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Poo power to heat homes in West London as Thames Water continues to reduce its carbon footprint

Wednesday 17th January 2024 12:30

An aerial view of Mogden STW

Mogden Sewage Treatment Works

  • Thames Water unveils its second successful gas-to-grid project.  
  • Around 4000 homes in West London will be heated using converted sewage sludge from Mogden sewage treatment works starting early this year.   
  • This initiative is part of Thames Water’s commitment to reduce its carbon emissions across its operations thereby reducing its contribution to the causes of climate change. 

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.  
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. 
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. 

Diagram explaining the gas to grid process

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.” 
Alan Midwinter, SGN Senior Project Manager for Mogden said: "The successful commissioning of the Mogden biomethane plant is another important step towards a net zero future. SGN would like to thank all the Thames Water stakeholders and respective teams involved in the Mogden project for their invaluable input and support, it really has been a team effort. We hope that these projects highlight the potential that exists to capture and upgrade low carbon biomethane from wastewater to the benefit of the local community.” 

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