Almost 50% of UK electricity now comes from renewable sources, and green energy has moved from niche to normal. However, almost 90% of our domestic energy usage is still carbon-emitting. That’s because gas remains the dominant source of home heating. Next year, that will start to change, thanks to a wider adoption of electric heat pumps, which are three times more energy-efficient than using gas, and can draw their power from clean sources.
Heat pumps take heat from outside a building and deliver it inside (like air conditioners in reverse). Their energy efficiency comes from the fact that they use power to move heat rather than to generate it. Even when outside temperatures are well below 0°C, there is plenty of heat – remember that absolute zero is -273°C – so there’s a lot of energy to be extracted. That is why heat pumps work well in all climates.
Heat pumps are common in some countries, but, in most, natural gas dominates due to price. Purchasing and installing an air-source heat pump currently costs just under £10,000 – a huge barrier for consumers when their fossil-fuel-gobbling rivals cost less than £3,500. One reason for this is that heat pumps are currently a bespoke option, with units customised to each location. This denies the sector economies of scale, while putting off potential adopters of the technology.
Next year, that will change, as heat-pump manufacturers turn their attention to capturing the mass market – bringing costs down by standardising hardware and training more engineers. In 2022, this will almost halve the cost of heat-pump retrofits to around £5,500 per household. Technological innovations will drive improvements, enabling heat pumps to work in most homes.
In many countries, heating infrastructures have been designed and built around a system of artificially cheap natural gas. In the UK, for example, gas typically costs around 3p/kWh whereas electricity costs around 15p/kWh. This difference is explained in no small part by tax policies. About 23% of a UK electricity bill is green taxes, compared to only two per cent of a gas bill. These high taxes on electricity are common across Europe as governments have used them to subsidise renewable-electricity generation. However, this has led to the perverse situation where electricity is now increasingly clean, but heavily taxed.
Changes in energy-tax policies will make green electricity cheaper than natural gas. With increased competition in the heating sector – bringing hardware and installation costs down – 2022 will see electric heating go mainstream.
Some commentators argue that countries’ electricity grids will not be able to cope with that extra demand, but the opposite is true. Heat pumps are a good way of using electricity more efficiently by using spare capacity and shifting load. We will be able to balance them with, for example, the charging of electric cars. On winter evenings, pumps could be used to discharge some battery power back into the house, reducing heating costs at peak times and making the whole system more efficient. And, as heat pumps can often run in reverse, they can act as a cooling system in summer.
In 2022, on the cusp of a green-heating revolution, we will wonder why we used such carbon-intensive fuels to heat our homes.
The article originally published on Wired.