To facilitate achievement of its goal of having 25% of energy supplied by decentralized sources by 2025, the Greater London Authority developed the Decentralised Energy Master Planning (DEMaP) district energy programme, which ran from 2008-2010, with funding of €3.3 million (US$3.7 million). It focused on identifying opportunities for district heating networks through heat mapping and energy masterplanning as well as building capacity within local authorities to deliver district energy projects and develop planning policies that encourage, and where appropriate require, district energy in new developments. The main output of the programme was the London Heat Mapxxxii, which showcases potential heat supply, demand and network opportunities for district energy across the city.


The London Heat Map is an interactive GIS tool that allows users to identify opportunities for decentralised energy projects in London. The Heat Map provides spatial intelligence on factors relevant to the identification and development of district energy opportunities, such as: location of major energy consumers, local and city-wide fuel consumption and CO2 emissions, energy supply plants, community heating networks, and heat density. It is publicly accessible to anyone with an interest in district energy. Local authorities can use the map as a starting point to developing detailed Energy Master Plans to inform district energy policies in their Local Development Frameworks and climate change strategies. Developers can use the map to monitor compliance with the London Plan district energy policies (connection into an existing network or extending their own communal heating networks beyond their site boundaries). In addition, the periodically revised ‘London Heat Network Manual’xxxiii provides practical guidance for local authorities, energy service companies, developers, network designers and planners on the development and delivery of heat networks in London.

Based on opportunities identified through the London Heat Map, London is already developing a number of district heating projects, such as the Lee Valley Heat Network, which aims to provide over 5,000 homes with required heating and hot water through harnessing waste heat sourced from a nearby EcoPark. On the city-level, London has continued with the Decentralised Energy for London programme, providing assistance for commercialisation of large decentralised energy projects, primarily looking at district heating schemes supplied from CHP and waste heat.

Reasons for success

The success of London’s energy mapping approach is based on the city’s rich planning and monitoring experience, as well as availability of multiple communication platforms that facilitate reporting from building owners and public disclosure.

When/why a city might apply an approach like this

Comprehensive energy mapping, although often cost and planning intensive, is a crucial stepping-stone for city-wide development of district energy systems. It provides a critical overview of demand and supply to help guide district energy network prioritisation and maximise renewable energy – like waste heat and free cooling – sources. For cities that have recently started district energy planning, energy mapping provides multiple benefits, from comprehensive information to establishment of initial relationships with building owners during information gathering, which might facilitate later development of district systems. Cities that are hoping to support other local and regional authorities to pursue district energy systems will find energy mapping to be an important enabling tool. 

C40 Good Practice Guides

C40's Good Practice Guides offer mayors and urban policymakers roadmaps for tackling climate change, reducing climate risk and encouraging sustainable urban development. With 100 case studies taken from cities of every size, geography and stage of development around the world, the Good Practice Guides provide tangible examples of climate solutions that other cities can learn from. 

The District Energy Good Practice Guide is available for download here.  The full collection of C40 Good Practice Guides is available for download here.  

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  • Economic
Key Impact
Support to reach 25% of energy supplied by decentralized sources by 2025
Financial Savings
US$3.7 million
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