Mogden sewage sludge to heat home in West London | Local News | News | Teddington Nub News

Thames Water has announced sewage sludge will be used to heat homes in West London early this year, after successfully delivering its second gas-to-grid (G2G) project, at its Mogden Sewage Treatment Works (STW).  

The success of the gas-to-grid model established at Deephams STW in North London in 2021, where biogas is converted into biomethane to heat homes in Enfield, served as the blueprint for the project at Mogden.   

 Anna Boyles, Head of Catchment for Mogden, said: “Both Deephams and Mogden Sewage Treatment Works have set a remarkable example for environmental stewardship and innovation. The successful transformation of biogas into biomethane, heating homes across London, not only shows the dedication of our Mogden teams and SGN to delivering this project but also marks a significant step towards reducing our carbon footprint.”   

Currently serving over 2 million customers, Mogden is the third largest STW in the UK, and has the potential to reach and supply gas to 4000 homes in West London.  

This comes as part of the company’s commitment on energy transition, by transforming the way it creates and uses power to reach net zero carbon emissions by 2030. 

Thames Water has previously been under fire over its sewage spills around the country. The Guardian found that Mogden was the worst affected site, where 17.1bn litres of sewage was discharged into the river from 2020. The area contains a nature reserve, rare wildlife and areas where people swim and boat. 

In February 2023, £97m was invested to upgrade Mogden Sewage Treatment Works in to increase capacity and reduce the number of storm discharges. The move is part of Thames Water’s aim to halve its discharges by 2030.  

Gas to grid. (Photo: Thames Water)

How it works   

A byproduct of the sewage treatment process is sewage sludge, which is then digested to produce BioGas. Mogden STW then generates electricity with this BioGas via Combined Heat and Power (CHP) engines. The Gas-to-Grid plant, which will be managed by gas supplier SGN, intends to take a proportion of this BioGas and to ‘uprate’ it to export quality which is achieved by filtering, scrubbing and then compressing gas so it can be used as fuel for cooking and heating.  

 Cllr Katherine Dunne, Deputy Leader of Hounslow Council and Cabinet Member for Climate, Environment and Transport said: “The Mogden Sewage Treatment Works upgrade will reduce carbon emissions from the plant and is another positive step on Hounslow’s Pathway to Net Zero.  

“Our commitment to bold climate action is unwavering, and we’ll continue to introduce measures that enable the retrofit of council-owned buildings, schools, and our social housing. We welcome Thames Water’s ambitious work to further decarbonise its estate and the positive impact this will have for local communities.”   

Thames Water currently collects 4.6 billion litres of wastewater daily from c.16 million customers and predicts there will be a growing demand for biomethane, resulting in high use and a cost-effective way of using energy.  

Having cut emissions by almost 70% since 1990, Thames Water has also self-generated 536 billion watt hours of renewable energy in 2022/23, covering 27% of its own energy needs, which will provide a better environmental outcome for customers and help protect the water cycle for future generations.   

Thames Water

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