60,000 gallons per (acre-year)?

from Fadhil M. Salih, ClearValue Companies:

Microalgal biomass placed in a well designed production system and located in a tropical zone can be in the region of 1.5 kilograms per cubic meter per day or a lipid productivity of four grams per kilogram of culture per day and 2.8 grams per square meter per day (1,200 gallons per acre per year). The use of algae as energy crops has potential due to their easy adaptability to growth conditions, the possibility of growing either in fresh or marine waters and avoiding the use of land. Furthermore, two thirds of earth’s surface is covered with water, thus algae would truly be renewable option of great potential for global energy needs.

Reported microalgal efficiencies vary according to microalgal species and experimental conditions. Values of 2.3 percent, 4.7 percent, 5.6 percent, 6.9 percent, 8.1 percent, 9.4 percent, 9.6 percent and 15 percent have been reported. At 15 percent efficiency, productivity of about 60,000 gallons per acre per year is theoretically achievable. If this theoretical productivity is translated to reality, we can easily replace a great part of our daily energy requirement without sacrificing huge areas of fertile land that are intended to grow oil rich crops.