As aircraft are bound (still) to a liquid fuel (it has the most energy content per weight) alternative resources need to be converted into liquid fuels. The industry needs to consider which source is the best for biofuel, it needs to be relatively easy to 'harvest' compared to fossil fuel, with no impact on human food or water supply whatsoever and must be environmentally friendly.
Aircraft engines still cannot run on water but, indirectly, this water can be and is a source of algae. And these algae have a high yield compared to other biomass sources which makes them very interesting to the energy industry. A big advantage of many biofuels over 'normal' fuel types is that they are biodegradable, and if spilled harmless to the environment.
Boeing and Industry Study Shows Biofuels Perform Effectively as Jet Fuel. Read about it in the article below.
Excerpt from the document:
LE BOURGET, France (PRNewswire-FirstCall): Boeing (NYSE: BA) and a team from across the aviation industry today released high-level elements of a study that shows that sustainable biofuels analyzed in a series of pioneering test flights performed favorably in comparison to petroleum-based fuel.
According to the study, Evaluation of Bio-Derived Synthetic Paraffinic Kerosene (Bio-SPK), a series of laboratory, ground and flight tests conducted between 2006 and 2009 indicated the test fuels performed as well as or better than typical petroleum-based Jet A. The testing included several commercial airplane engine types using blends of up to 50 percent petroleum-based Jet A/Jet A-1 fuel and 50 percent sustainable biofuels.
To continue reading see the pdf below: