The UK transition is often cited as a success story. Coal’s contribution has dropped from 40% to 6%. Wind, solar and hydroelectric now generates more electricity than nuclear. Demand for electricity has also fallen. The carbon intensity of Britain’s electricity has almost halved, from over 500g of CO₂ per kilowatt-hour in 2006 to under 270g in 2018. The National Grid now expects to be able to operate a zero-carbon electricity system by 2025. But of the total UK energy supply more than 80% still comes from fossil fuels. Energy demand is rising again. 100% electric transport will need twice the UK’s current electricity capacity. During winter, heating requires over three times what electricity generators can produce today. Andrew Crossland and Jon Gluyas of Durham University look at what needs to be done to make 100% low-carbon energy a reality.
Progress has been so quick that a fully low-carbon power sector in Britain has transformed from a faint pipedream into a real possibility, according to the CEO of one of the UK’s “big six” energy companies. Indeed, the National Grid now expects to be able to operate a zero-carbon electricity system by 2025.
Already approaching that milestone on windy, sunny days, the country’s first hours of 100% low-carbon electricity could soon be here – but staying at 100% throughout the year will be much more difficult to achieve. So what does the journey to decarbonisation look like?
Headwinds to decarbonisation
To paint the UK’s energy future, it is important to first understand how electricity is generated today. The graph below is a visualisation of British electricity generation in October 2018. Periods of strong wind (in red) and sun (yellow) combined with nuclear power (green) meant that on some days, more than 75% of electricity came from low-carbon sources. With solar prices still decreasing and the government recently agreeing a major deal for offshore wind to produce one-third of the UK’s power by 2030, the country’s first hours of low-carbon power could arrive within the next five years.
But the graph also highlights the other side to the UK’s energy story. When the wind is weak and the skies dark, low-carbon sources provide less than 25% of electricity generation. On average, low-carbon technologies accounted for more than 45% of British electricity in 2018 – and almost half of that came from nuclear plants. Saying goodbye to fossil fuels quickly might mean accepting that the ever-controversial form of energy will play some role in the UK’s electricity mix in the medium term.
Even with the aid of nuclear power, electricity consumption in Britain is set to increase dramatically in the coming decade. As electric cars continue their journey to the mainstream, traditional transport fuels will be replaced by electricity. The yearly energy demand of transport fuels is currently more than double the UK’s national electricity consumption.
Similarly, plans to decarbonise the UK’s heat generation – currently 66% is generated by gas – by converting to electric heating systems will also place huge pressures on demand. During winter months, heat can consume more than three times the daily energy demands of electricity – and over a full annual cycle it constitutes 50% of total energy demand. Collectively, these factors will move the goalposts for 100% low-carbon electricity further and further away.
While the huge efficiency increase of electric vehicles over internal combustion engines should cushion the impact of electric vehicles on the UK’s energy future, the country will need to diversify its energy mix as much as possible to bring those goalposts back into sight. This means continued growth in wind, solar, hydro, biomass, energy efficiency and energy storage to carry the country through the calm, grey days. Precisely how much growth is needed depends exactly on the future of energy demand, but to give some perspective of scale, more than 80% of the total UK energy supply, including electricity, land transport and heat, still comes from fossil fuels. The tens of billions of pounds already invested in low-carbon electricity is just the start of the UK’s journey to decarbonised energy.
It also means seeking alternative, non-electric methods to replace fossil fuels in heat generation. Capturing waste heat from industrial processes, geothermal heat from the ground and heat extracted from water bodies could all limit demands on the electricity sector and make it easier to achieve more low-carbon heat and power. Southampton already heats much of its city centre geothermally – and many cities can and should follow suit. Recent work published by BritGeothermal estimates that geothermal energy alone could meet the UK’s heat demand for at least 100 years.
Concerted and sustained effort from both government and individuals is required if the UK is to achieve a low-carbon nirvana in heat, transport and power. State support of the renewables industry through ensuring long-term investment security and regulations to create energy-efficient and electricity-generating new homes will be essential in the UK’s decarbonisation journey. The UK population will need to consume less energy individually, use energy more efficiently and use their voices and money to support renewable solutions. They will also need to elect representatives with a genuine ambition to decarbonise the country – rather than to commission new coal mines and fracking sites.
Large-scale changes are already in motion. Shell recently stated that it wants to become the world’s largest electricity supplier and is among many oil giants investing heavily in renewables. While the need for new forms of energy presents big challenges for the UK it also offers a wealth of opportunities for the current generation to be part of an energy revolution. If the UK embraces the task, it could be joining Costa Rica, New Zealand and Norway as low-carbon powerhouses before the middle of the century. As one specialist at the start of his career and another nearing the end of his, we say bring that challenge on.
Andrew Crossland is Associate Fellow, Durham Energy Institute, Durham University
Jon Gluyas is Professor of Geoenergy, Carbon Capture and Storage, Durham University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Danny Hall says
Excellent article. And the fact that “more than 80% of the total UK energy supply still comes from fossil fuels” really jumps out at you after reading all the good news about the increasing use of alternative sources of energy. Let’s hope there are enough economic and political incentives to continue the positive growth and reach the 2025 target of zero carbon electric system.
jeremy bowden says
Why no mention of hydrogen? I think you are a little behind the curve. See http://www.tellingsense.com/blog/interview-with-dr-klaus-dieter-borchardt-director-internal-energy-market-dg-energy/
William H Smith says
The statement above “While the huge efficiency increase of electric vehicles over internal combustion engines should cushion the impact of electric vehicles on the UK’s energy future” is misleading. That would almost be true if wind (PV is practically useless in the UK) performed at 100% capacity factor, but the real number is under 25%. The wind turbine will not directly produce CO2, but the efficiency for electricity production is still only 25%, worse than the Rankine cycle efficiency for electricity from a Light Water reactor of around 35% efficiency. The molten salt high temperature reactor will reach over 60% efficiency, and produces NO CO2, if decarbonization is your goal.
Transmission of electricity to a charging station, then charging a battery, reduces the efficiency by another 10 -15%. Put these losses together, and the 90% efficient electric motor energized by a battery storage device of your choice, is less efficient, by a large margin, than a good hybrid such as the E300 Mercedes which achieves a 67 mpg EPA rating that is verifiable, while the Tesla’s high rating which considers ONLY the battery’s stored energy, not from where it came, drops to 32 mpg.
ALL the electricity resources, considering the capacity factors which are another word for inefficiency, must be OVERBUILT to compensate for the deficit, and to store energy against the months in which wind is low, not to mention the days to weeks when it is off altogether.
Since it is demonstrable that nuclear power is the safest form of energy on the planet, as already understood by David MacKay back in 2006 (Sustainable Energy without All the Hot Air), it is impossible to understand the frame of mind leading Britain into an energy deficit and into energy poverty.