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Last edited 19 Jan 2021

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What can government do about district heating

Imagine a country where few houses have mains electricity or gas connections or pre-purified water supplies, where every house had to have its own power generator, bottled gas and water filtering systems. That sounds like a remote, poor, and sparsely populated country, and certainly not like the UK. But this is precisely how the UK behaves in the all-important area of heating.

This is a country where most people actively prefer to generate their own central heating and hot water supply at home using their own separately maintained boiler. But there is a more joined-up alternative. With district heating, or district energy systems heat is produced from a centralised source, or network of sources, and literally piped out to individual buildings, including homes.

The most obvious advantages lie in the cost, with big economies of scale and the potential to use heat (e.g. from industry or from power generation) that would otherwise be wasted, and in terms of the environment. It is much easier to run a central plant using renewable energy sources than it is for thousands of separate boilers, and some renewable energy generating process, such as anaerobic digestion of food waste are only practicable on a large scale.

A heat network is also more flexible. For example, heat generated from ‘unreliable’ sources, like solar or wind, can be more easily and cheaply stored on a large scale. Obviously there are costs, most obviously that of running the heat out to buildings over a wide area, which can easily run to £1,000 per metre. But the UK, easily the most densely populated of the larger European countries, and with a cool climate and a lot of older houses that are hard to insulate, is surely one of the best placed to really go to grasp the advantages.

And yet in the UK, less than 2% of homes are currently connected to a heat network, a share that has been growing only gradually in recent decades. This compares with 8% in France, 12% in Germany, 42% in Sweden, and 61% in Denmark.

In fact, in the whole of Europe north of the Alps and Pyrenees, the only countries with a share as low as the UK are Ireland – where housing has been heavily influenced by links with the UK – and Norway, which has almost limitless hydro-electric power.

The British Department of Energy and Climate Change and the Scottish Government both recognise the potential benefits of district heating, but there are some critical barriers to overcome if district heating is to rise to levels even close to those found elsewhere.

Some of these are practical. A high proportion of the population live in individual houses which are more expensive to connect than flats. More homes are privately owned which means that unless there are strong incentives or even a degree of compulsion it is hard to persuade people to connect. Of course, a critical factor here is that it is not normally cost effective to connect individual buildings to a heat network in an incremental or piecemeal way. In Denmark, which leads Europe in district heating, households can sometimes be obliged to adopt it.

This leads to perhaps the biggest issue that district heating needs to address if it is to become mainstream in the UK. The popular expression that 'an Englishman’s home is his castle' was always something of a romantic exaggeration, but it reflects a widespread ideal, supported in the rest of the UK as well. This strong tradition of individualism has been reinforced in recent decades by governments that have become more reluctant for ideological reasons to introduce stringent regulations, let alone to intervene directly.

It is interesting that the two areas where district heating has made most progress are areas where there is more possibility of central control. One is in new-build, where planning guidelines can require more energy efficient heat sources to be considered. This is one reason why London, which is building far more new homes than most other parts of the UK, also has by far the highest penetration of district heating – though of course London’s scale and density are equally important.

The other sector which has led the development of residential heating from the outset is social housing. However this area has its limitations. Many early schemes were inefficient, giving district heating a bad name that has often been hard to challenge. The prevailing ideology also means that much social housing has either been sold off, or handed to smaller housing associations, and new social housing developments tend to be fragmented and so less suited for district heating.

Some useful steps have been taken. CIBSE last year launched a new Code of Practice for the specification and implementation of heat networks, but the processes for verifying and enforcing this are still widely seen as insufficient.

If it is serious about district heating, the UK government probably needs to be more pro-active. So far it has relied mainly on small carrots, such as grants to help local authorities fund feasibility studies. But if the UK wants to even remotely approach the impact made by heat networks elsewhere in Europe, then there probably needs to be a stick as well, to point at local authorities, developers and perhaps eventually even home-owners, though it will be a brave government indeed that will go that far.