The UK's future energy mix
What will it look like if we're to reach Net Zero?
"We have lots of solutions,” says Professor Tim Green, Co-Director of Energy Futures Lab at Imperial College London, “but there are some uncertainties over which is the right one. It’s almost as if we face a sort of decision paralysis. If we don’t know how we’re going to decarbonise, then the temptation is to do nothing… but we have to get moving.”
Green is referring to the deadline to decarbonise which was set out in June 2019, when the UK parliament passed legislation which required the government to bring all greenhouse gas emissions to “Net Zero” by 2050. In other words, in less than thirty years from now, the UK is legally bound to no longer add more greenhouse gases to the atmosphere than it removes.
If we don’t know how we’re going to decarbonise, then the temptation is to do nothing… but we have to get moving.
This mammoth challenge would be enough to explain Green’s sense of urgency on its own, but we are already not on track to meet this target. So, in November 2020, Prime Minister Boris Johnson produced an ambitious Ten Point Plan for a so-called “Green Industrial Revolution”. It covers a wide range of technologies, including a quadrupling of offshore wind capacity, accelerating the uptake of electric vehicles, expanding low carbon hydrogen production and use, advancing nuclear power, and aiming to become a world-leader in carbon capture and storage. The plan commits £12 billion of government investment to create and support 250,000 “green jobs” in those technologies.
The Ten Point Plan was part of a larger Energy White Paper – the first of its kind to be published since 2007, and launched at Imperial – which set out the government’s agenda for energy and tackling climate change. And it is timely for the UK to be focusing on energy now: the paper paints the COVID-19 pandemic as an opportunity to re-grow as a greener economy; Brexit has forced a re-examining of policy and regulation; and Glasgow is to host the COP26 – the UN’s Climate Change Conference – in November this year. Our country is at a tipping point and the arithmetic is simple: lower emissions into the atmosphere, and remove greenhouse gases from it to achieve Net Zero by 2050.
Professor Nigel Brandon welcomes Alok Sharma - then Business and Energy Secretary and current COP26 President - to Imperial in December 2020 to launch the government's Energy White Paper and hear about Imperial's Transition to Zero Pollution initiative
Professor Nigel Brandon welcomes Alok Sharma - then Business and Energy Secretary and current COP26 President - to Imperial in December 2020 to launch the government's Energy White Paper and hear about Imperial's Transition to Zero Pollution initiative
But the big question is: how?
The breadth of green technologies mentioned in Johnson’s Ten Point Plan illustrates the sheer complexity and size of the challenge ahead. There is no silver bullet to decarbonise our economy. Instead, the UK’s future energy system will be made up of a diverse menu of low-carbon and renewable energy technologies, all pulling together to meet the targets. The exact balance of technologies in this mix is yet to be determined.
An equally diverse team of experts at Imperial is stepping up to the task, from computer modellers to structural engineers, policy advisers to behavioural and social scientists. As a materials scientist turned professional science writer and lapsed hydrogen storage researcher, I was excited to speak to eleven of them from across the university to find out how Imperial is contributing to the UK’s ambition to achieve Net Zero by 2050.
The power of wind
First, I wanted to understand the green technologies at the centre of the UK’s future energy system. As a country fortuitously situated in a windy corner of Europe, the UK is perfectly placed to generate a lot of energy with wind turbines.
“Well, it’s the future. It’s actually the present, isn’t it?” says Professor Rafael Palacios from the Department of Aeronautics. He’s right; over recent decades, offshore wind farms have become commonplace along the south and east coasts of the country thanks to relatively shallow seas, and large onshore wind farms populate Scotland, Northern Ireland and the north of England. In 2019, the UK’s offshore wind farms provided 10 GW of power to the grid, and Johnson aims to quadruple this to 40 GW by 2030, which would be enough to power every home today.
Not only will expanding this capacity mean building many more wind farms, but Palacios’ team are researching next-generation wind turbine technology. They do this by simulating large-scale turbines which float on the surface of the sea rather than being anchored to the seabed. “That opens the whole ocean to us," he beams.
I’m very optimistic about wind energy.
It’s all done with advanced computer models. “There’s no way we can build a 200 metre wind turbine to see how it goes,” says Palacios, “so we do simulations. This is a humungous challenge – we have to go to the largest computers anywhere to simulate these. This is because we have to simulate the very large – the farms are huge, the Earth is huge! – and the very small, at the microscale of the blades, all at the same time. That means lots of computing power.
