Energy supply

We want London to have secure, affordable and low carbon energy. That means using less energy in our buildings, and generating more of our energy locally. Our energy activities are also helping us to meet the Mayor’s climate change targets.

Energy supply

​​​Generating energy locally is more efficient and helps to cut London’s carbon emissions. That’s why the Mayor has set a target to supply 15 per cent of London’s energy from renewable, local sources by 2030.

At the moment, most of London’s heat and hot water needs are supplied by the gas grid with boilers in each building. London’s electricity comes from the electricity grid. Power in this grid is generated in large powers stations outside of London. The heat produced when generating electricity in power stations is not used, but just goes up the chimney into the atmosphere.

Local energy, also known as decentralised energy, is any heat or electricity that is generated and supplied in London. This includes solar panels, and local heating networks supplied by plants which are close to where energy is used and are highly efficient in generating heat and power at the same time (combined heat and power). This means they use less energy than conventional energy systems in meeting the same energy demand.

We’re helping to generate energy locally through our energy supply programmes.

The London Energy Plan

The London Energy Plan has been developed based on recommendations from the London Infrastructure Plan. The initial outputs of the London Energy Plan are a spatial map of London’s energy supply and demand to 2050 and options for the required supporting infrastructure. It includes projections of heat and electricity infrastructure, retrofitting of the built environment to reduce demand, and electrically-powered transport.

For more information on the London Energy Plan and to explore the interactive map see our scenarios to 2050 page.

Decentralised Energy Project Delivery Unit (DEPDU)

DEPDU supports London boroughs and other private and public sector partners to develop decentralised energy projects, some of which include heat networks. It gives technical, financial and commercial advisory help for larger energy projects. Most of these are projects get their heat either when energy is generated from combined heat and power (CHP) energy generation, or from sources of waste heat that are not being used. Waste heat includes heat from the London Underground, data centres and industrial processes.

DEPDU was set up with €3.3m funding, 90 percent of which was from the European Investment Bank’s ELENA fund, and will offer specialist advice until March 2016. We have already supported London boroughs and partners to take 13 decentralised projects to market. These are worth a total investment of over £100 million. We’re also supporting another 8 projects, with a total investment potential of over £150 million.

To help heat networks interconnect and operate efficiently and effectively, we have also produced guidance. The London Heat Network Manual gives technical and other advice on developing heat networks for developers, network designers and energy producers.

Decentralised Energy Enabling Project (DEEP)

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DEEP, the successor project to DEPDU (Decentralised Energy Project Delivery Unit), has been established to provide public sector intervention and support to larger-scale decentralised energy (DE) projects in London that the market is failing to develop and realise. DEEP procures strategic, technical, commercial/financial and legal advisory support services through an OJEU framework to help beneficiaries bring larger-scale DE schemes into operation in order to significantly reduce CO2 emissions at market-competitive prices and increase renewable energy generation capacity in London.

The £3.5m-project is 50% funded by the European Regional Development Fund (ERDF). The framework is commenced on 26 June 2017 and the contract award is published. 

Beneficiaries can call off services from the framework which – subject to GLA agreement – will be funded by the project. The project will fund all work [not capital] related to DE projects from early stage heat mapping/energy master planning, taking project ideas from concept through to feasibility, business case, procurement and commercialisation.

A procurement briefing document has been provided describing how to procure a supplier from a sub-lot of the framework.

Prospective beneficiaries interested in receiving services from the project should sign a Support Agreement (SA). From signing a SA and agreeing a scope of works with the GLA that aligns with Mayoral priorities – as well as beneficiary priorities – a specification will be jointly written between the DEEP project and beneficiary.

Read the Framework Agreement.

Please note that all public bodies within England & Wales can make use of the framework for their own procurement activities. Any organisation commissioning works from the framework not funded by DEEP should notify the GLA at the email address provided below.  

A stakeholder event was held on the morning of Tuesday, 24 July 2018 at City Hall. View presentations from the event

To date (August 2018) DEEP has commissioned 11 pieces of work with a number of other organisations outside London utilising the framework for their own DE procurement undertakings. We expect to commission more pieces of work throughout 2018 and into 2019.  

