Arup's Malcolm Ball argues that plotting the potential for low-carbon heat demands a joined-up approach
Heating homes, businesses and public buildings accounts for 17 per cent of end-use CO2 emissions in the UK. So meeting the government's targets to reduce emissions by 80 per cent by 2050 will rely on developing commercially viable district heating networks.
Generating low-carbon heat isn't difficult, but distributing it is. You need to develop district heating networks, but first you need to identify where it's commercially viable to install them.
The solution? Heat maps. By plotting supply and demand, heat maps show where combined heat and power (CHP) and district heating schemes are viable. Once the heat map has identified opportunities, more detailed technical and financial feasibility studies can be carried out.
As part of our work on the city's Decentralised Energy Master Planning (DEMaP) programme, we manage the London Heat Map that is currently being updated with real-world data collected by the different boroughs. In London, having a common map helped join everything together across boundaries. So a large heat demand in one borough could be linked easily to a source in a neighbouring area.
The map has already helped to develop smaller projects in London, with a flagship scheme targeted to connect up to 120,000 homes, businesses and public buildings through 67km of pipework. It will reduce annual CO2 emissions by 100,000 tonnes.
With several schemes now close to completion, and suppliers, funders and customers negotiating contracts, London will soon have more community energy projects. Together they will help the mayor of London meet his targets to reduce carbon emissions by 60 per cent and decarbonise 25 per cent of the city's energy supply by 2025.
Indeed, the mayor's environment advisor, Martin Powell, believes the London Heat Map is providing boroughs, private sector developers and heat suppliers with a reliable source of information about where distributed energy networks and opportunities exist. His view is that this is an essential part of a suite of interventions being made to encourage and enable the delivery of district heating networks in the capital.
One key to London Heat Map's success is its use of building specific real-world data. Many other heat maps, including the national maps developed so far, use benchmarked data rather than actual readings.
The team behind the map also took the kind of pragmatic approach that building a national heat map would demand. Our energy strategy team has made it clear there is a need to carry out detailed mapping on places that had obvious opportunities. For example, we have identified some outer boroughs where we know there are fewer opportunities for district heating.
It's an approach recommended on a national level: there's little value in heat mapping the Outer Hebrides when they can't support a heat network. Indeed, a national map would need to look at which sources of low-carbon energy are right for each area. So, for example, southwest UK has more biomass available and also has the potential for tidal or wave energy. In urban areas, district heating is the obvious solution.
There's a strong argument for UK policy to follow London's lead. The London Plan – the spatial plan for the capital – says new developments must use the London Heat Map to see if they can connect to a heat network. In fact, the previous government's Household Energy Management Strategy recommended London's approach should be replicated nationally.
Ultimately, we need a national map, drawn up to common standards and open to everyone, to help identify the best opportunities for low-carbon heat across the country. And with the deadlines for reducing emissions drawing nearer, we need it now.
Malcolm Ball is head of the energy strategy team at Arup