The UK needs to green it heat supplies - it can’t continue to use fossil gas. But there is a lot of debate over how. Electric heat pumps are the option favoured by many since they can use green power to upgrade ambient heat with very high efficiencies. One unit of power in can produce up to 4 units of heat out.
However, there are opponents, and not just from those like Reform UK with anti-green tech views. For example, although the Ecotricity-backed Green Britain Foundation accepts that, ‘well-designed and installed heat pumps can deliver substantial savings in CO2 emissions’ it says ‘there are significant risks in terms of running costs’ &‘capital costs are much higher than gas boilers.’ Specifically, ‘to deliver the same amount of heat via a heat pump would cost 24% more than a gas boiler,’ while ‘the capital cost of installing an ASHP, including alterations to the distribution system, is more than 4 times the capital cost of replacing a gas boiler. And it also said ‘some buildings are better suited to heat pumps than others.’
This didn’t go down well with Carbon Brief. It. While it admitted that ‘heat pumps cost more to install than gas boilers’, it said there were overall cost savings: ‘the UK government’s recent “warm homes plan” says that they can help cut energy bills by “hundreds of pounds” per year. Similarly, Nesta published analysis showing that a typical home could cut its annual energy bill by £280, if it replaces a gas boiler with a heat pump, as shown in the figure.’
However, Carbon Briefs own data show that solar can save even more, which is one of the points raised by Dale Vince, Ecotricity founder- and Labour supporter. He told the BBC ‘Solar panels give us the biggest bang for buck there is no doubt about that - cheapest to install and most productive in terms of bringing down energy bills. Heat pumps sit at the other end of that scale. We could put solar panels on 10 million rooftops or heat pumps in one million homes.’
The debate goes on. And it can get bitter: there’s big money at stake in green heating. The UK has been slow to get going with heat pumps, in part since people didn’t know much about them or the grant system to support their uptake, but heat pump installation has gradually expanded - it’s up 27% this year. And with the Government finally releasing its Future Homes Standard, which effectively makes heat pumps (or heat nets) mandatory in new-build homes, resistance from house developers may have finally been overcome. Same for solar PV too.
Another big area of contention is the idea of using hydrogen for heating. There were plan for local test projects but they were halted after local opposition. And the idea has been downplayed as not yet viable in the new Warm Homes plan- it was seen as too expensive compared to heat pumps. It certainly is true that green hydrogen cannot be cheaper than the green power used to make it. But in the debate over hydrogen options there was a bit confusion between green hydrogen, produced using renewable power (quite expensive) and blue hydrogen (less so), produced by high temperature ‘steam reformation’ of fossil gas- with CO2 also being produced. So that’s not exactly green- but it is favoured by those who wanted to carry on using fossil gas, and also the old gas mains. But green hydrogen sometimes seems to have got tarred by the same brush.
However, though heat pumps seem to have won out for use in many locations, there are other ways of using hydrogen and some of them may prosper. For example, green hydrogen from renewables can be stored and then used to produce power again when green power supplies are low. A system balancing option. And some of that power could be used for heat pumps. It sounds a bit complicated, but DESNZ commissioned a report on hydrogen-to-power options (‘H2P’), and that looked quite positive, in terms of technical readiness and cost profiles.
It concluded that large scale storage was critical to align the profiles of low carbon hydrogen production with expected energy need, especially for ‘green’ electrolytic hydrogen, with salt caverns currently being seen as the proven and cost effective option to deploy at the pace required to scale up H2P. It noted that, from this year onwards, new gas-fired power stations were expected to be designed to be hydrogen-ready or carbon capture and storage-ready, but it said that, although turbines capable of running on 100% hydrogen were expected to be available in the early 2030s, they would still require natural gas for start-up. Interestingly, as an Osborne-Clarke summary noted, although fuel cells were potentially up to 10% more efficient than single-cycle turbines or engines, their current capital cost was two to three times greater than those of turbine based systems, which may limit their application. But otherwise H2P seemed viable.
However, hydrogen technology, in its various versions, is still moving a little slowly. A report in January from the UK Hydrogen Energy Association painted a picture of a hydrogen sector ‘eager to invest, expand and create thousands of jobs, yet increasingly frustrated by slow and uncertain policy delivery’. Dr Emma Guthrie, Chief Executive of HEA, explained: ‘This report shows a sector that is committed, capable and ready to deliver - but increasingly constrained by uncertainty over demand, policy design and delivery timelines. The question is no longer whether hydrogen has a role in the UK’s energy system, but how quickly we move from ambition to deployment. With clearer signals and faster delivery, the UK can unlock thousands of skilled jobs, attract investment and secure a leading global position’.
Is there anything else- in terms of heating? Most obviously the UK housing stock need an energy upgrade so that it doesn’t waste so much heat. The Warm Home plan is meant to help with that - perhaps aided using local labour. And on the supply side there are also some niche options. For example, heat nets, as now backed by the new Future Homes Standard, where available. Whatever the heat source, district heating is still in favour in some locations- delivering heat with low losses to local (urban) users. In some countries solar heat is also fed into to the local heat mains and even stored interseasonally. Geothermal heat is yet another possibility for heat nets in some places. And, finally, there’s biomass, wood stoves or biogas combustion units – small (home sized) or large (for heat nets). It can involve new CO2 release and it has land-use implication, but some see biomethane AD gas from wastes as more environmentally sound and as having a large UK potential. especially given current fossil-gas issues.
Plenty of possibilities then, with a range of uses, costs and also environmental implications…and all of this also needing to be integrated fully with the rest of the emerging green energy system. Lots to get right.
No post next week: I am having an Easter break.
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