Information updates on the project are made here periodically.

If you have any questions about the project, please send an email to [email protected].


We’re working with Islington Council and our project partners to support cities in the UK and across Europe with building more heat networks as part of the European-funded CELSIUS project. Islington Council, for example, is using waste heat from the London Underground to heat homes on their Bunhill heat network. For more information and to see an interactive video explaining the project visit the CELSIUS Cities website.

London Heat Map and energy masterplans

We’re working with London boroughs to identify where heat is used in the city and where market-competitive heat networks could be located. Areas with many buildings close to each other that need a lot of heat are often best suited for heat networks. We’ve supported all the London boroughs to develop heat maps and helped to create 12 energy masterplans for different areas of the city. We’ve published all these, and other energy supply and demand information, on the London Heat Map to help developers, London boroughs and others to create and locate new heat networks.

As part of our approach to decarbonising London’s heat supply, it is important to understand how much of our existing building stock could be connected to new and/or existing heat networks, where those are and what the technical challenges and financial costs would be for doing so. This will feed in to our energy masterplanning work and inform our strategic approach to decarbonising London’s buildings through a combination of reducing energy demand and decarbonising energy supply. The GLA received funding from the Carbon Neutral Cities Alliance (CNCA) to undertake a research project called ‘Accelerating the Transition to 4th Generation District Heating Systems’ to look at this and a link can be found to the final reports at the bottom of the page under the ‘Energy Supply Studies’.

Licence Lite

We’ve become the first authority in the country to go operational with a new type of electricity licence. Licence Lite lets smaller, local electricity suppliers sell power to the market without the significant licensing requirements and costs that larger suppliers need to meet.

Having the new licence will mean we can buy excess electricity generated by London boroughs, public bodies and others and sell it to consumers, offering better prices to the generators. To start off with we’re looking to sell it to Transport for London and may expand this to others like the Metropolitan Police, the NHS and the private sector.

We successfully concluded our contract negotiations with the generators, TfL as the consumer and nPower as the Third Party Licence Supplier. On 20 December 2017 Ofgem formally announced that our application for Electricity Supply Licence Lite was successful and that the licence was granted. The project started operation on 1 January 2018.

Energy supply studies

We publish information and data on energy supply in London to help developers, London boroughs and businesses supply more local energy:


Communal Heating Consumer Survey Report - this survey was commissioned in 2017 to establish the views of consumers in London connected to communal and district heating networks that provide their space heating and hot water requirements.  The survey report was published in October 2018.  A total of 384 surveys were carried out across 44 sites. The results and conclusions were similar to those of other reports and the BEIS Heat Network Consumer Survey (2017): the majority of heat customers served by communal and district heating networks were satisfied with their heating arrangements.‎

The London Heat Network Manual - this study provides practical guidance to local authorities, energy services companies, developers and planners on the development and delivery of heat networks in London. It includes chapters on designs, standards, construction, management and innovation of district heating. A revised and updated version of this manual will be completed by the end of 2018


The Decentralised Energy Capacity Study- this study has data and analysis of the potential for renewable energy and heat networks in London.

Secondary Heat Study – London’s Zero Carbon Energy Resource - this report looks into waste heat sources that could supply local energy to heat networks in the future.

Powering Ahead: Delivering low carbon energy for London - this report explains the commercial, regulation and policy requirements needed to develop of heat and power networks in London.

Smart Energy - Intelligent Management of London's Energy Supply - this study looks at how new ‘smart’ technologies can help to cut the amount of peak energy London uses.

Energy Masterplans – this reports identify decentralised energy opportunities in some of the London Boroughs and are available to download on our London Heat Map website.

Connecting existing buildings to district heating networks – this report looks at the technical challenges and financial costs of retrofitting existing buildings’ heating systems so that they can be connected to district heating networks, as well as some of the challenges of maintaining thermal comfort in buildings whilst reducing the supply temperature of heat networks. Read the summary report and the technical report.

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