One option would be for wind to producers to store this energy and sell it back to the market when electrical spot prices are at a maximum, typically early evening.

There are many technologies for storing energy, the most common being to pump water up hill ad release it at the appropriate time through a turbine. Other technologies that are being developed and considered are the use of lithium titanate batteries, cryo-energy storage, redox flow batteries, compressing air and producing a combustible gas such as hydrogen. All of these technologies have their advantages and disadvantages but it certain that a combination of them will be in routine use from 2020 onwards.

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Chris Goodall
"Can we harness the power of hot springs to heat homes?" "Yes Romans did it in Bath thousands of years ago."
@claudemmx2
22/12/2014
Chris Goodall:

There’s a surprising number of places around the world that use the heat from very hot rocks. In Italy and Kenya, for example (although in both places the very hot water turns to steam and is used to drive electricity turbines). Kenya is targeting a figure of about 25% of its total electricity need eventually from ‘geothermal’ heat. There’s the possibility of using geothermal energy in Cornwall and at the Newberry extinct volcano in Oregon, USA.

And you might be surprised to know that a small number of buildings have been heated by hot (but not boiling) water in central Southampton for some years.

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John Roberts
"Here in #Yorkshire the declining mining industry is a raw issue. Which energy could utilise skilled labour most? #Energypanel"
@WRPsocial
22/12/2014
Dr John Roberts:

Any industry would welcome skilled labour. I know most about the nuclear industry and that is expanding as well has having an above average number of people retiring, so skilled people are definitely required. There are no nuclear power plants in Yorkshire but there are many companies involved in the supply chain and universities in Yorkshire involved in nuclear education and research.

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Dr Laurence Stamford
"When comparing different energy technologies' carbon footprints, what time scales are considered? How many years for nuclear, wind turbines, fracking etc?"
George Field
22/12/2014
Dr Laurence Stamford:

When you calculate a carbon footprint you should consider the entire life cycle, from extracting ores and fuels to transportation, construction, installation, decommissioning and waste disposal. So the time considered depends on the technology itself. For a wind turbine, all of that will happen in roughly 30 years, whereas with a nuclear plant it’ll be an absolute minimum of about 60 years.

However, there’s also the question of how we consider the behaviour of greenhouse gases in the atmosphere. Different gases have differing lifetimes. For example, methane doesn’t remain in the atmosphere for as long as CO2. Normally we use a timeframe of 100 years for the calculation, so all greenhouse gases are normalised to the impact of CO2 over a 100 year time period. Some people think we should use 20 years instead, in which case the relative impact of methane becomes much worse, therefore the carbon footprint of any technology involving gas leakage also becomes worse.

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Adrian Bull
"What's the difference between electricity and energy?"
Chris Peters
22/12/2014
Adrian Bull:

Electricity is the power which comes out of the socket in the wall – used for electrical items like TVs, fridges, kettles, washing machines, computers, charging phones etc. as well as lighting and sometimes heating. Energy is much broader – including all the transportation fuels such as petrol, diesel and airline fuels, plus the burning of coal, oil and gas for heating.

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Dr Laurence Stamford
"I often hear elected representatives supporting mixed energy policies. Focusing on emissions, can 'mix' be best?"
Scott Nicholson (@scott993)
22/12/2014
Dr Laurence Stamford:

I assume we’re referring to politicians supporting a mix of energy technologies rather focusing on one particular option. A mix of technologies will be essential for several reasons. Firstly, from a technical perspective things like wind and solar are variable in output while nuclear is difficult to ramp up and down on a minute-to-minute basis, therefore we need other things in the mix to match supply and demand. We could use vast amounts of storage but it would have similarly vast implications in terms of costs and emissions. Secondly, there are energy security issues associated with relying on one technology. Thirdly, it’s worth bearing in mind that certain things such as heat (which we use more of than electricity) normally involve burning things, therefore if we had, for instance, an entirely wind-powered energy supply, we’d need to completely electrify all of our heating supply and build about three times as many turbines (roughly 80,000 large turbines in this case) to compensate. If you have a mix of, say, biomass, gas, nuclear, wind, solar, etc. then it all becomes much more practical. Finally, if you look at the full life cycle of different technologies, they each have positive and negative impacts, so it’s normally a good idea to avoid putting all your eggs in one basket. Sorry for the long answer: it’s difficult to summarise!

