A district heating scheme comprises a network of insulated pipes used to deliver heat, in the form of hot water or steam, from the point of generation (usually an energy centre) to the end user.
Networks vary in size and length, carrying heat just a few hundred metres between homes and flats, to several kilometres supplying entire communities and industrial areas. The distance a network can reach is also easily extended by simply adding more providers of heat, or ‘heat sources’, along the way.
A heat network enables valuable energy, which is all too often wasted in power generation or industrial processes, to be captured and supplied to householders and businesses. This removes the need for additional energy to be generated. It also allows for economies of scale, as the generation of heat in one large plant can often be more efficient than production in multiple smaller ones.
Heat networks can be supplied by a diverse range of sources including:
- power stations
- energy from waste (EfW) facilities
- industrial processes
- biomass and biogas fuelled boilers and CHP plants
- gas-fired CHP units
- fuel cells
- heat pumps
- geothermal sources
- electric boilers and even solar thermal arrays
The ability to integrate diverse energy sources means customers are not dependent upon a single source of supply. This helps guarantee reliability, continuity of service and can introduce an element of competition into the supply chain. It also allows for decarbonisation of the heat source in the long term.
Networks also have the ability to balance the supply and generation of heat, across location and over time. Over the course of the day, heat demand shifts between residential consumers to commercial, industrial and public buildings and back again. A heat network can match and manage these flows, whilst maximising the utilisation of the plant providing the heat. Demand can also be managed across seasons, with networks supporting the operation of distributed absorption cooling plants in the summer providing cooling on a significant scale.
Heat Networks in the UK
There are over 17,000 heat networks in the UK of which around 91% are located in England and 6% in Scotland. There are nearly 492,000 connections in total including 446,517 domestic customers, 33,273 commercial customers, 4,670 retail customers, 320 light industrial customers, 1,456 universities and school and a further 4,865 mixed use networks.