Did you know that there are 23 million homes in the UK (some 83% of the total) that use natural gas (methane) for their central heating? Of course, gas is a fossil fuel so the immediate response is “That’s awful! We must stop using gas! We must convert everyone to electric heating!”
But it’s not that simple.
There’s a lot of talk about heat pumps and, on the face of it they sound great – extracting heat from the colder air outside (air source heat pumps) or from the ground (ground source heat pumps) and then, a bit like a refrigerator, pumping that heat into the house for their central heating and, possibly, to heat their hot water (though it’s also possible to have solar based systems on the roof to heat water directly).
Building all new houses so that they are perfectly insulated and installing heatpumps is a no-brainer. In my opinion it should be mandatory on all new-builds.
However, for the rest of the UK housing stock, there are major complications:
- Many houses cannot be insulated to the level needed to make heat pumps viable – they will always lose heat faster than a heatpump can provide it in the colder weather. Insultation in many cases will reduce heat loss by only 10%.
- While the cost of heatpumps is coming down, the actual pump isn’t the biggest part of the cost. A traditional gas-based heating system would have to be completely ripped out and all radiators replaced with either underfloor heating and/or new radiators three times the size. Heatpumps pump warm water around the house BUT it’s far cooler than a traditional gas heating system provides (often less than 30oC compared with above 60oC). To get enough heat out of the cooler water requires far more surface area – either your complete floor or massive radiators. This can cost £15000 to install, in addition to the pump itself, depending on the size of your house.
- Ground source heat pumps required a lot of ground, which is great is you have a large garden but not so if you live in a flat. For example if everyone in Southampton wanted to heat their homes using ground source heat pumps it would require an area of land equivalent to the whole of Hampshire!
- The UK’s power stations, solar farms and wind turbines etc can only generate a maximum 60 Gigawatts of electricity (60,000,000kW) and, on a cold day, we use pretty much all of that. If everyone swops from gas to electric heating then we will need far more electricity than we can generate – estimates vary but 100GW extra is a likely figure). That’s a lot of new power stations! Or colossal numbers of wind turbines (though I wouldn’t want to rely on wind power exclusively to heat my house as there’s often very little wind in the ‘high pressure’ periods that come with the very cold, bright weather in the winter).
- if we want to decarbonise our heating by 2050, then we have only about 15 million minutes (if we assume the installers work round the clock). A quick calculation shows that if the UK wants to convert every house to electric heating then we should be replacing gas heating systems at the equivalent rate of 1 house every 36 seconds starting NOW, for the next 28 years.
In my opinion this isn’t likely – we haven’t even managed to install smart meters into every home in the UK yet!
So what should we do?
I’d suggest that the UK has an exceptional opportunity to solve this problem in a way that very few other countries could. We should re-purpose our gas grid (underground gas pipes) to carry hydrogen to our boilers and burn hydrogen instead of methane! There’s no carbon dioxide from burning hydrogen!
The UK is very unusual in having miles of gas pipes under the ground (because we discovered North Sea gas!). Most European countries use electricity far more for heating as they don’t have access to their own gas supplies. (N.B. European countries’ reliance on Russian gas is more for generating electricity than for direct heating). So this is something we could do which most countries couldn’t.
If you’d like to know more about the opportunities that hydrogen offers for decarbonising the UK, listen to this podcast Transitioning heating to hydrogen w/ Professor Averil Macdonald OBE | The Climate Fix or look at the Thought Provoking Questions on Outreach link on this website, Thought provoking questions – Livery Climate Action Group (liverycag.org.uk).