District heating is a potential low carbon option for some homes, though it is hard to say at the moment which homes (if any) will have the opportunity. Compared to switching to a heat pump or getting an electric storage boiler, district heating can be a low hassle option - as villagers in Swaffham Prior have discovered and it seems likely that residents of Grantchester will also get the opportunity too. Compared to air source heat pumps, community heating is quiet, less bulky and you don’t need space for an outside unit; also it is a lot less weighty than an electric storage boiler: a 40kWh Tepeo weighs 375kg. A community heating system means digging in the street and into your home for the pipework. Apart from that you swap your boiler for a heat interface unit that provides you with heat and meters your consumption. Depending on the setup, you may also need hot water storage. There is no need for an annual service, as you should have with a gas boiler.
A shared heating network is often the best solution for people who live in apartment blocks, though it is sometimes possible to fit air source heat pumps with just a duct to the outside.
Cambridge City Council is working on a low carbon heat network now. It is currently designed around public buildings and university buildings as ‘anchor’ loads but could be extended into residential areas in time. Digging up the roads to put heat networks in is expensive and it is much easier to get finance if you have contracts to supply a large amount of heat before you start. It is also important to have a high density of heat demand so there is not too much pipe work per customer and that can be difficult to arrange for a residential area with lots of other viable heating option since you do not know how many people will connect. However, if you take your gas boiler off the table - because it is not compatible with net zero carbon - a district heating solution can look attractive.
Shared heating systems are very common in Scandinavia, Germany and Austria. They have a bad reputation in this country but things are improving. Since 2014, all new heat networks (and some older ones) are required to meter consumption and bill accordingly. You are in control of the heat you use and are charged for. Also OFGEM will soon have powers to intervene on pricing. A survey of heat network customers (both community heating in single buildings and larger heat networks) found that more shared heating customers were satisfied with their heating systems than people with individual heating systems (74% compared to 67%). They were also less likely to have experienced discomfort due to cold than people with individual heating systems (33% compared to 42%). Problems do occur, with half of customers saying that they had experienced a failure of some kind over the previous year, but this rarely lasted more than a day.
District heating takes years of planning and has high capital costs so it is hard to get a project going and probably impossible without council support. However, Nick Gay, vice chair of the County Council Environment and Green Investment Committee, told the Energy Group this year that the council would look favourably on any scheme with good local support. The Energy group has discussed district heating a few times over the years, most recently in September this year (slides here).
More information and links
Swaffham Prior Heat Network now has more than 100 active customers and more waiting for connections. They use renewable heat from a combination of ground source and air source heat pumps and they also have a contract for renewable electricity from solar panels. They celebrated the anniversary of their first customer connection on 13th October this year.
Grantchester heat network is at a much earlier stage. The feasibility study, completed in 2022, is favourable and they are looking to use renewable heat from the River Cam as well as air source heat pumps. This project is championed by parish councillor Josh Newman.
https://scene.community/case-studies/grantchester-heat-network
Legislation is changing to improve protection for customers of heat networks. OFGEM will have powers to intervene in the case of unreasonably high prices on heat networks. Heat networks need energy to generate heat but they do not count as domestic customers so they can face higher energy prices. The government is considering extending the price cap to cover heat network providers.
The rules for metering of heat networks
https://www.gov.uk/guidance/heat-networks
The survey of heat network customers
Here is a nice explanation of how community heating schemes can happen - from Nesta. https://www.nesta.org.uk/data-visualisation-and-interactive/switching-streets-to-low-carbon-heat/
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