If the UK is going to achieve its target of reaching net zero carbon emissions by 2050, it will have to decarbonise the heat network. In layman’s terms, that means all our gas boilers – and there are more than 20 million of them – will have to be either converted to ‘green’ gas, or ditched altogether and replaced with an electric heating solution that’s powered by renewables.
There are already heat replacements on the market. Air source heat pumps – which extract heat from the air and pump it into radiators – are one already popular alternative to the gas boiler. Another is the biomass boiler, if you have the space to store the fuel. Then there’s the electric combi-boiler. This works just like a gas combi, but it uses electricity to heat the water that goes to your radiators. If you have solar panels this could be a great option, but if you’re just using electricity from the grid it’s expensive and (unless the electricity you buy is green) it’s likely to come from carbon intensive gas.
Another way to decarbonise heat is to use district heating networks, especially in new build estates. In the Nordic countries this has been used for years, running off geothermal heat. That can be an option for us in some areas of the UK too.
Another option is to power our gas boilers with hydrogen – but there’s a catch. Currently, hydrogen is created through a complex process that’s driven by methane, which is a very potent greenhouse gas. So, hydron that’s produced by this method isn’t carbon neutral. But you can make hydrogen without carbon intensive inputs (and outputs). That’s by using renewable electricity from wind turbines or solar panels to electrolyse water. This ‘green’ form of hydrogen has traditionally been expensive, but the costs are coming down as renewable wind and solar technologies become cheaper.
The Government has recently announced a Green Homes grant to help home owners reduce their carbon impact. The grants – of up to £5,000 or £10,000 for people on low incomes – cover energy efficiency measures such as loft insulation, air source heat pumps, biomass boilers, replacement windows and doors, and heating controls.
One notable omission to the green grants is replacement natural gas boilers. This signals intent from the government that it won’t support heating our homes using carbon intensive fuel. There’s growing support for all boilers installed from 2025 to be hydrogen-ready, and some companies are already making them.
The natural gas industry is keen to position hydrogen as the best opportunity to decarbonise our heat networks – by blending ‘green’ hydrogen with current gas flows and eventually upping the amount of hydrogen in the mix.
It’s certainly an important ingredient in decarbonising, but it shouldn’t be the only focus for research, development and investment. Heat driven by locally generated energy (heat pumps powered by renewables), and by district heating (again powered by renewables) are the other two equally important ingredients in providing low-cost heat to our homes that doesn’t cost the earth.
For more information on the Green Homes grants visit https://www.gov.uk/guidance/apply-for-the-green-homes-grant-scheme – but hurry, because it closes in March!