Thames Water’s Mogden sewage treatment works (STW) in south west London has hit a major milestone by generating more than half the electricity it uses from the sewage it treats..

The STW site near Twickenham Stadium recently upgraded its three combined heat and power (CHP) generators. Together, the six-megawatt CHPs now produce enough electricity every day to power 15,000 homes from biogas emitted when the solid matter filtered out of sewage, known as sludge, is heated in an anaerobic digester – more than half of the total electricity consumed at the site.

Mogden CHP project manager, Ian Ruffell, said: “To have a sewage works as large as Mogden self-generating more than half of its own energy is a great achievement and it’s all from a source which will never run out – that being the waste our customers send our way each and every day.”

He continued: “To be a more sustainable and greener business, our focus is on generating more of our own renewable energy, using less of it and spending less, all of which will reduce our carbon footprint and keep costs down, which can only be positive news for our customers."

The Mogden upgrade is just one of a number of ways Thames Water is working towards its target of producing 33 per cent of the electricity it uses from renewable sources by 2020.

The company also generates energy using wind power and solar power, and hosts one of the world’s largest floating solar panel farms on its Queen Elizabeth II Reservoir on the outskirts of London. It also uses CHPs to generate electricity from sludge at 23 other sewage works and produces 24 per cent of its electricity needs from them.

The Mogden CHP upgrade project was recently recognised at the 2017 Anaerobic Digestion & Biogas Industry Awards.

Image: The three CHP engines at Mogden sewage treatment works. Photo: Thames Water