Landfill gas is being used to make liquid biomethane for use as a vehicle fuel - the first time it has been used like this in Europe.
Waste firm Sita and technology provider Gasrec are in the final stages of commissioning plant at Sita’s Albury landfill site in Surrey. The landfill produces some 2,500m3 of landfill gas per hour, and this will be used to make 5,000 tonnes of biomethane - enough to power 150 heavy goods vehicles.
The plant works by dewatering the landfill gas, then removing hydrogen sulphide, carbon dioxide and nitrogen. The remaining methane, about 95% pure, is liquefied. According to Richard Lilleystone, Gasrec’s chief executive, the resulting liquid biomethane cuts CO2 emissions by 70% compared to diesel, particulates by 90% and SO2 by 50%. The fuel is also around 30% cheaper.
The fuel is being used by Sita, haulage firm Hardstaff Group, as well as Sainsbury’s in one of its delivery trucks. It is also being trialled by waste company Veolia in a street cleaning vehicle in Camden, north London, to assess its performance in urban areas. All users have their own refuelling infrastructure at depots.
According to Stuart Hayward-Higham, Sita’s head of business development, the firm decided to develop the plant as the economic future for electricity from landfill gas is uncertain. "There are many ways of making electricity, many of which are better than waste," he said. From next April, electricity from landfill gas will only receive 0.25 renewable obligation certificates (ROCs) per megawatt hour of electricity generated. This compares to the current 1 ROC.
Using landfill gas to make transport fuel rather than electricity also offers a significantly larger reduction in CO2 emissions, says the Renewable Energy Association.
Sita and Gasrec are already looking for alternative markets for the liquid biomethane. "Our thinking has moved away from road fuels," said Mr Hayward-Higham. "We’ve started thinking it could be a general high calorific-value fuel, which could be used in local combined heat and power plants." Sita is discussing the possibility of such uses with the London Climate Change Agency (ENDS Report 397, p 28 ).
Gasrec plans a series of planning applications for plant at other UK landfills this year, according to Mr Lilleystone. But both firms recognise there is greater potential for using anaerobic digestion to generate biomethane.
Sita hopes to make three planning applications for anaerobic digestion facilities before the end of the year. These will treat commercial food waste, taking it from firms and returning the liquid biomethane to them. "We think a closed-loop process like that will be attractive to businesses," Mr Hayward-Higham said.
Organic Power’s anaerobic digestion demonstration plant in Somerset produces a methane-rich gas that is sold as a compressed natural gas for use as a transport fuel (ENDS Report 357, p 14 ). Some other companies are trying to make waste into a vehicle fuel. In July, chemicals giant Ineos announced it intends to make bioethanol from biodegradable waste within two years.
It is already operating a pilot plant in Arkansas capable of producing 120 tonnes of bioethanol a year, developed with biotech firm Bioengineering Resources. The plant works by gasifying waste, then passing the gases through bacteria to produce bioethanol. Ineos believes the technology is ready to be scaled up to a 100,000- to 150,000-tonnes -per-year plant.
In May Biogen received planning permission for a 41,000-tonne plant near Rushden, Northamptonshire. It will process commercial food waste to produce 1.5MW of electricity, and hopes to have the site operational in 2009.
Renderer Prosper de Mulder has also announced plans to build a network of AD facilities across the UK. It has submitted a planning application for the first, a 50,000-tonne plant in Doncaster that could produce 2MW of electricity for the grid.