As demonstrated here, microalgal biodiesel is technically
feasible. It is the only renewable biodiesel that can
potentially completely displace liquid fuels derived from
petroleum. Economics of producing microalgal biodiesel
need to improve substantially to make it competitive with
petrodiesel, but the level of improvement necessary
appears to be attainable. Producing low-cost microalgal
biodiesel requires primarily improvements to algal
biology through genetic and metabolic engineering. Use
of the biorefinery concept and advances in photobioreactor
engineering will further lower the cost of
production. In view of their much greater productivity
than raceways, tubular photobioreactors are likely to be
used in producing much of the microalgal biomass
required for making biodiesel. Photobioreactors provide a
controlled environment that can be tailored to the specific
demands of highly productive microalgae to attain a
consistently good annual yield of oil.