Heat networks and climate change

In the UK approximately 40% of our energy consumption and 20% of our greenhouse gas emissions are due to the heating and hot water supply for our buildings.

Infographic from the CCC's Next Steps for UK Heat Policy Report, see below.

The UK government has legislated that we must recude greenhouse gas emissions to net zero by 2050. This provides the legal imperative to decarbonise the heat sector, which means that the UK will need to eliminate almost all emissions currently produced by heating and hot water consumption.

Heat networks are a part of our pathway to decarbonising heat, through efficiency of supply and the fuel source.

Economies of scale

It can be more economic to have one large heat generator and pipe the heat to many properties, than for each property to have its own generator, especially where there is a large capital cost associated with the heat generator (eg ground arrays for heat pumps). They are most efficient in heat dense areas, where pipes can be shorter between properties.

Fuel source

Heat networks are fuel agnostic, and so can be heated by any fuel. This includes low carbon heat generation from the beginning, or switch to an alternative source of heating at a later stage. See here for some examples of renewable sources of heat for heat networks in the UK already, from otherwise wasted heat to geothermal.

Additionally, thermal stores are increasingly used to balance demand swings and maintain supply during short outages. These are typically large insulated tanks of water that can store excess heat from generation at periods of low demand and supply heat at periods of high demand.

History

Heat networks have been widely used in Denmark since the 1970s, and are an established technology. However in the UK heat networks only supply 2% of current heat demand, having developed the gas grid to fuel boilers in individual dwellings as the main heating source since the 1970s. Please see our timeline of how the history of heating in the UK has developed.

Even so, around 13% of households in the UK are still not connected to the gas grid, where heating is supplied largely by oil heaters and sometimes electricity, or heat networks.

Future of heat networks

Scientific recommendations

The Committee on Climate Change (CCC) is the independent advisory body to the UK government on targets and progress made in reducing greenhouse gas emissions and preparing for climate change. The Committee identified what it calls low-regret routes to reducing emissions from heating buildings that the Government should pursue immediately which included “the roll-out of low-carbon heat networks in population-dense urban areas, along with energy efficiency and other measures”.

In its latest advice to the UK Government on the UK’s ‘carbon budgets’, the Committee recommended growth in heat networks, with up to 18% of heat demand met by heat networks by 2050 (see table below) from a current baseline of about 2%.

Their recommendations also included a major programme to build and extend low-carbon heat networks in heat-dense areas, connecting 1.5 million homes by 2030 and reaching 5 million homes by 2050.

This encompasses both retrofitting existing homes (there are about 29 million homes currently in the UK) as well as connecting new homes. This comes in conjunction with advice that after 2025, no new homes should be connected to the gas grid, and that new homes should have low-carbon heating systems instead.

The CCC also emphasised the expansion of non-domestic connections to heat networks, which in their ‘central’ scenario would account for 53% of total heat delivered by heat networks by 2050 (although only 28% of UK heat demand is non-domestic). Non-domestic buildings are largely concentrated in urban areas with a higher heat density, where heat networks are more likely to be deployed.

Government support

As part of their commitments to reducing their carbon emissions, the UK and Scottish governments are supporting the development of heat networks, through investment incentives and developing regulation which will support the sector.

The UK government department for Business, Energy and Industrial Strategy (BEIS) set out the context of the government’s support for heat networks and the role of the sector in the decarbonisation of heat in a report in December 2018. This responded to the CMA’s market study and the ADE’s Shared Warmth report on the heat network market.

Government acknowledged in the Clean Growth Strategy that they have set out a significant role for heat networks as a ‘low regregts’ component of meeting their decarbonisation commitments. They recognised that for the last 50 years we have largely relied on gas to heat our buildings, and heat networks are a key technology which can facilitate the transition away from fossil fuels towards low carbon energy sources.

See https://www.gov.uk/guidance/heat-networks-overview or our existing legislation section for more information on how the UK and Scottish governments are supporting heat networks. Also see our reports section for further reading on the development of the heat network market in the UK.