Renewable heat from London’s underground rivers

A few months ago 10:10 presented the strikingly innovative idea of powering trains directly from solar power – a world first. This month they released a report detailing another smart idea – using London’s lost rivers as a source of heat.

London has several buried rivers, culverted and built over in the development of the city. Among them are the Walbrook, the Tyburn and the Fleet. Some of them surface here and there, others are more or less lost, only visible where they flow into the Thames. There have been calls to ‘daylight’ them in the past, but 10:10 have another use for them: heating.

Heat pumps capture low levels of heat and relocate it. Think of your fridge. The loop of refrigerant captures heat inside the fridge and moves it to the outside. The inside of the fridge cools, and the heat is released through the black-grated netherworld of dust and cobwebs at the back. What, yours isn’t like that?

A water-source heat pump installed on one of London’s underground rivers would absorb low-grade heat from the passing water, cooling it and transfering the heat to the buildings above. In summer, the process could run in reverse to provide low-carbon cooling.

This is not a new idea. There are several examples in the report, including Borders College in Scotland and the presidential palace in Paris. It’s a proven technology, and there are several places where it could be applied in London. Buckingham Palace is being refitted at the moment, and has a river nearby. Stamford Brook runs directly underneath Hammersmith Town Hall.

A couple of high profile examples like this, and other places might start to take notice. Maybe even Luton, where the venerable River Lea lies buried under the town centre. It flows past the cinema, the library, the job centre and parts of the university. Any one of them might want to take a long hard look at 10:10’s Lost Rivers report.


  1. This is an interesting idea. I am curious to know what ecological impact using the same system for cooling would have on surrounding bodies of water, though. If cooler air is being drawn off the water and pumped into the building, would that potentially raise the water temperature of the rivers then flowing on into the Thames? I know that, in the US at least, where warmer, treated, water is released back into stream systems, there is significant decreased in aquatic macroinvertebrates – important bioindicators of stream health…Did the authors address any of those types of concerns in 10:10?

    Star renewables from Glasgow are developing this technology with one installation up and running in Norway. Anywhere there is running water, heat can be extracted. Particularly useful are sewage works where the water is already warmed, giving a head start,

    The challenges include the scale of operation necessary to make this viable, digging up roads to install pipework and encouraging buy-in. Institutions like hospitals, colleges or swimming pools could encouraged to adopt this technology with financial incentives.

    1. Yes, when you think of all the heat that’s run out of the building in draining baths and showers, there’s lots of heat to be tapped in the sewers. Good to know there are people working in it, and thanks for the link.

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