Heat pumps can end our reliance on fossil fuels
As we see record temperatures, scientists are panicking that feed-back loops in the ecosystem means climate change is happening faster and more unpredictably than in their worst nightmares.
Achieving net zero rather than talking about it is extremely urgent.
Heating accounts for around 25% of the UK’s annual carbon footprint. Most of that is through burning gas – it needs to go.
Some believe Hydrogen is a get out of jail free card. But none of the serious research agrees. It would be wildly expensive (it takes six units of electricity to get one unit of hydrogen). It is dangerous – molecules a tenth the size of gas can leach through metal. Worse, there is no odorant for hydrogen that allows you to smell a leak. Every pipe in every home and street has to be made safe for hydrogen, and the day gas is switched over every ‘hydrogen ready’ appliance in every home needs an engineer switch out gas parts for hydrogen ones (hydrogen ready being a misnomer).
That’s why the Committee for Climate Change says the UK must embrace the electrification of heat. Thankfully, unlike hydrogen, heat pumps work today, are safe, and reduce bills (one unit of electricity delivers 3 to 4 units of heat with Ground Sourced Heat Pumps).
But how to get them affordably into every home? Here, the history of gas replacing coal fires is instructive. The key was that gas pipes were installed in the street – so every house could easily and cheaply hook up to the network.
This is the only model that could affordably replace coal. For the same reason a street by street utility is the only model that can replace gas for every home. How does that work for heat pumps? The answer is Networked Ground Source Heat Pumps (GSHPs), pioneered by a British company called Kensa, and already heating thousands of houses and flats.
Networked GSHPs replicate the gas network in the street, with a street ground array taking the ground temperature to your home where it is boosted by your own heat exchanger called a heat pump - a little white box in the house similarly sized to your gas boiler but running on electricity.
Science fiction? This approach is already delivering the lowest running costs for heating in 1000s of homes of any system, achieving significant economies of scale over individual GSHPs and vastly improved energy efficiencies and longevity over air sourced heat pumps (ASHPs). Compared to an ASHP the average three-bedroom semi-detached house could expect to see savings of £115 per year and a three-bed terrace could save as much as £290.
Already widely used in new build and retrofitted in affordable housing towers, mansion blocks and houses, it can also serve terraced streets typical of British private homes. In a world first this year Kensa’s Heat the Streetsscheme in Stithiansin Cornwall connected an in-road retrofit networked GSHP to 98 homes. Residents can cheaply access a simple network that will provide cheap and clean ground heat for decades to come. Unlike traditional central plant high-heat networks, no heat is lost in the supply pipes, and you choose your own energy supplier and heat pump, paying a small standing charge to connect to the network. It really is like gas.
Unfortunately, current policy is not supporting these benefits. It supports ad-hoc installs of heat pumps which fails to get economies of scale or the simplicity of a street-based utility. Gas succeeded because once in your street, it was a no-brainer to connect to it as it was cheap and reliable. Put the ground sourced ‘heat main’ in your street and you get the same. After a period to allow the natural cycle of boiler replacements, gas can be turned off. Disruptive? No, the boreholes can be put in the street instead of the regular 10–15-year cycle of gas mains work and then lasts over 100 years – less disruption.
But the biggest savings are to UK plc. Leading consultants Element Energy have just published a report concluding this is the cheapest way for the UK to decarbonise homes. The higher efficiency of GSHPs, (which can also utilise off peak electricity to store heat for when it is needed) means that if just 40% of homes have GSHPs rather than ASHPs, by 2050, peak demand could be reduced by 28GW - equivalent to all of the UK’s 11,000 wind turbines. The reduction in energy demand would also save up to £10 billion a year in reduced grid infrastructure costs.
And Octopus and L&G have just announced the biggest ever investment in heat pumps to do precisely this.
In the 20th Century we switched from coal to gas because it was made easy and cost effective by connecting to the infrastructure that was put into the majority of streets. Networked GSHPs are simply the 21st-century equivalent.
Lord Matthew Taylor is a Liberal Democrat member of the House of Lords and former MP for Truro and St Austell.
