There are species of SingleCelledAlgae which can grow in salt water, fresh water or anything in between.
In general, the smaller an organism is, the more energy efficient it is. For a given amount of light, you'll get far more BioFuel out of SingleCelledAlgae, than if your grow trees for Wood instead.
There are also ongoing investigations which suggest that some Algae can directly produce hydrogen, by alternating between PhotoSynthesis (which produces Oxygen) and Hydrogen generation (which requires anaerobic conditions). So, essentially, you could use SolarPower to generate Hydrogen pretty much directly. This is better in many ways than the BioFuelGenerator, which generates BioFuel which may need to be gassified.