We are familiar with established trends in the electricity industry towards more renewable and decentralized generation, plus storage and a smarter grid. But how does an industrialized country go about decarbonizing its heat sector?
Particularly the UK, with its stringent emissions reduction targets and a government committed to meeting progressively reducing carbon budgets established by its own Committee on Climate Change (CCC)? By law – the 2008 Climate Change Act – Britain has to cut its carbon emissions by four-fifths, on 1990 levels, by 2080, and by half within the next ten years.
Some clues emerged in the presentation at a recent conference on heat from CCC chief executive Matthew Bell, who started by stressing the overriding importance of the residential space and water heating sector, which is mostly based on natural gas. In the next three or four decades, gas boilers will have to be replaced by some combination of heat pumps, low carbon district heat networks and, perhaps, hydrogen, said Bell.
Direct electric heating could also be used, once the grid has been decarbonized through renewables, gas with carbon capture and storage (CCS) and nuclear power. So how about nearer-term targets?
Well, by the mid-2020s, Britain is going to have to take some decisions on the future of the natural gas network – could it be scaled down and repurposed for hydrogen? How much biomethane might be available? Meanwhile, it should be relatively easy to make homes more energy efficient, so they use less heat; to roll-out many more heat pumps; to build all new homes to a very standard (to avoid costly retro-fitting); and to develop more heat networks in high density parts of towns.
Current CCS scenarios show 15% of homes and half of commercial and public buildings using low carbon heat by the early 2030s, and the large parts of the existing gas network no longer in use. Hydrogen and heating networks would take their places alongside a curtailed gas distribution system.
If any of this comes to pass, it will be quite a revolution – individual gas boilers are by far the dominant energy technology for UK homes, and the domestic sector is notoriously difficult to influence. Such radical change may look unlikely today, but the pace of change in the UK electricity system has surprised many people – and solar PV installation rates continue to accelerate. Perhaps the UK is on the cusp of a major reduction in the use of gas and gas boilers in its domestic sector.