Third generation biofuels

Main article: Algae fuel
Algae fuel, also called oilgae or third generation biofuel, is a biofuel from algae. Algae are low-input, high-yield feedstocks to produce biofuels. It produces 30 times more energy per acre than land crops such as soybeans.[29] With the higher prices of fossil fuels (petroleum), there is much interest in algaculture (farming algae). One advantage of many biofuels over most other fuel types is that they are biodegradable, and so relatively harmless to the environment if spilled.
The United States Department of Energy estimates that if algae fuel replaced all the petroleum fuel in the United States, it would require 15,000 square miles (38,849 square kilometers), which is roughly the size of Maryland.
Second and third generation biofuels are also called advanced biofuels.
Algae, such as Chlorella vulgaris, are relatively easy to grow, but the algal oil is hard to extract. There are several approaches, some of which work better than others. See: Prospects for the Biodiesel Industry.