Severn Trent’s AD plant starts producing power

Power is being generated at Severn Trent’s latest food waste digestion plant at Roundhill near Stourbridge, UK.

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’.

Each year, the new Stourbridge biogas plant will be able to process over 50,000 tonnes of food waste into renewable gas which will be injected into the gas network for use in homes and businesses.

It is the second food waste AD plant from Severn Water, the UK’s second largest water utility. The existing plant at Coleshill has been in operation since 2015.

“We’re really excited to see the new plant at Roundhill become operational,” said Chris Jellet, from Severn Trent.

“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 in into huge vats that effectively digest it, like 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 sent for further energy recovery.”

 

Washed, squashed, tested and injected

Biogas generated at Severn Trent’s plant is made suitable for domestic use with a complex process which sees the gas washed, squashed, tested and injected. The washing takes place at high pressure. The biomethane is then compressed, or ‘squashed’, to get it to the same pressure as natural gas. The testing phase sees a review of the energy composition of the gas, and a quality assessment.

After testing, an odour is added so it smell likes normal gas, before it is ‘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.

Jellet 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.”

Not resting on its laurels, construction work is already underway on Severn Water’s third food waste AD plant, at a site in Spondon in Derbyshire. That plant is expected to become operational in 2018.