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'The Ugly Truth'

by Tracey Brown, director of Sense About Science

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Can we get the energy we need without the emissions we don’t want?

Image by Michael Coghlan(CC BY-NC 2.0)

Every aspect of modern life, be it education, healthcare, agriculture or manufacturing, requires energy. But in the UK and the rest of the world, generating the energy we need causes emissions we don’t want. What are the technologies and innovations that could give us more cheap energy while reducing the amount of greenhouse gases produced?

How much of the world could get its energy needs reliably from solar panels? Will the next generation of nuclear power plants mean we can use up all the nuclear waste in Sellafield? And it’s hard to know whether carbon capture will mean fossil fuels will be less of a problem or if we’ll be able to effectively store energy to use when we need it most.

On Monday 22nd December 2015 our expert panel (Dr Cecilia Fenech, Dr John Roberts, Adrian Bull, Prof AbuBakr Bahaj, Chris Goodall, Dr Niall Mac Dowell and Dr Laurence Stamford) answered your questions.

If you have a question on an energy related issue then get in contact with our energy panel via Twitter, @senseaboutsci using #energypanel, or email us at [email protected].

1."Spray on solar panels? Likely to help or likely to be a load of hype?" ( (Andrew Richards)

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."

2."What is CCS and if we're trying to reduce our burning of fossil fuels - why does it matter?" (Anne Reegan)

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."

3. "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)

NMD: "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".

4. "What is anaerobic digestion? And how much of the UK's energy comes from it? Can we get it more easily?" (Georgie Smythe) 

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 at: or through the AD & Bioresources Association ("

5. "How much energy - in terms of homes powered - can tidal energy supply in the short term?" (Chris Peters)

Prof AbuBakr Bahaj (ASB): "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."

6. "A new tidal lagoon is being proposed in Swansea bay - isn't this going to be hugely damaging to the local environment?" (Carolyne Hunter)

ASB: "There are always risks in any interventions within 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."

7. "Tidal stream - is that like under water wind turbines? How long do they last for in salt water?" (Helen Reegan)

ASB: "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 years with periodic maintenance." 

8. "I know that renewables can generate clean electricity - but what about energy to heat our homes - can renewables do that too?" (Tom Bell)

CG: "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."

9. "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)

Adrian Bull (AB): "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."

10. "Nuclear submarines generate their own electricity - could large buildings in our cities do the same?" (Alex Cutler)

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."

11. "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)

CG: "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."

12. "Is it really inefficient to transfer electricity over large distances? Should we have more smaller power plants?" (Rosie Jenkins)

JR: "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 a, for example, coal fired power station on every street would be impractical, countless deliveries of fuel, possible impact on the air quality etc."

13. "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)

NMD: "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."

14. "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)

NMD: "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."

CF: "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."

ASB: "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."

JR: "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."

CG: "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."

AB: "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."

15. "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?" (@MikeTuffrey

LS: "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."

16. "What's the bit of tech you're most excited about regarding energy/climate?" (Celia Makin)

CF: "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."

JR: "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."

LS: "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."

CG: "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…."

NMD:  "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."

AB: "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."

17. "What kind of energy tech R&D is going on? Is it public sector, or mostly private sector funded?" (Sile Lane)

LS: "Perhaps I’m biased because I work in a university rather than the private sector, but I’d estimate that much more is publicly-funded than private. However, it depends on what’s known as the TRL or Technology Readiness Level, which describes how far away something is from being commercially viable. Public money tends to fund the stuff that’s currently nowhere near profitable but will be in the future, whereas private companies work on things that are ‘nearly there’ (i.e. technologies that can make them money very quickly). Most funding on the projects I’m aware of comes from the UK Engineering and Physical Sciences Research Council (funded by the public) and/or the EU (also public).

As for types of R&D, to name a few areas, there’s a lot going on in energy demand reduction, smart grids, solar PV and alternative nuclear fuel cycles (although most of that is outside the UK)." 

AB: "In the nuclear industry there is a lot of international R&D collaboration going on funded by governments, given the high costs and long timescales of such programmes. The UK has been absent from much of this work until recently, and we're now looking at how best to re-engage with those programmes.

In the UK, most nuclear R&D is short-term and funded by the private sector, however Government has set up a body to look into what longer-term nuclear research should be done, which would be funded by Government. Those recommendations are likely to be published in the spring of 2015."

18. "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)

CG: "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!"

19. "What's the difference between electricity and energy?" (Chris Peters)

AB: "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."

20. "Can we put solar panels on the moon? What happens when cables get tangled around the Earth?" (@claudemmx2)

CG: "Yes, we could put solar panels on the moon. I don’t know, but I suspect that Apollo moon landers had rudimentary panels on them. And because there’s no atmosphere and the moon doesn’t spin, in a sunny place we’d get more power from each panel. However returning the electricity to earth would be a problem. It’s conceivable we could do it using microwaves (although I’m a bit out of my depth here) but I suspect it wouldn’t really be worth it. We get about 10,000 as much solar radiation on the earth as we need for all the planet’s current requirements. More panels are needed in deserts, on roofs and in other places where they don’t disrupt agriculture much (as in most of the UK)."

21. "I often hear elected representatives supporting mixed energy policies. Focusing on emissions, can 'mix' be best?" (@scott993)

LS: "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!"

22. "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?" (@andrewwr235)

NMD: "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." 

23. "When comparing different energy technologies' carbon footprints, what time scales are considered? How many years for nuclear, wind turbines, fracking etc.?" (George Field)

LS: "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."

24. "Is the #tech hype about renewable energy for real? Will these technologies 'save' us? #energypanel" (@SollertisS)

NMD: "As an academic, I'm not too familiar with 'tech hype'. However, renewable energy is becoming increasingly important to our energy system - whatever one's perspective on this might be. It is a fact that the incident solar energy on our planet is many, many times greater than our total energy demand. Therefore, it is clearly a good idea to try and harness as much of this energy as possible. That said, it is also important to acknowledge the limitations of these energy sources - for example, increasing the impact of intermittent renewable energy will require the large scale deployment of energy storage technologies (in a range of forms). It is also important to acknowledge the fact that this transition will not happen overnight."

25. "Can we harness the power of hot springs to heat homes?" "Yes Romans did it in Bath thousands of years ago." (@claudemmx2)

CG: "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."

26. "Here in #Yorkshire the declining mining industry is a raw issue. Which energy could utilise skilled labour most? #Energypanel" (@WRPsocial)

JR: "Any industry would welcome skilled labour. I know most about the nuclear industry and that is expanding as well as 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."

27. "Huge desert solar farms that could power the world are often mooted. How efficient (+likely to happen) are they?" (@WRPsocial)

CG: "Tricky. The big problem is that they need water (at least in their current form) and water is precisely what deserts don’t have. However, development is continuing – look at HERE which details two recently constructed big plants in the US. The advantage of these huge generating plants is that they can store the energy that they have collected from the sun and still produce electricity at night. But they are currently about twice or three times the price of ordinary solar panels. I’d go first for solar panels as long as we can find a way of cheaply storing power for periods when the sun isn’t shining and the wind isn’t blowing."



Our Q&As answer the questions people put, which may mean that some parts of a subject are covered well and others not. If there is an issue that you think is not tackled, you are welcome to send a follow up question to our energy panel