Decarbonising heating in Britain

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An abridged version of this article appeared in Extinction Rebellion's newspaper "The Hourglass" issue 3 / November 2019 under the title: "Staying warm in a house on fire".

Paradoxically, global heating is likely to result in colder winters in the British Isles for some decades to come, as the temperate Gulf Stream falters[1][2], and disruption to the polar vortex unleashes the Beast from the East[3]. Burning yet more fossil fuels to stay warm is the last thing we need but, even if Carbon emissions were no problem, this is particularly bad news since British housing and heating systems are built for our relatively mild winters and are no match for the temperatures our neighbours in continental Europe experience – and build for – which can drop tens of degrees below freezing[4]. On top of that, gas supplies can struggle to keep pace with peak demands[5].

For those already suffering from poverty in the UK[6], the combination of extreme cold weather with fuel poverty and poorer quality, harder to heat housing, will cause yet greater hardship, ill-health, and – for some – death. Not to mention the plight of Britain's tens of thousands of homeless rough sleepers[7].

We can do a little to help reduce our fuel use (and bills) by putting on warmer clothes instead of turning up the thermostat, by shutting doors and windows, blocking up draughts etc[8], but personal efforts can only help marginally. The big changes have to be made at government levels, but they’re not easy.

Heating consumes more than half the energy we use in our homes[9], and about a third of the energy we use nationally[10], and most of that is CO
-emitting gas and oil. How can we decarbonise our heating?

UK final energy consumption 2009 (DECC).jpg

The challenge of decarbonising all of Britain's energy – including heating – was addressed by David MacKay in his classic Sustainable Energy Without The Hot Air, in which he discusses not only the various technologies available for moving to sustainable energy, but the physical potentials and limitations of different technologies, and how we can devise plans (that add up!) for balancing supplies with demand.


There are reckoned to be 26 million gas boilers in the UK.[11] The Climate Change Council wants a ban on gas boilers in new houses[12] and, with improvements in building regulations, houses could be built which require practically no heating (or cooling) at all[13], or their modest needs could be met using heat pumps. However, new houses are only a tiny proportion of all our housing, and most existing buildings were built to far poorer standards. Improving their insulation and draughtproofing can significantly reduce their heating demands, but nowhere near enough to eliminate the need for heating at all.

Electrifying heating

Could we replace oil and gas boilers with electric heating - perhaps using heat pumps? In France a lot of heating is electric, but they practically decarbonised their grid decades ago with cheap, low-carbon nuclear electricity[14]. In Britain we’re not even on course to replace our existing nuclear power stations as they reach the end of their lives[15], let alone to massively expand our clean generation capacity. Wind provides useful amounts of clean electricity (although solar is little use in the winter, when demand is highest[16], and other clean renewables are limited in potential and, as yet, poorly developed). We can also decarbonise our fossil- and biomass-fuelled power stations using carbon capture and storage, but we still have a huge job to even decarbonise our existing electricity supplies. Generating lots more clean electricity for heating (and upgrading grid capacity to get all the extra power to where it’s needed) would add further to the challenge[17]. Not to mention that electric boilers and heat pumps are very far from being a drop-in replacement for the common domestic combi boiler[18].


Wood-burning stoves or biomass boilers are an even less practicable alternative to domestic boilers, even if we had an unlimited supply of fuel, although biomass boilers can provide an effective alternative to fossil fuels for larger buildings where fuel supplies are available[19].


An approach being tested in the North of England[20] is to decarbonise our gas network. Natural gas coming ashore from the North Sea would be split into Hydrogen and Carbon Dioxide by a process known as Steam Methane Reformation (SMR)[21]. The CO
would be pumped back into disused gas reservoirs deep underground while the Hydrogen would be fed into the existing gas pipe network (and salt caverns for temporary storage) to feed modified cookers and boilers in homes and businesses.

Schematic of H21 project

It would require a massive conversion effort, but we did something similar between 1968 and 1976 when we converted from town gas (which was a mixture of mostly Hydrogen with deadly Carbon Monoxide) to “North Sea Gas”.[22]

Converting the grid to Hydrogen could have the extra benefit of making Hydrogen readily available for uses such as decarbonising rail[23] or even some air transport[24].

Also, having a national Hydrogen network with some storage capacity available could help with the problems of integrating larger proportions of variable renewable energy (VRE) such as wind and solar, and baseload capacity such as nuclear, into the electricity grid. At present when more energy is being generated than is needed some has to be thrown away, but it could be used to split water by electrolysis to generate Hydrogen, which could then be fed into the gas network. (Converting electricity to Hydrogen in this way is quite inefficient, but is probably better than wasting it[25].)

Politics, and beyond

Whatever approaches this country chooses should be informed by the appropriate science, engineering, economics and other experts. However the necessary actions are likely to have significant effects on the public, and need popular support to be accepted. In our current political system we have, at national level, as little as one vote every five years, and for many of us those votes are rendered practically meaningless by our antiquated "first past the post" voting system. History shows that although we have had more than 30 years clear warning[26] of the issue of CO
-induced global heating, successive UK (and international) governments have done little or nothing about it[27]. Furthermore the momentum for action tends to have been subject to the priorities of the government of the day, whilst the climate crisis has continued to escalate without regard for political whims and expediencies. We need a way of getting effective actions on climate and sustainability problems; actions that represent the informed consent of the public, and aren't subject to the short-term restrictions of 5-year governments and the ideologies and compromises of party politics.

