FibreGen started out as a shell company Libra Natural Resources, which was going to invest in businesses in the natural resources sector, and it subsequently evolved the strategy to investing in waste to energy businesses. It joined Aim on 11 March 2005 just before the London Stock Exchange tightened up the rules for small shells. It raised £1.26m at 3p a share. Initial investments included coal supplier King Coal, which was acquired by Aim-quoted Coal International, Prometheus Energy, a producer of natural gas from coal mines and landfill sites which subsequently joined Aim, and the Westwood Fibre Products business that has ended up forming the core wood pellet-to-energy business in North America. The other assets were spun off to enable FibreGen to concentrate on the wood pellets business. Libra changed its name to FibreGen in 2008.