Severn Trent’s new food waste digestion plant starts generating green power
Friday 8 September
Severn Trent has started operations at its latest green gas plant in Roundhill near Stourbridge.
The new facility uses anaerobic digestion to turn food waste from local businesses and other customers that is unfit for human use into clean power.
The site will be able to turn almost 50,000 tonnes of food waste a year into renewable gas that will be injected into the network for use in homes and businesses.
It is Severn Trent’s second food waste anaerobic digestion plant, following on from the success of the existing plant in Coleshill which has been operating since 2015.
Chris Jellett, from Severn Trent, explains: “We’re really excited to see the new plant at Roundhill become operational.“Simply put, we take food that can’t be eaten or used for any other purpose from local businesses and waste management companies and put it into huge vats that effectively digest it, like in your stomach, to produce biomethane which then goes through another process to be converted into gas suitable for injection into the network as a new source of renewable gas.
“The process also makes sure that the food waste doesn’t end up going to landfill, with any packaging that we remove at the plant is sent for further energy recovery.
“We’ve got more than 60 years of experience of turning sewage into clean energy, and we’re now putting that to good use in our food waste plants.”
The company, which serves eight million people across the Midlands and mid-Wales, has invested heavily in renewable energy in recent years and is now developing this expertise to generate even more clean power.
The gas is made suitable for domestic use with a process which involves some very complex engineering techniques where it is washed, squashed, tested and injected. The gas is ‘washed’ at high pressure, it is then ‘squashed’, or compressed, so it is at the same pressure as natural gas and is then ‘tested’ for quality. Finally, an odour is added so it smells like normal gas.
Testing also includes a review of the energy composition of the gas. Once that has been done, it is finally ‘injected’ into the gas supply network.The new Roundhill site has a permit to recycle 48,500 tonnes of packaged and unpackaged food waste a year.
Chris added: “The plant will produce enough renewable gas to heat 2,700 homes for a year and enough renewable electricity to power 1,700 homes.
“Renewable energy is a really growing area for us and we currently generate the equivalent of more than a third of the energy we use through renewable sources and have ambitions to increase that to 50% by 2020.”
Severn Trent is continuing to invest in food waste anaerobic digestion plants, with construction work underway at a third site in Spondon in Derbyshire. That plant is expected to become operational in 2018.
The company generates the equivalent of a third of its energy needs through renewables sources, including more anaerobic digestion plants, small-scale hydro plants, solar farms and wind turbines.
For more information about Severn Trent’s approach to renewable energy visit www.stwater.co.uk/about-us/climate-responsibility/renewable-energy.