How can the GLA support heat network zones to reduce London’s carbon emissions?

The London Assembly Environment Committee is investigating the implementation of heat network zoning pilot areas and consider the implications for future delivery across London in support of reducing London’s carbon emissions.

Heat Networks use shared sources of heat to improve the energy efficiency of heating systems. While old district heating systems use fossil fuels to generate energy, the most efficient, low-carbon networks use ambient heat (heat stored in the air or water), or waste heat (such as from the London Underground, energy-from-waste plants, or data centres).

This investigation will examine the lessons learned from the implementation of heat network zoning pilot areas and consider the implications for future delivery across London in support of reducing London’s carbon emissions. It will seek to:

• Understand the practical experiences of constructing and connecting new heat network zones in London;
• Gather insights on the potential savings associated with the expansion of heat networks, with particular regard to both carbon emissions and long-term energy costs; 
• Explore the experiences of people living in buildings connected to heat networks in London;
• Investigate what is needed to connect sources of ambient or waste heat – such as the London Underground or data centres – to heat networks;
• Assess how the GLA’s approach is supporting this work, including updates to the London Plan.

• The Mayor’s pathway to reduce London’s carbon emissions is based on 460,000 new heat network connections by 2030. It states that to achieve this, heat network zoning will be required to designate zones with tailored policy to support delivery, including mandates for existing and new domestic and non-domestic buildings to connect.
• Heating homes contributes to around 18 per cent of the UK’s climate emissions. Currently, over 477,000 households – representing more than 1.1 million people in the UK - are connected to a heat network. Around 30% of these are in London. In February, the government stated that it expects “about 20% of the UK’s heat demand will be met by heat networks by 2050, which will be a significant increase from the current figure, which is about 3%”.
• The London Boroughs of Barking & Dagenham and Southwark were part of the government’s heat network zoning pilot. Old Oak Common (OPDC) is one of the first six designated heat network zones in England, announced in October 2024. OPDC’s new heat network is expected to deliver 95GWh of heat across five phases between 2026 and 2040. The project was awarded £36m from the government’s Green Energy Heat Network Fund in November 2023.
• In autumn 2025, the government is expected to set out that specific buildings within zones will be required to connect to a heat network within a prescribed timeframe.

• What value are new network connections providing in London and how realistic is the target of reaching 460,000 new heat network connections in London by 2030?
• What are Londoners’ experiences of new low-carbon heat networks? Are they providing cheaper and reliable heat?
• What is the process for connecting existing sources of ambient or waste heat to heat networks, and how can this process be simplified and accelerated?
• Is the GLA providing effective support and working with the key stakeholders in central and local government to accelerate the uptake of heat networks?
• What lessons can be drawn from the heat network zoning pilots to inform the new London Plan and wider rollout of heat networks in London, including how this is communicated?