“But personally,” he continues, “I’m very optimistic about wind energy – the only reason we don’t power everything with wind turbines is that it’s intermittent, so we need to have a set-up in which there is a way to deal with fluctuations.”
These fluctuations arise from weather patterns – the wind doesn’t always blow and the sun doesn’t always shine when demand for energy is high. Currently, this isn’t too much of an issue; wind energy is fed directly into the grid, which is able to accommodate the fluctuations due to its relatively small proportion – in 2020 a quarter of the UK’s electricity was generated by wind. But if wind is to dominate the UK’s energy mix – as Johnson’s goal to quadruple offshore wind capacity aims to achieve – we’ll have to come up with a way to store that energy to regulate its supply.
Batteries becoming big
Dr Billy Wu, Senior Lecturer at the Dyson School of Design Engineering, believes the answer to this technological problem lies with batteries.
“I see energy storage in three different parts,” he says, “consumer electronics, which we’ve kind-of solved, electric vehicles where the challenge now is driving down cost, and large-scale grid energy storage.”
One form of grid-scale storage resembles large sites of shipping containers, housing vast numbers of lithium-ion batteries. In November 2020, the green light was given for the UK’s largest-ever battery storage project to be built at DP World London Gateway on the Thames Estuary, which could provide 320 MW of capacity to buffer intermittent renewables on the grid. It is scheduled to be operational in 2024, and a number of similar projects are planned across the country.
We don’t want to make the cheapest battery in the world for it not to be recyclable.
But there are still challenges to be overcome with this technology. “The lifetime of these batteries will be a problem,” says Wu. “You want them to last at least thirty years, but we’re struggling to make electric vehicle batteries that last even ten years... Another issue is that we need to think about recycling of the materials, otherwise we create new problems for ourselves. Right now, it’s still not economical to do; we haven’t got to the stage where we’ve got a large enough volume. But just like with plastics, where we perhaps didn’t design the infrastructure in such a way that we can handle them, we don’t want to make the cheapest battery in the world for it not to be recyclable.”
At Imperial, addressing these challenges involves developing new materials and types of batteries, including using computer modelling to accelerate this development, to find the best combination of materials and improve battery design. Researchers are also tackling the difficulties around fast battery charging and heat management.
The three different scales of energy storage – small electronics, medium-sized vehicles and large-scale grid-level storage – largely exist independently of each other today. But in the UK’s future energy mix, there will be interactions between these different scales of energy storage, where medium-sized batteries could perform the tasks of grid-level storage. This is the concept of Vehicle-To-Grid storage.
“If you’ve got a car, you might drive it ten percent of the day, if at all,” explains Wu. “In that other time, it could be doing energy services. It could be buying energy when it’s cheap and selling it when it’s expensive. In the future your car could help balance the grid’s supply and demand, and also generate revenue for you.”
But expanding the role of batteries in vehicles and on the grid will lead to other challenges. “The UK is planning to ban petrol and diesel vehicles by 2030. That’s a very aggressive target. Actually, the problem now is how do we make that volume of batteries fast enough?” says Wu. “To give you a sense of scale, one of the largest battery factories is the Tesla Gigafactory in Nevada. And that produces enough batteries for maybe 300,000 electric vehicles a year. In the UK, we would need approximately six or seven of these gigafactories for our grid-scale and electric vehicle needs. At the moment we don’t have any, really. So that’s going to be a real challenge.”
Feeling the heat
Green electricity generation and its associated storage is just one part of the energy puzzle. “We’ve done a lot of good work on reducing the carbon intensity of electricity in the UK,” says Christos Markides, Professor of Clean Energy Technologies at the Department of Chemical Engineering. “It’s a success story for the country. But we actually use a lot more thermal energy than we use electricity. Heat is the elephant in the room for the UK. We haven’t done nearly as much, and you can’t do everything with batteries… we need to decarbonise in a holistic sense. Net Zero means we have to start thinking about everything,” he says.
We need to decarbonise in a holistic sense. Net Zero means we have to start thinking about everything.
