It is renewable energy made available from materials derived from biological sources. Though wood is still our largest biomass energy resource, the other sources which can be utilized include plants, residues from agriculture or forestry, and the organic component of municipal and industrial wastes. Even the fumes from landfills can be used as a biomass energy source. Biohydrogen is a potential biofuel obtainable from both cultivations and from waste organic materials. Though hydrogen is produced from non-renewable technologies such as steam reformation of natural gas (~50% of global H2 supply), petroleum refining (~30%) and gasification of coal (~20%), green algae (including Chlamydomonas reinhardtii) and cyanobacteria offer an alternative route to renewable H2 production.