An experiment is under way that will soon see heat from tube train tunnels being used to heat homes and businesses around parts of Islington. It’s all part of the Bunhill Energy Centre, an experiment in modern electricity power plants that avoids dumping surplus heat into the atmosphere as waste, and instead pumps it via underground pipes to local homes. Completed in the winter of 2012, the 2km of pipes under the streets links a number of local council estates and a few businesses up to a single gigantic hot water tank.
By making use of what is known as a Combined Heat and Power plant, the council is currently using a gas powered electricity generator to produce electricity, and rather than venting the heat away, they use it to heat the hot water tank and distribute it to the local residents.
The aim is to maximise the efficiency of the power plant by using what is in most power plants a waste product — heat. Modern power plants tend to be far from where people live, thanks to the National Grid making that possible, but it also means that the heat created by turning fuel into electricity is wasted. Electricity is generated for sale to the National Grid, and the heat used to sell cheap hot water to the locals.
This is in part thanks to the fact that the local council blocks were built at the time with a centralised heating network instead of individual boilers in each flat. That made it much easier to pump hot water to the council blocks, where it would be easily distributed to the residents. Had they tried to wire up each individual flat, it would have been vastly more expensive to build.