Markides works on technologies that involve a thermal component, such as heating and cooling buildings and the heat of industrial processes. “This means using technology to transform energy from one form to another. For example, you can use electricity to provide heat through heat pumps, or transform heat back to electricity through power stations,” he says. In other words, it’s easy to picture electricity flowing around a UK grid, but there is also another energy system superimposed on that grid, which involves the flow of heat. In practical terms, that currently manifests as our domestic gas grid used to power home boilers and cookers, along with gas-fired power stations which turn heat into electricity.
Going nuclear?
But another green option for heat energy is nuclear power, a technology highlighted in Johnson’s Ten Point Plan. “Nuclear has been supplying lots of low carbon energy for over sixty years, day and night, foul weather or fine,” says Professor Robin Grimes, BCH Steele Chair in Energy Materials in the Department of Materials. “Currently, all the heat produced by nuclear power stations is turned into electricity, but this doesn’t have to be the case.”
By switching from electricity for the grid to supplying other products, nuclear can compensate for the intermittency of renewable electricity.
Nuclear power stations of the future will be more flexible to the system’s energy needs. “When the need for electricity is high, the heat created in a nuclear reactor can be used to generate electricity. When it’s low, nuclear heat and/or nuclear electricity can be used directly in industrial processes to generate chemicals, including hydrogen and synthetic fuels. This is known as co-generation. By switching from electricity for the grid to supplying other products, nuclear can compensate for the intermittency of renewable electricity,” says Grimes.
Future nuclear power stations will likely take the form of small modular and advanced modular nuclear reactors, which offer the flexibility required in the renewable-heavy future energy mix. “These new reactors will also offer tremendous opportunities for UK manufacturing engineering,” says Grimes, “but the government needs to offer its support to attract the required investment.”
Dr Adam Hawkes is Director of the Sustainable Gas Institute at Imperial
Dr Adam Hawkes is Director of the Sustainable Gas Institute at Imperial
Heating with hydrogen
These opportunities brought by nuclear power highlight an often-forgotten component of the energy system: high-energy industrial processes, such as those for making steel, glass and cement. “Low-carbon industry is a really interesting area,” says Dr Adam Hawkes, Reader in Energy Systems in the Department of Chemical Engineering. “People don’t know a lot about it - even the research space is relatively sparse on industry decarbonisation.
“I think hydrogen potentially has a role there; industry has a whole bunch of uses for hydrogen and it can be produced very low carbon through electrolysis [splitting water into hydrogen and oxygen using electricity] or through carbon capture and storage,” says Hawkes. There has also been great progress in using hydrogen to replace liquified natural gas as a clean fuel for industrial processes such as steel-making, achieved by Swedish steel maker Ovako in 2020. Johnson included the expansion of low carbon hydrogen in his Ten Point Plan.
“Hydrogen can also be used in buildings - for heating and hot water,” continues Hawkes. And this is where another energy system change will play out: local energy systems will develop which divide up the national system into a network of highly-attuned local ones, which play to each region’s strengths and energy needs.
Hawkes illustrates: “There’s an initiative to develop industrial clusters around the UK. Here you might have large-scale hydrogen production powered by local renewables such as wind and solar which is very low carbon, and use it in local industry. You could also perhaps feed some nearby areas with hydrogen for heating buildings.”
Having hydrogen in our homes is not as far-fetched as it sounds – a 2016 report by Northern Gas Networks assessed whether it would be possible to convert the city of Leeds to 100 per cent hydrogen instead of natural gas, and likened the task to the successful nationwide conversion from town gas to natural gas in the 1960s and 70s. Boiler manufacturers are starting to produce ‘hydrogen-ready’ boilers in anticipation of a future fuel shift.
Balancing the carbon equation
It is unlikely that it will ever be practical to eliminate all carbon dioxide emissions from industry, but various chemical processes can be integrated into existing industrial processes to capture it, tipping the emissions equation closer to Net Zero. Once the gas is captured, it can be compressed into a liquid, and pumped deep underground into a stable geological formation to be stored there indefinitely.
This is Carbon Capture and Storage (or CCS), and is the research topic of Paul Fennell, Professor of Clean Energy in the Department of Chemical Engineering. “The technology has been around for twenty years,” he tells me. “The Sleipner gas field in Norway is a good example, and there are a few other demonstrations of CCS around the world, but none in the UK.”
