London’s lost rivers could heat the city, reduce emissions

Underneath London lies a network of tributaries that flow into the River Thames and River Lea. These rivers and waterways were once an important part of daily London life as they powered mills and provided water for cooking to city residents.

The rivers have since been buried under pavement and concrete as London expanded through the years, but there have been several calls to unearth the rivers so they can once again be used and enjoyed.

A recent report conducted by the climate charity 10:10 Climate Action and social enterprise Scene suggests that these rivers are an untapped source of low carbon energy that could provide heat to London’s neighborhoods with fuel pumps.

If heat pumps were employed, it could potentially create a surplus of clean energy to the city and help London meet its zero-emission goals.

“Of course, the water temperature is not warm enough to directly heat buildings. But through a combination of energy efficiency measures and the use of heat pumps, we have an incredible opportunity: lower costs, lower carbon emissions, better air quality, and greater energy resilience,” writes Louise Waters, Alex Schlicke and Vijay Bhopal, who authored the report.

While the use of heat pumps placed in London’s underground rivers could potentially provide low carbon heat, the Daily Mail noted that these pumps have never been used at a scale this large and the report did not consider the financial ramifications of such a project.

10:10 Climate Action explained the heat pump process and found that a sealed tube containing a gas refrigerant would be placed between a building and a nearby underwater river.

The refrigerant would change from a gas to liquid as it passed through the tube and release huge amounts of energy in the process, more than enough to meet the heating needs of even Buckingham Palace during the coldest days of the year.

The rivers carry the same name as the streets under which they currently lie such as the Fleet and Strand.

One of the rivers, the Effra, was once the second largest river in London and today it could provide heat to several city areas all year round.

“The Effra by Brockwell Park carries a sizeable flow – some 180 liters per second on average, rising to 250 liters per second at peak times – which represents a heat resource of around 3 megawatts,” the report authors stated. “Tapping into just a tenth of this resource could allow the lido to be kept at a comfortable temperature for swimming in the cooler spring and autumn months.”

London’s current mayor has stated that he wants the city to be a zero-carbon city by 2050, but reaching that lofty aim would require a major shift towards renewable energy and carbon regulations.

“The mayor has set ambitious targets for phasing out gas burning in London over the coming years and we are going to need every bit of low-carbon heat we can get our hands on to meet these goals,” Leo Murray, director of campaigns at 10:10, told The Guardian.

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By Kay Vandette, Earth.com Staff Writer