Transform gas to decarbonise heating and hot water in the UK.
Discussion of what measures must be taken to decarbonise our electricity generation and use continues. But much less is heard of the other big decarbonisation imperative: the 47% of final energy consumption that is used for heating. Overall space heating and hot water contribute 15% or so of Britain’s greenhouse-gas emissions. This is likely to remain unchanged for some time, since overwhelmingly mineral gas remains at the heart of the energy used in heating systems: 80% of all domestic heating and hot water is supplied through gas boilers.
The official government line on decarbonising heat has been to dissolve the problem by electrifying it – replacing all gas boilers over 30 years with electric heating and hot water supplied by heat pumps. There are two main problems with this: first, in order to match the wide range of heat demand over the year, electricity capacity would probably have to more than double; second, the entire gas network and boiler systems would have to be scrapped at great expense.
The official estimates are that some eight million heat pumps would need to be installed by the early 2030s. This would be some achievement, bearing in mind that now only a few thousand are installed each year. Although there may be a role for heat pumps and electrification, the scale of the challenge suggests this plan is unfeasible. So what is the alternative?
There is an interesting glimmer of something else taking shape in the latest government consultation on the future of the Renewable Heat Incentive, the main instrument to support heat decarbonisation. Although there is a continuing emphasis on supporting heat pump installation, the consultation at least recognises that green gas – the production of biomethane and similar low carbon gases from organic waste – can play an increasing role in decarbonising heat.
This is beginning to happen. Two years ago, just one plant was injecting biogas into the gas grid. Now there are 50. The explicit encouragement of these plants in the new consultation, underfunded though it is, could kick-start an entirely different way of looking at the problem of the predominance of gas in heat systems: in short, don’t fight it; but transform it.