This absence of CCS in the UK, he says, is all down to the high cost of the technology compared to renewables. But Johnson’s Ten Point Plan points to new ambitions – to make the UK a world leader in CCS. And compared to other countries, the UK is relatively well-positioned to embrace this technology. “We’re lucky that we can just put it under the North Sea,” says Fennell.
A whole system view
These conversations about the technologies have left me with the impression that the UK’s future energy mix will be an intricate balance, complex and ever-changing. Yet all of the experts agree that we need to act urgently with big and bold building and investments if we are to stand a chance of achieving Net Zero. With so many slippery permutations of a potential technological mix, how can we hope to move forward with any sort of confidence?
This is where Imperial’s IDLES programme comes in – Integrated Development of Low-carbon Energy Systems.
“It’s a whole-system view of energy,” Professor Tim Green, Co-Director of Energy Futures Lab and IDLES principal investigator, tells me. “That means trying to account for what goes on in people’s houses and the places where they work, up through the local energy networks to the national energy networks, and some view also of the international exchanges, how we link to our neighbouring countries.
Professor Tim Green explains how IDLES researchers are developing a set of models to help plan the UK’s future energy system.
“We largely use computer modelling to understand how all the bits of the jigsaw come together,” Green continues. “We’re trying to work out what we need to build over the next ten to twenty years to help the UK hit the Net Zero targets. Right now, our modelling says we need to build two to three times as much off-shore wind as the government’s target – which already is highly ambitious at quadrupling capacity to 40 GW.”
We largely use computer modelling to understand how all the bits of the jigsaw come together.
And the IDLES models don’t just focus on carbon targets, according to Professor Nilay Shah, Head of the Department of Chemical Engineering. “IDLES looks at where the UK energy system can evolve from where it is today into a smarter, low-carbon system which is helping to deliver the other things we hope to see in the country, like regional development, maintaining an industrial base, economic development, a good quality of life and better air quality,” he says.
The IDLES models show that we can expect to see energy managed at a more regional level in the future. “We’ll see slight variations in different parts of the UK in terms of the local energy system flavour, relating to the availability of resources, local strategies and so on. For example, we might see more electric buses in London but more hydrogen buses in the north of England and Scotland, maybe, just because of the way the infrastructure might evolve,” explains Shah.
"I work at the confluence of
psychology, sociology and
engineering, modelling demand
for energy resources in a way
that reflects the daily
decisions and choices that
individuals and
households make."
Dr Aruna Sivakumar
Supply and demand
One common theme materialising through my conversations with experts is the increased role of the consumer in the UK’s future energy mix. Many of them have warned that the decisions we make and behaviours we live by could actually be the difference between meeting the targets or not. This is the research area of Dr Aruna Sivakumar, Senior Lecturer in the Department of Civil and Environmental Engineering.
“I work at the confluence of psychology, sociology and engineering, because I try to model demand for energy resources in a way that reflects the decisions and choices that individuals and households make in order to fulfil their daily needs,” she says.
“Actually, the idea of modelling human behaviour is something that’s not new to social science; all of your dating apps are based on models of how people behave and what their preferences are. Applying it in engineering has been a steep challenge. I think people who model infrastructures find it difficult to imagine that you could model human behaviours. But actually, there are uncertainties in both, and they’re just dealt with differently.”
What we do as social scientists and economists is to try to think about how people’s behaviour will affect energy demand when it comes to new energy technologies.
This means that how and when consumers use energy will change in the future, to become more flexible, depending on our demand for it. No longer will we be passive energy users, but we may have to make decisions and become active agents in the system. This new dimension is inextricably linked not only to human behaviour but economics, an area which Dr Mirabelle Muuls, Assistant Professor in Economics at the Imperial Business School, researches.
“What we do as social scientists and economists is to try to think about how people’s behaviour will affect energy demand when it comes to new energy technologies”, she says. One example is demand shifting; “Let’s say I turn my smart dishwasher on by saying that all I want is my dishes cleaned by tomorrow morning. The energy system can then talk to my dishwasher and make sure the dishes are cleaned when I need them but uses energy at the moment of the night where it’s cheaper and greenest.
“The problem is,” says Muuls, “we don’t really know how people will interact with these devices, and whether they are ready to embrace them or might need to be compensated as a user to automate this energy consumption choice.”
