Engineering news
Construction of the “world’s first” commercially operating bio-substitute natural gas plant has started in Swindon, after National Grid’s Gas Distribution company signed a £6.3 million deal to help fund it.
The £25 million plant, which will make gas from household waste, is being run by Go Green Gas, and uses technology from firm Advanced Plasma Power.
In the plant, waste and biomass will be shredded and dried, and “recyclates” such as metals or dense plastics removed. The prepared feedstock will then be heated to convert it to a synthesis gas, or syngas, containing tars. The tars are also converted to syngas using a close-coupled gasifier and plasma converter, a carbon-lean process that uses very high temperatures of around 1,200°C in the presence of controlled amounts of steam, air and oxygen.
The syngas will then be cooled and heavy metals, ash and other contaminants removed. It then passes through a series of catalysed reactions to convert it into methane and CO2. The CO2 is removed, leaving a methane-rich green “drop in” gas that can be injected into the grid.
Once operational, the plant will provide fuel for a fleet of 40 trucks belonging to Howard Tenens, a logistics company. According to the haulier, this will cut its greenhouse gas emissions by 80%.
Go Green Gas plans to supply gas for residential and business use during the first half of 2018. According to the firm, when fully operational the plant will be able to reduce greenhouse gas emissions by more than 5,000 tonnes a year.
National Grid said the technology has the potential to provide 100TWh of green gas a year – enough to fuel all of Britain’s heavy goods vehicles or meet one third of its domestic heating demand.
Chris Train, chief executive of National Grid Gas Distribution, said: “Green gas-fuelled vehicles cause much less pollution than diesel, and making gas from household waste also reduces the amount of waste sent to landfill.”