District heating schemes have a mixed reputation in the UK, although they are firmly established in other Northern European countries.   That’s partly because some schemes, built in the 60s and never properly upgraded, don’t work very well.  Stories abound of residents whose only temperature control is to open the window, and people feeling free to use heating extravagantly because there is no individual metering.  It’s also partly because, with the advent of North Sea gas in the 1980s, small, single-dwelling boilers became more popular, with all the individual control they offer.   And the difficulty the UK has in funding and building city-wide infrastructures hasn’t helped either.

With climate change, the rise in gas prices and the increasing uncertainty of supply, its vital that we rethink our approach to heating our homes, particularly in cities.  Piping heat through the streets, as we do our gas and water, is normal in Vienna, Copenhagen, Berlin and Reykjavik but in London, we have only few small schemes, notably in Pimlico

44% of our electricity is generated using natural gas.  Of the fossil-fuel based technologies, its the cleanest and emits the least CO2, but even the best gas power stations only convert about 45% of the energy in the gas to electricity.  The rest goes straight up the cooling towers as wasted heat.   Some of the electricity is lost as it travels through the grid from remote power stations to our homes.  Overall, in 2009, 565TWh was lost on the electricity sytem to heat and transmission /distribution losses, with the loss to heat being by far the largest part of that.  That is MORE than the total amount of electricity supplied to consumers – industrial, domestic and transport combined.  If those losses could somehow be drastically reduced they’d take the  the UK’s carbon emissions down with them. (1)

The technology to do this is well-established and, unlike the pure renewable technologies, works well in virtually any setting, including inner cities.  Gas fired Combined Heat and Power (CHP)  units can be installed in building plant rooms to provide power and heat to the building.  These units achieve efficiencies of 80-90%, and because they can be located close to the users of electricity, transmission and distribution losses are all but eliminated.  Excess power is sold  to the national grid, but excess heat needs to go somewhere.  And so we need district heating schemes.

In London, the London Plan and local planning guidance encourage the installation of CHP in new buildings, and mandate connection to district heating schemes where they exist.    If there’s no local scheme though, they can only prepare for a future possibility.   There’s also a problem with the size of CHP unit they may be willing to put in.  If the building can’t make use of the heat for most of the year, then either the unit will need to be run below its specification, making the cost-benefit case more difficult, or the heat will need to be dumped somehow, probably to the atmosphere via noisy rooftop plant.  This appears to be the rationale behind the rather small 1.8MWe unit proposed for the UKCMRI building which is currently seeking planning permission in Somers Town.    Ideally, a larger unit would be installed, and Section 106 agreements made to start building a district heating scheme connecting the nearby blocks of flats.

Renewables purists will argue that natural gas is a fossil fuel too, and we need to decrease our dependence on it.  That’s true, of course, but if we managed to install enough gas CHP to decommission a large proportion of coal-fired stations, we would greatly reduce our emissions, and its a technology that can be deployed quickly and is well known.  Building the district heating schemes would be a legacy for the future, and could be used by other forms of heating when gas becomes too expensive, or once all the coal-fired stations are replaced.

We need to invest in district heating now, to allow CHP, to make use of industrial waste heat and to provide a better legacy for future generations than climate change.

(1) DUKES 2010