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Dr Cecilia Fenech
"What's the bit of tech you're most excited about regarding energy/climate?"
Celia Makin
22/12/2014

Dr Cecilia Fenech:
"In terms of energy and climate change, I am excited about the increasing efforts for obtaining ‘energy from waste’. This is not a specific piece of technology, but a number of technologies working together to provide a renewable source of energy. Thus, rather than contributing to increased greenhouse gas emissions by disposal in a landfill, these wastes could become a resource and provide energy. Technologies that optimise energy production from such wastes is particularly interesting."

Dr John Roberts:
"It’s got to be ITER - the prototype fusion reactor being built at Cadarache in the south of France. If this performs as forecast it will be a real game-changer. Enormous quantities of fuel, with incredibly small carbon emissions."

Dr Laurence Stamford:
"That’s a tricky one; there are a few options… It may sound boring, but a big leap in battery technology (think graphene/nanotube electrodes etc.) could completely change the energy and transport sectors and solve a lot of problems. In terms of generation, there are lots of really interesting Generation IV nuclear designs that could generate their own fuel and incorporate passive safety (automatic shut down in an emergency). Unfortunately the UK’s funding for nuclear R&D is nowhere near what it used to be, so we’ll have to wait for countries like Russia and China to develop most of it for us."

Chris Goodall:
"I’m going to cheat and give you two. First, the new solar panel coatings developed by Prof. Henry Snaith at Oxford and commercialised at Oxford PV. If you want to know more, search for ‘Perovskite solar cells’. Second, the very cheap vertical wind turbines invented by Dr Giles Rodway at Spinetic in Swindon. The key thing here is that these ‘wind fences’ can be installed everywhere with reasonable wind and because they are so inexpensive they generate electricity at an effective cost of less than a gas-fired power station.

"More generally, things are moving really fast. I’m more optimistic than I’ve been for decades…."

Dr Niall Mac Dowell:
"I'm more conceptual, so a single "bit of tech" doesn't get me that excited. In terms of ideas, however, I think that CCS and large scale (or grid scale) energy storage - such as power to gas technologies - are really exciting. They are two key enabling technologies to allow us to safely transition to a sustainable energy system."

Adrian Bull:
"Wow - what a question! In nuclear, there is exciting work going on now to look at Small Modular Reactors, and the potential for those to play a big part in meeting the UK's future electricity needs. There is also a big opportunity for UK firms to contribute to the supply chain for those systems.

"More generally, if scientists could develop a really efficient and cost-effective way to store energy, then it could revolutionise the role which renewable energy could play as part of the overall low-carbon energy mix."

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Chris Goodall
"Energy flooring - is this ever going to be cheap enough to make a difference? What about in the parts of the world where there isn't any energy at all?"
James Clarke
22/12/2014
Chris Goodall:

Do you mean flooring that uses the kinetic energy of people walking and converts it into electricity? If so, I’m afraid it doesn’t help very much. No more than about 1 kilowatt hour a day is expended by the average person in movement. But in advanced countries we typically use about 100 times that amount. Even if we could capture a significant portion of human kinetic energy we’d only get a small fraction of 1% of the energy we need.

Your second question is about places where there is no accessible energy. No sun, no wind, no tides or waves. No plant growth for use as biomass energy. These places are pretty unusual and – for obvious reasons – few people live there. These areas can be supplied with liquid fuels made from biological materials or renewable energy, perhaps hydrogen, shipped in. Not easy but better than nothing!

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Niall Mac Dowell (@Niallmacdowell)

"If you showed pollution per capita, your graph would be meaningful. As it stands, I can tell China is a big country. What's the best way to represent data on pollution - per capita? Total national emissions? Both?"


CO2 emissions chart | The Guardian

Andrew Richards (@andrewwr235)
22/12/2014
Dr Niall Mac Dowell:

Both metrics have merit. For example, if you look at CO2 emissions per capita, Qatar (small on population terms) is one of the largest – if not the largest – emitters in the world – a consequence of the particular industrial circumstance of that country.