The approach demanded by Extinction Rebellion is that the government should set up a genuine[28] Citizens Assembly, representative of all sections of society and with enough time and resources to make well-informed decisions on behalf of the country as a whole, binding on the government to enact.

Further reading

Policy Connect, which describes itself as "a cross-party think tank", has produced a report: "Uncomfortable Home Truths: why Britain urgently needs a low carbon heat strategy" (PDF) on the challenges, and possible approaches to decarbonising UK home heating. The report discusses not only technical aspects such as insulation, heat pumps, district heating schemes, and hydrogen boilers, but also issues of how they can be paid for, fuel poverty, and public acceptance.

The report envisages the involvement of citizens' assemblies (or juries), but merely as part of "engagement, acceptance and awareness raising"[29], suggesting that the CA's role should be just to sell an already worked out package of technologies, pricing and timescales, rather than to determine such factors.

The Energy Research Partnership has also published reports on its work, including heating buildings, the use of Hydrogen to decarbonise the UK's energy, and decarbonising Electricity.

Footnotes and References

  1. "Avoid Gulf stream disruption at all costs, scientists warn", Damian Carrington, The Guardian, 13 Apr 2018
  2. "Is the Gulf Stream about to collapse and is the new ice age coming sooner than scientists think?", Josh Gabbatiss, The Independent, 12 Apr 2018
  3. "What is the polar vortex – and how is it linked to climate change?", Oliver Milman, The Guardian, 31 Jan 2019
  4. "UK homes unfit for the challenges of climate change, CCC says"; Climate Change Council; 21 Feb 2019
  5. "Gas consumption during the ‘Beast from the East’", UK Energy Research Centre (UKERC), 17 Aug 2018
  6. "Inequality and poverty in Britain", Cambridge Institute for Sustainability Leadership, Dec 2018
  7. "Homelessness in the UK" Wikipedia
  8. A dated (2008) but still useful guide to energy saving is "Cost-effective ways to reduce your carbon (CO
    ) footprint
    " by Sandy Polack,
    and the Energy Savings Trust has a guide to how much money various behaviour changes can save.
  9. "The UK Housing Context", Jonas Rooze, Carbon Descent blog, 18 May 2011.
  10. Figure cited by David MacKay in his TEDx talk "A reality check on renewables".
  12. "UK homes unfit for the challenges of climate change", Climate Change Council, 21 Feb 2019
  13. For example Tony Cowling's house in Reading.
  14. "Nuclear power in France", Wikipedia
  15. "Nuclear power in the United Kingdom", Wikipedia
  16. The amount of energy supplied by solar PV in Britain over a year can be seen from this display from Sheffield University's Live PV generation web pages: Power supplied to from solar over a year
  17. Britain's gas consumption during the "Beast" peaked at over 200Gw, whereas the whole of our electricity supply is about 50GW: see "Gas consumption during the ‘Beast from the East’", UK Energy Research Centre, 17 Aug 2018
  18. Heat pumps produce far lower temperatures than gas and oil boilers and can't produce sufficient heating with existing radiators, which need to be replaced with bulky fan-assisted radiators or, ideally, Under-Floor Heating (UFH). They require a large fan-assisted heat exchanger out-doors, connected by pipework to an indoor unit, which can pose problems for siting. And a heat pump capable of producing hot water on demand would generally be much bigger and more expensive than one just for space heating (e.g. combis have power outputs of at least 24kW in order to supply hot water at reasonable rates, but a small house or flat may only require half that power for space heating), so domestic hot water is usually provided by a fairly bulky hot water cylinder, which adds to the challenges of fitting everything in, especially in small houses and flats.
  19. For example this installation at a community-owned country house and estate in rural Oxfordshire.
  20. see article on the H21 North of England project
  21. This process loses between a quarter to a third of the energy embodied in the methane gas, see e.g. this "Hydrogen Fact Sheet" from US energy consumer site and "Fuel Cells" by Hamdi Abdi et al in Distributed Generation Systems, 2017, excerpted on Science Direct
  22. "Gas industry timeline", National Gas Museum website
  23. e.g. the Hydroflex project for running trains on Hydrogen on parts of the rail network, such as rural routes, which have not been electrified, as described in this article in Gas World and this from the BBC
  24. e.g. this experimental light aeroplane
  25. assuming that the value of Hydrogen produced is greater than the cost of building and maintaining the (intermittently used) electrolysis plant.
  26. In 1988 James Hansen testified to a US Senate committee that "Global warming ... is already happening now" [1], and in 1989 Margaret Thatcher warned the United Nations about global climate change, deforestation, pollution, and other man-made dangers [2]
  27. The Climate Change Act 2008 [3] mandated an 80% reduction in emissions by 2050, which was thought at the time to be sufficient to tackle climate change effectively, but we are not even on track to achieve that target.
  28. A Citizens' Assembly is being set up by six Select Committees of the House of Commons [4], to "explore views on reaching net zero emissions by 2050", but it will only have 4 weekends over which to deliberate, and its results will "feed into future Select Committee work, as well as informing political debate and Government policy making" rather than being mandatory on the government to implement.
  29. See page 10, section 2.c, and item in the graphic split across pages 12-13 "From 2021: Develop processes for monitoring and integrating public attitudes into policy-making, including using processes like citizens assemblies"