Watch Dr Mirabelle Muuls discuss her research on the economics of climate change and the impact of climate change on businesses. Credit: Grantham Institute
Muuls’ work aims to answer just those questions, and she stresses that it’s potentially a worthwhile cause to get right. “While a dishwasher does seem small, if you add up all the small devices it’s a big effect. For example, if you aggregated all UK fridges, and if they all turned on at the same time, that’s enough for one nuclear power station to turn on. So, by automating devices at the small level, you’re potentially making a big difference.”
Changes to policy
To make the biggest difference of all, this research at Imperial cannot exist in an academic bubble. Findings like those to come out of the IDLES programme must be communicated to policymakers, because not only will our energy technologies have to change to meet Net Zero, but so too will associated policies and regulations. This is the research area of Dr Madeleine Morris, Research Associate at the Grantham Institute - Climate Change and the Environment.
One roadblock is that policy is separated into different departments in government. Going forward all of those boundaries are going to become really blurred. They need to take a whole system view.
“Our old policies and regulations had large centralised high carbon systems in mind, and so there are some that aren’t quite fit for purpose any more. I’m looking at the policies and regulations of today through the lens of future smart and local energy systems, and figuring out where there might be tensions, where things might need to change, and how we can do that.”
Dr Madeleine Morris is Research Associate at the Grantham Institute - Climate Change and the Environment.
Dr Madeleine Morris is Research Associate at the Grantham Institute - Climate Change and the Environment.
The Energy Revolution Research Consortium (EnergyREV) brings together 60 researchers from 22 institutions from across the UK, including Imperial. It was set up in recognition that policymakers don’t have the evidence they need to support potentially revolutionary changes in energy markets, for example consumers becoming active agents in vehicle-to-grid energy storage. “Part of this programme is to get that sort of evidence out of pilot projects, and make informed recommendations to policymakers to influence policy going forward,” Morris tells me.
But it won’t be easy. “One roadblock is that policy is separated into different departments in government. Previously, electricity regulations were different from gas regulations, which were different from heat and transport… going forward all of those boundaries are going to become really blurred,” warns Morris, “they need to take a whole-system view.”
"I’m a strong believer that,
encouraged by the younger
generations, there will be
this movement, and it will
be strong enough."
Dr Mirabelle Muuls
Looking forward
Meeting the UK’s Net Zero target therefore hangs in the balance of technological advancements, bold investment, public compliance and cross-department policy. And so we return to Professor Tim Green’s initial warning; “We have lots of solutions… but we have to get moving.”
I think the biggest roadblock is the desire to do things incrementally. At some point you’ve got to make some quite big decisions.
Nilay Shah agrees, “I think the biggest roadblock is the desire to do things incrementally. At some point you’ve got to make some quite big decisions and start doing some big energy transition stuff. Whereas we’re always very comfortable just to add a bit more renewable energy, do a bit of that and a bit of this… we actually need some really big projects quite quickly.”
“I have some faith that emissions reductions will proceed to quite a low level,” says Adam Hawkes. “Achieving Net Zero, I think, is something else. Knocking out the last emissions from the system is going to be much more challenging than people anticipate. And if you look at the global emissions required to hit the Paris Agreement, they require net negative emissions for most of the second half of the century. The UK hitting Net Zero is nowhere near enough. You’ve got to keep going into negative emissions, and then you’ve got to convince the rest of the world to go with you.”
Despite these monumental challenges, many of the experts shared confidence and hope in the UK’s future energy prognosis. “I’m very optimistic because it’s in my nature,” says Muuls. “I’m a strong believer that, encouraged by the younger generations, there will be this movement, and it will be strong enough.
“There are lots of lessons that we can learn from the COVID-19 crisis,” she continues. “In a way, for all the traumatic things it has brought, it has also shown that if we listen to the science and plan properly then we can solve things and people can come together and find solutions. Hopefully, if we don’t leave the poorer countries behind, then we can achieve that. But it’s a huge challenge; making sure that you get sustainability and poverty solved… and one can’t go without the other.”
The Forum is Imperial’s policy engagement programme. It connects Imperial researchers with policymakers to discover new thinking on global challenges. Our features provide a shop window into the world leading research taking place at Imperial and provide insight into how it can inform and contribute to public policy debates.
Built with Shorthand