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Dr Laurence Stamford
"The energy with the lowest emissions is energy use avoided. What are the scientific prospects for radical reductions in usage and dramatic increases in efficiency?"
Mike Tuffrey (@Mike Tuffrey)
22/12/2014
Dr Laurence Stamford:

I agree entirely that demand reduction should be a priority. There's significant potential for savings here: e.g. almost a quarter of UK electricity demand is for lighting. That's roughly 90 billion kWh per year on lights. Switching to LEDs etc. would remove the need for several large power stations. In heating there are even more savings. Heat demand is roughly 700 billion kWh per year, almost all from gas, and our housing stock is very old and badly insulated. So we could reduce that enormously. In transport, electric cars are around 90% efficient compared to ~25% for internal combustion engines, so providing we source electricity from reasonable technologies there's huge potential savings there too.

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John Roberts
"Nuclear submarines generate their own electricity - could large buildings in our cities do the same?"
Alex Cutler
22/12/2014
Dr John Roberts:

There is nothing technically that would stop this occurring. The main problem would be the public perception of nuclear power plants (NPPs). Submarines and NPPs operate mainly in remote locations which have less public opposition. NPPs have lots of people working there 24 hours a day so fundamentally there is nothing to stop people living in the same building as a nuclear reactor.

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John Roberts
"Is it really inefficient to transfer electricity over large distances? Should we have more smaller power plants?"
Rosie Jenkins
22/12/2014
Dr John Roberts:

We can overcome losses by using high voltages but this requires transformers to get the required 240 V for household use or higher for industrial use. Smaller power plants would overcome this but people generally want the electricity production sites in remote places. Having, for example, a coal-fired power station on every street would be impractical, countless deliveries of fuel, possible impact on the air quality, etc.

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Chris Goodall
"Can the electricity grid in the UK be linked to the rest of Europe so we can use their electricity when we need it and they don't?"
Rosie Jenkins
22/12/2014
Chris Goodall:

Yes, it can be much better linked, and should be. The National Grid wants to double capacity by 2020. We can import/export about 4 GW at the moment (about 7% of peak demand) and this certainly needs to rise sharply. We particularly need more interconnection with northern Europe, including Norway. In the long run, we need to be looking at linking to Iceland, which has the possibility of providing us with substantial amounts of electricity from its natural sources.

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Chris Goodall
"I know that renewables can generate clean electricity - but what about energy to heat our homes - can renewables do that too?"
Tom Bell
22/12/2014
Chris Goodall:

"Most people think that heat pumps (reverse fridges) can provide much of the heat needed for winter. Heat pumps need electricity, of course, but this can be renewable. Or we could use hydrogen fuel cells or natural gas made from renewable sources such as anaerobic digestion".

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Adrian Bull
"I hear lots about how nuclear power in the future will be able to use our old nuclear waste - if that's the case then why is the Government looking to spend billions on long term storage of this waste?"
Lee Walker
22/12/2014
Adrian Bull:

Some future designs of reactors are potentially able to use SOME of what we currently consider to be “waste” as a source of new fuel. There will be a substantial cost involved in converting the waste into a suitable form, though – so we need to find out if that can be more cost-effective than making new fuel from scratch. Also there will still be a lot of highly radioactive waste which can’t be re-used in this way – so an ultimate disposal route will still need to be found. That will be an underground repository, and much of the cost will be fixed cost, meaning it doesn’t depend on the capacity of the repository itself. So any cost saving from re-use of some of the waste may not save as much money as you might hope.

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Dr Cecilia Fenech
"One for all the panelists - to reach our 2050 target [80% GHG reduction] we need to move away from fossil fuels - but which single energy source is most likely to replace it?"
Steve Parkinson
22/12/2014

Dr Niall Mac Dowell:
"It is unlikely that we will move away from fossil fuels in the near term; in reality they will likely continue to provide the majority of our energy until the end of the century, if not beyond. This is one of the reasons that CCS will become an increasingly important technology as the century progresses. After that, our energy portfolio will likely become increasingly diverse, with renewable energy playing an important role, which therefore motivates the development of energy storage technologies."

Dr Cecilia Fenech:
"I do not think that a single energy source is likely to replace fossil fuels. Rather, a mixed energy source scenario is likely to be the future of energy supply. In order to ensure sustainability of the industry as well as security in our energy supplies, a mixed energy source scenario is likely."

