Fast pyrolysis of biomass was “invented” in North America around 1979 with early work being performed by NREL and the University of Waterloo. A number of commercial and demonstration plants for flash pyrolysis are operating in North America at a scale of up to 1000 kg/h. Ensyn (Canada) are marketing commercial flash pyrolysis plants of up to 4 t/h throughput which are offered with a performance guarantee and a number of conditional sales have been concluded (9). Interchem were building a second generation 1360 kg/h demonstration plant in Kansas based on the NREL vortex ablative pyrolysis process (1°) but this is now understood to be shelved. There are other smaller scale activities at research and development scale which are listed in Table 4.1 and described later.