Lost Rivers for Underground Energy

I was combing through the writings on my original Hidden Hydrology blog, with the idea of bringing in some of the ‘best of’ content still relevant today. This 2018 post, “Underground Energy For London” was worth reconsidering, focusing on a report that identified a significant potential latent in hidden hydrological systems, to provide heat and cut carbon emissions through tapping into underground lost rivers. The specifics came from a group called 10:10 Climate Action, who focused on using London’s now-buried rivers as a source of power, asking the question:

“But what if we could use them to power our city once again? Through the magic of heat pumps, London’s lost rivers could provide low cost, low carbon heating and cooling to the buildings above. They could help us solve the big challenge of decarbonising heat. There’s huge potential for London’s lost rivers to provide clean, efficient and reliable heating for the city – tackling climate change and air pollution. And of course the same technology can be used in other underground waterways like sewers in towns and cities across the country.”.

Unfortunately, the report, nor the group 10:10 Climate Action as far as I can tell, is no longer available online from the original source. I tracked down an online version, so you can download a copy here.

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The use of heat pumps is fairly common practice. Extracting heat from these now piped subterranean waterways, and using this heat for buildings and other uses is more novel, offering an potential alternative power option for London and other cities.

The idea was well-covered at the time: “Lost rivers could heat London to cut capital’s emissions” (The Guardian, 07.08.18) “ noted the potential for underground heat to “cut capital’s emissions”, and the articles “Underground river could heat Buckingham Palace” (The Times, 07.16.18) and “Could Buckingham Palace Be Heated By A Lost River?” (The Londonist, 07.11.18) echoed this, focusing on Buckingham Palace as a visible example of the potential for heating buildings. “London’s lost rivers could heat the city, reduce emissions.” (Earth.com, 07.10.18) took a slightly different slant, focusing on helping curb carbon emissions, similar to the article “A new way to tackle climate change? Heat from underground rivers in London could help cut the capital’s emissions, claim campaigners.” (Daily Mail, 07.09.18).

The concept had also already been implemented in some areas, including Borders College in Scotland, tapping into local wastewater, and the State Ministry Building in Stuttgart, Germany, which tapped into flow from the Nesenbach, a buried river adjacent to the site.  A map extracted from the report (image below) shows a number of the potential sites in London, including The Effra, Stamford Brook, The Tyburn, and the Fleet, all of which have potential sites for the use of these technologies.  Specific places include Buckingham Palace (mentioned in a few of the articles above), which would tap the Tyburn, Hammersmith Town Hall which flows above Stamford Brook, and other buildings like schools and site elements like heated swimming pools, which is currently being done in Paris. 

The following video explains the idea in a specific location, showing an example of a London pub that sits atop an ancient subterranean water source, using this heat pump technology for its heating and cooling for beer and wine.

There are questions on the cost-benefit, and each of these systems would require some infrastructure to be viable, however, it’s pretty exciting to consider the potential of these systems to contribute to energy savings and reduction of carbon emissions. The potential for savings of energy is significant. The Times article noted: “A report from the Greater London Authority concluded that water-source heat pumps could meet 4.8 per cent of London’s heat demand, with sewer heat offering another 6.7 per cent.”

The idea of giving back some of their benefits to the city, even while still being buried underground, is also worth exploration.  While the original report is over six years old, I think the idea is still one that seems worthy of revisiting around the globe, identifying projects that could utilize similar techniques, as we search for expanded tools to battle climate change and rising energy costs. I’d be interested to know if any readers know of other cities today using this for district or building scale systems, or projects that have explored this idea of tapping buried rivers in water and sewers for heating and cooling. Let me know if you have any that come to mind.

Note: This post was originally posted on Substack on 11/16/24 and added to the Hidden Hydrology website on 04/22/25.