Dr Laurence Stamford:
"Unfortunately there isn’t a single energy source that can. Fossil fuels are uniquely useful in terms of energy density and breadth of application, which is quite frustrating! People often talk about ‘silver bullet’ technologies like fusion, but they’re much too far away to be useful in this case. Electricity is relatively easy to decarbonise with a mix of renewables and nuclear, but transport and heat are much harder, so we’ll need to reduce demand and electrify as much as possible. Looking very long-term it’s reasonable to assume that solar technologies might more or less replace fossil fuels, but it’ll take much longer than the 36 years left before 2050."

Prof AbuBakr Bahaj:
"No single source will be able to achieve our needed energy supply – heat, electricity and transport. So it will have to be a mixture of sources. It will be possible to have zero fossil fuels, but one needs to understand the implication of this (Germany are currently trying this out). For us we need to have huge storage capacities (electrical and thermal), use air source heat pumps and make our homes, offices and transport very much more efficient, etc. Our grid infrastructures may have to change also. These have cost implications, and affordability as a nation has to be part of the debate."

Dr John Roberts:
"The easiest way to achieve this target is by using Generation III/III+ nuclear fission. If the answer is not to be nuclear fission we will need to increase dramatically our investment into storage research to enable this to become a viable alternative."

Chris Goodall:
"It could be solar power or it could be nuclear, with a lot of wind added in for assistance. Solar looks as though it is going to be much cheaper than nuclear. But we will need a lot of energy storage as well to make it work."

Adrian Bull:
"If I had to pick one energy source, I’d go for nuclear – the only proven, large-scale provider of low-carbon, reliable round-the-clock power. But the reality is that the best solution will be a mixture of sources – nuclear, renewables and burning fossil fuels with “carbon capture & storage” technology to prevent the greenhouse gases going into the atmosphere."

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Live online Q&A
"Tidal stream - is that like under water wind turbines? How long do they last for in salt water?"
Helen Reegan
22/12/2014
Prof AbuBakr Bahaj:

Tidal stream uses technologies similar to wind turbines, with some subtle differences. It uses the flow in the water to generate power in the same fashion as wind turbines use air. The current designs for tidal stream turbine is to last for 20 – 25 year with periodic maintenance.

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Live online Q&A
"A new tidal lagoon is being proposed in Swansea bay - isn't this going to be hugely damaging to the local environment?"
Carolyne Hunter
22/12/2014
Prof AbuBakr Bahaj:

There are always risks in any interventions within the our environment. However, these risks will need to be identified and addressed before any licence is given. Going through this process will give an indication of any damage or otherwise. It looks like the developers have gone through this process and weighed up the perceived risks. No licence will be granted if damage to the local environment is identified.

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Niall Mac Dowell (@Niallmacdowell)
"Energy generation by sustainable, low emission methods needs to get much, much cheaper before it is a properly viable option. It could even be argued that our economy is paying the price for leaping too soon and the so-called growth in the system is being paid for by personal debt. Would it not be more sensible to use, for instance, fracking to produce much cheaper energy in the short term and then plough much of the savings into massive research into sustainable power that is both efficient, storable and low cost? It might then even be able to take on the whole burden of supply rather than just part."
Joss Sanglier
22/12/2014
Dr Niall Mac Dowell:

All of these discussions start from a position of agreeing that anthropogenic climate change is both real and a very serious challenge for this century. Firstly, any form of low carbon energy will be more costly than that same amount of energy generated in a less sustainable way. On this basis, Carbon Capture and Storage (CCS) is comparable with other forms of low carbon energy. Thus, it will always be possible for one to stand by and say that a technology transition will cost too much. Delaying action to address climate change will force us farther down the adaptation path. It is well described by the Intergovernmental Panel on Climate Change (IPCC) that adaptation will be significantly more costly than mitigation. Arguably, there is currently massive research ongoing, both in the UK and globally, into sustainable energy and energy storage. However, it is clear that we need to act soon to address climate change, and CCS is one technology option which is sufficiently well advanced for immediate deployment.

