Decarbonising the heat needed in the tightly packed streets of Biddulph, Cheadle and Leek is a wicked problem, so far without a cost-effective solution. Hydrogen for homes has gone firmly out of fashion, despite new gas boilers being ready to take a blended mix. Air source heat pumps just don’t seem to fit in terraces that face directly onto the street and often have small courtyards out back.
But there are signs that another alternative may be on its way. Late last year, the Department for Energy Security and Net Zero (DESNZ) released a consultation on Heat Network Zoning, where suitable areas of domestic and commercial buildings are grouped together to take low carbon heat from a central source. Community Energy England and partners are looking to push out a model being developed in Rossendale, Lancashire, called Net Zero Terrace Streets. This model covers some of the same territory as heat zoning but is community-centred.
Intriguingly, the map released by DESNZ in its 110-page consultation includes at least part of Leek (and Buxton) but not Cheadle or Biddulph. It’s not obvious why this is so; the principal determinant of whether an area is likely to be suitable for heat zoning is heat density, crudely the concentration of demand for heating and hot water in any particular geographical segment, and the towns have similar heat profiles. Unsurprisingly, large cities, towns and aggregations of ex-mill or mining settlements figure prominently on the map. The Potteries, for example, is a hot spot of potential targets.
The government proposes to set up a central authority (DESNZ) and a series of local zone co-ordinators, which will be teams within or linked to local authorities. Once these local teams have reviewed the data and the boundaries, they will be able to award the right to develop a heat network within that area. In certain circumstances they will be able to require large users, typically commercial or industrial, to connect to a heat network.
Heat networks are well established in other countries – in Denmark, for example, over 60% of homes are plugged into this source. There are existing examples in the UK: the Leeds City Pipes project, the village of Swaffham Prior in Cambridgeshire or the Bunhill Row project in Islington, where homes are heated by recycled warm air from the Tube network. Typically, these have been associated with concentrations of local authority housing stock and only 3% of UK heat is currently provided this way. DESNZ estimates that 20% of UK heat could come from networks by 2050.
But even if the government initiative does become concrete, and removes some of the regulatory and planning uncertainties, it is not immediately clear where the sponsors for these networks will come from. One solution might be community groups, such as at Swaffham Prior. (Separately, DESNZ has also launched a consultation aimed at generally easing the way for the community energy projects to contribute to UK generation.)
One intriguing project is Rossendale Net Zero Terrace Street, a fully developed concept to use ground source bore holes placed in alleyways and highways to circulate heat via brine in an ambient loop. Each home will have a small heat pump to boost the heat that arrives in their home. A thermal battery or smart water cylinder (remember the ‘dumb’ ones?) will provide hot water.
The selected cluster of houses is at the edge of Bacup, an ex-mill town in East Lancashire. The housing tenure is a mixture of owner-occupied and privately rented; the houses are stone-built, and some are in a conservation area. The project would involve some element of retrofit, but with a pricing model that is built into the future tariffs, and would require no up-front outlay from either owners or landlords.
The barriers to such a project are considerable - how to get sufficient take up to make it viable, for example. Nevertheless, the Rossendale Net Zero Terrace Street concept is the most imaginative and fully-worked-through approach that we have yet seen to a seemingly intractable problem, and one that we certainly have in the Moorlands.