Thames Water CEO says there is ‘tremendous potential’ for warm sewage to heat up homes across London

London homes could be heated by sewage as Thames Water’s boss says there is “tremendous potential” for this initiative.

Cathryn Ross, the water firm’s CEO, told London Assembly members yesterday (Wednesday 13 September) that using sewage to generate heat is an “untapped resource” and the technology “is actually quite simple”.

Bosses at Thames Water said they are exploring how the firm could absorb the heat created by the disposal of sewage and turn it into power.

Sewage within London alone could create 10 terawatt hours of waste water heat - the equivalent of 40% of power generated by Hinkley C.

Ross said: “The most exciting thing is the potential to generate heat from effluent. That’s a tremendous untapped resource and the technology is actually quite simple.

“All you’re doing is using the fact that effluent is relatively warm because of where it comes from – you put a heat inverter around the sewer pipe and you can extract the heat from that.”

She added that the technology was at a “fairly early stage” but Thames Water Ventures company was working on it.

Liberal Democrat member Hina Bokhari questioned Ross on whether the cost savings created by such a project would benefit Thames Water’s customers when they receive their bills.

Ross confirmed that it would, saying that it was a regulatory requirement for schemes of that kind.

The aim of the City Hall committee’s meeting was to discuss ways in which the Thames and other London rivers could be better used to cut carbon emissions.

Ross suggested that floating solar panels could be placed on a number of Thames Water’s reservoirs in London to be used as an alternative power source.

She said: “We have something like 19 square km of reservoir surface within the M25. That’s a tremendous opportunity and we see the potential there to have up to one gigawatt of floating solar generation within the M25.”

At an earlier point in the meeting, Ross apologised for a water outage in west and south-west London that was occurring as the meeting was being held.

Thousands of people were left with no water or low water pressure, and some schools and libraries had to close due to a lack of water.

The company said the problems were caused by a power supply issue at its west London treatment works, adding that by last night (Wednesday 13 September) most properties’ water supply should have returned.

In the meeting Ross pledged that the company would conduct two reviews into the cause as well as the firm’s attempts to respond to it.