"Natural gas and biogas are mixed in the same system. Natural gas will dominate initially, but the percentage of biogas will increase," Kreisel says.
Sludge with great potential
Raw materials for biogas include organic waste from households, industries and sludge. With a gasification process, almost all kinds of organic material can be converted, but the biogas must be upgraded to achieve the same quality as natural gas.
18 June 2009 22:00 GMT
Updated
25 November 2012 9:48 GMT
