Severn Trent has invested £15 million to build three biomethane plants to turn gas produced from sewage sludge, energy crops from contaminated land and food waste into a gas which can be injected into the grid.
The equipment and processes are already in operation at Strongford Sewage Treatment Works in Stoke and at Stoke Bardolph Sewage Treatment Works in Nottingham.
While Spondon Sewage Treatment Works is due to become operational when the food waste digestion plant, which is currently under construction is completed next year.
Martyn Lightfoot, renewable energy development engineer at Severn Trent, said: “This investment is all part of our programme to self-generate the equivalent of half of the energy we use by 2020.
“The biomethane process that takes place at these plants produces a renewable gas that is a fully sustainable resource and can be injected directly into the grid or use in nearby homes and businesses.”
He added: “These new plants will help us save around £3 million a year on our energy bills, and that saving will be passed on to our customers who already pay less than £1 a day for their clean and waste water services.”
Severn Trent said it has “invested heavily” in renewable energy in recent years and is now leveraging “expertise” to generate both energy and income.
Each plant will produce up to 500m³ an hour of biomethane from 1,000m³ of biogas and will operate 24 hours a day, every day of the year. The green gas generated at all three sites is expected to be enough to heat more than 8,000 homes for a year.
Lightfoot, said: “We’ve been experts in anaerobic digestion for more than 60 years, and creating sustainable and clean energy is now a huge part of our business.
“It’s an area where we’re continuing to develop our knowledge and skills to make sure we continue to operate as a sustainable business long into the future.”
Severn Trent produces the “equivalent” of 38 per cent of the energy it uses and said it is “well on its way” to meeting its 50 per cent target.
In October, the company announced it had invested £60 million in thermal hydrolysis technology to generate 30 per cent more clean energy at its biggest sewage treatment works in Minworth, near Birmingham.