Decarbonising heat: 9 things you need to know

The debate on decarbonising the UK housing stock has intensified this week. With the scale of the challenge looking as daunting as ever, consumer groups say more support is urgently needed. Here is what you need to know.

The electrification of household heating will also require upgrades to energy efficiency. Photograph: Getty Images The electrification of household heating will also require upgrades to energy efficiency. Photograph: Getty Images

Heating homes ‘generates more emissions than driving cars’

The scale of the heating decarbonisation challenge is huge. According to figures released by the National Housing Federation (NHF) this week, England’s 25 million homes – which produce 58.5m tonnes of CO2 every year – emit the equivalent of the average annual use of 28 million cars. There are 27 million million cars in use in England, emitting 56m tonnes of CO2 annually.

‘Leaky’ housing stock drives emissions 

The NHF says the emissions from homes are so high due to a combination of gas central heating and poor insulation, meaning heat easily leaks out of homes which then require even more gas to keep them warm enough.

There is a lack of awareness on the issue 

Many people are unaware of the issue or unable to make their homes greener. A 2020 Ofgem survey found that three in every five (60%) homeowners do not think their home energy use has much of an impact on carbon emissions. A survey last month by NatWest banking group and IHS Markit also found that one in four homeowners (28%) have no plans to make “eco-upgrades” to their homes in the next ten years.

Leading to calls for the government retrofit social housing

The NHF is calling on the government to put £3.8bn into the retrofit of social housing in the upcoming spending review. Social housing landlords often own thousands of homes, can make them energy efficient at scale and have the necessary systems set up and ready to act. Unlike private landlords and homeowners they can retrofit whole streets, estates and even neighborhoods simultaneously, says the NHF.

There are also calls to make clearer information on retrofitting available

A coalition of consumer and industry groups worte to the prime minister Boris Johnson this week calling for accessible, unbiased guidance on the changes needed for their homes and how to make them. 

They said many people have difficulty understanding what home technologies to install. There is too little information about the different options available and the benefits they’re intended to deliver.

To increase uptake, consumers need financial protection

The coalition, which includes Citizens Advice, the Federation of Master Builders, the Aldersgate Group and Which? says currently, inadequate protections mean when installers go bust, people find it difficult to fix problems and are left with guarantees and warranties that are “useless or difficult to enforce”. Furthermore, “if protections for the net-zero transition don’t keep up with the pace of change, we open the door to scammers and rogue traders,” it said.

Financial support is key 

According to the letter, the vast majority of people will be unable to make these changes without financial support like grants, low-cost loans and financing. The letter calls on the government to bring forward specific support schemes for people who are fuel-poor, in vulnerable circumstances or less able to afford these changes. 

Decarbonising homes is currently too complicated

The coalition says right now the process of installing low carbon heating, upgrading insulation or installing smart technologies is “time-consuming, confusing and stressful”. “Researching and choosing the right technology, finding a reputable installer and having the work completed demands huge amounts of knowledge, time and effort,” the coalition said.

There are a number of options for decarbonising heat: 

Electrification

Electric heating technologies, such as heat pumps are available to buy now. As power sector emissions fall, emissions associated with electric heating are decreasing rapidly - in theory. However, the Energy and Climate Intelligence Unit (ECIU) points out that because the costs of electricity are currently higher than for gas, electrification could be an expensive option. The use of technologies such as heat pumps will also require upgrades to energy efficiency  such as the fitting of insulation.

Hydrogen boilers 

The natural gas that most homes use for heating could be replaced with hydrogen, which releases energy but not carbon dioxide, the only waste product is water. However, for hydrogen to work, the pipes in the national gas grid would need to be replaced and home boilers would need to be adapted or changed, which could incur considerable costs. There are also a number of ways in which the hydrogen is produced, some of which create carbon emissions.The benefit to this technology is that it requires very little behavioural change on the part of the homeowner.

Biomethane boilers

Biomethane, which ​​produces less carbon than natural gas over a full lifecycle, is chemically identical to methane from natural gas, so is suited to existing infrastructure and appliances. It is unlikely, however, that it can be produced in sufficient quantities to replace fossil gas entirely, according to the ECIU.

Hybrid systems

A hybrid system combining both electrification and hydrogen is a third option. Here, heat pumps could be used to meet the majority of heat demand, with a (low carbon) gas boiler taking over in extremely cold weather. The ECIU says advantages of this approach include helping establish a market for heat pumps while hydrogen is developed to displace natural gas in the hybrid system eventually, and the ability to call on hydrogen when heat demand is at its very highest.

Heat networks

Heat networks connect a central heat source to a number of buildings via a series of underground hot water pipes, and are popular in Scandinavian countries. The government expects the heat networks market in the UK to grow quickly to supply up to 20% of heat demand over the next decade or so and has invested £320m into its flagship Heat Networks Investment Project to help get this underway.

Heat networks work particularly well in built-up urban areas or industrial clusters where there is a large and concentrated demand for heat.

Biomass

Biomass can be used to reduce emissions when used instead of more polluting fuels like oil in off gas grid properties. Support for biomass boilers has been available since 2011 via the Renewable Heat Incentive (RHI), but take-up has been low.

The Committee on Climate Change says rather than burning solid material such as wood, this resource may be better used in other sectors of the economy such as construction, where it provides carbon storage without the need for CCS and reduces demand for carbon-intensive materials such as steel and cement.

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