First Ever Renewable Gas From Sewage Sent to British Grid

British households are now cooking and heating their homes for the first time with renewable gas produced from sewage. Biomethane gas from Didcot sewage works in Oxfordshire will produce enough renewable gas to supply up to 200 homes.

The landmark project at Didcot – a joint venture between Thames Water, British Gas and Scotia Gas Networks – marks an important milestone in the UK’s efforts to decarbonise the gas grid and move towards a low-carbon economy. It is expected that this will be the first of many similar projects.

Biomethane from all sources will make a contribution to decarbonising the gas grid by delivering renewable heat to households through the existing gas network and central heating boilers. According to a study by National Grid, it could account for at least 15% of the domestic gas market by 2020.

Sewage arrives at the Didcot works from some of Thames Water’s 13.8 million customers to be treated and recycled back to the environment. Sludge, the solid part of sewage, is then treated further in warmed-up vats in a process called anaerobic digestion, where bacteria break down biodegradable material, yielding biogas.

Impurities are removed from the biomethane before it is fed into the gas grid. The whole process – from flushing a toilet to gas being piped to people’s homes – takes around 20 days. The project took six months to complete and cost £2.5 million.

“We already produce £15 million a year of electricity by burning biogas from the 2.8 billion litres a day of sewage produced by our 13.8 million customers. Feeding this renewable gas directly into the gas grid is the logical next step in our ‘energy from waste’ business,” points out Martin Baggs, chief executive of Thames Water. “What we have jointly achieved at Didcot is a sign of what is to come, which can be replicated across our network and indeed the whole country. Every sewage works in Britain is a potential source of local renewable gas waiting to be put to use.”

Leave a Comment