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Prof AbuBakr Bahaj
"How much energy - in terms of homes powered - can tidal energy supply in the short term?"
Chris Peters
22/12/2014
Prof AbuBakr Bahaj:

Let's assume the average UK domestic electrical demand per household is 4000 kWh/year. There are two types of tidal energy: 1) Tidal current or tidal stream, which is projected by some to produce around 20 TWh/year for the UK. So according to the above, this will supply around 5.0 million households. 2) Tidal range (Outer Severn barrage proposal): is projected to produce around 36 TWh/year. So this means it can supply 9.0 million households. The two types of tidal power will supply around 14.0 million households with electricity (not all of our energy) out of a total of 26.4 million UK households.

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Dr Cecilia Fenech
"What is anaerobic digestion? And how much of the UK's energy comes from it? Can we get it more easily?"
Georgie Smythe
22/12/2014
Dr Cecilia Fenech:

Anaerobic digestion (AD) is a process that utilises natural micro-organisms to produce biogas (used to produce energy as heat and/or electricity) and digestate (a fertiliser) from waste biodegradable materials. This works similar to a cow gut, but the methane that is generated is collected and used for energy purposes, whilst the remaining solid material (called digestate) can be used as a fertiliser. As of October 2014, there were 310 AD plants in the UK. Of these 152 are sewage plants, whilst the remainder (157) are non-water industry plants.

In 2013, it was estimated that 1.5 terawatt-hours (TWh) were produced from all the AD plants in the UK. This is equivalent to providing energy to 400,000 homes. However, it estimated that anaerobic digestion can contribute up to 40TWh within the UK.

Increasing the energy share of Anaerobic Digestion is expected to occur by increasing the number of AD plants outside the water sector. This sector has seen significant growth in recent years, with the number of plants doubling every three years or so in the last decade. Through the course of 2014 at least 30 new plants have been commissioned.

Further information can be found here.

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Niall Mac Dowell (@Niallmacdowell)
"All of the DECC emissions projections have the UK capturing CO2 from fossil fuel power plants in the not so distant future. But isn't this pretty optimistic? I didn't know there were any large scale CCS plants anywhere in the world!"
Daniel Curtis
22/12/2014
Dr Niall Mac Dowell:

Actually, there are several CCS projects ongoing in the world, with different elements of the CCS chain proven at scale for several decades. Earlier this year, the first commercial scale CCS project in the world opened in Canada at the Boundary Dam Project. In the UK, we're working on two projects: White Rose and Peterhead. Check out the Global Carbon Capture and Storage Institute website for more details of this.

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Niall Mac Dowell (@Niallmacdowell)
"What is CCS and if we're trying to reduce our burning of fossil fuels - why does it matter?"
Anne Reegan
22/12/2014
Dr Niall Mac Dowell:

CCS stands for Carbon Capture and Storage – it provides an efficient and affordable way to use fossil fuels and subsequently geologically sequester the associated carbon. Actually, we're trying to reduce our carbon emissions – CCS provides a way for us to continue exploiting fossil fuels, but in an environmentally benign and sustainable way.

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Chris Goodall
"Spray on solar panels? Likely to help or likely to be a load of hype?" (http://dailym.ai/1qVJ2DC)

Jane Rodriquez
22/12/2014
Chris Goodall:

"Photovoltaic technology is advancing at an astounding rate. We’ve known we can make electricity from dyes on glass for some time. My bet is on a related technology – perovskites – which can be sprayed on to conventional solar panels to boost their performance."

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"How will fracking affect the UK's energy security?"
@BilboGeogAmb
30/11/-0001
Prof Michael Bradshaw:

"The UK Government sees energy security as related to two issues: the physical security of supply – can we guarantee access to the gas supplies that we need, and price security – can we access that gas at prices that are affordable to our economy and population. When it comes to physical security, the level of import dependence and the diversity of supply are paramount. At present we import about a half of the gas that we consume. Those imports come by pipeline from Norway and from the continental gas market and also as LNG to three terminals.

As our production declines in the North Sea and in the absence of significant shale gas production onshore, we could be importing 70% of our gas needs. But the diversity of supply source should ensure physical security of supply. How much we will have to pay for that gas is uncertain. Finally, if we reduced our gas demand through energy efficiency and alternative sources of energy, that would reduce the volume that we need to import, and that would improve the UK’s energy security."

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