Armstrong and Tompkins applied their experience in automation and process control to develop what they believe will be a cost-effective photo-bioreactor. Armstrong said their projections show a 12.8 percent return on investment for a 1.6 megawatt (MW) unit, while a larger 5 MW system should provide a return on investment closer to 15 percent. An individual photo-bioreactor panel measures 4 feet wide by 6 feet high by 3 inches thick, with 550 panels contained in one cell and five to six cells covering an acre of land. The process utilizes automated harvesting, reducing the moisture content in a prescreening process to about 20 percent, before being pumped to a final screen and dried further if necessary prior to processing. The estimated yield per acre is between 95 and 125 tons of dried biomass per year, according to Armstrong.

via RWE plans to generate electricity from algal diesel – Biodiesel Magazine.