The algae with which we are concerned are microscopic plants referred to as green algae found in all aquatic environments, including marine, freshwater and brackish water. Green algae (singular: green alga) are the large group of algae from which the embryophytes (higher plants) emerged. As such, they form a paraphyletic group, variously included among the Plantae or with the Protista. The green algae include unicellular and colonial flagellates, usually but not always with two flagella per cell, as well as various colonial, coccoid, and filamentous forms. In the Charales, the closest relatives of higher plants, full differentiation of tissues occurs. There are about 6000 species of green algae. Many species live most of their lives as single-cells, other species form colonies or long filaments.

The seminal work on algae-to-biodiesel was performed in the wake of our nation's first energy crisis (mid 70's to mid 90's) by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado, whose original mission for the algae project was carbon dioxide mitigation (Sheehan 1998).

During the early years of their program they discovered that some of the algae species were capable of producing 50% or more of their weight in lipids, under the proper growth conditions, and the program therefore transitioned from carbon dioxide mitigation to algae-to-biodiesel. The program included laboratory and field work to identify the most promising species and to optimize growth conditions for maximizing lipid yield per acre. Their key findings, over 30 years ago, were that it was possible to produce 30 grams of algae per square meter per day, at 30% lipids (Soy Beans are typically 20% lipids) content which would yield 4,000 gallons of biodiesel fuel per acre annually.