Renewable Diesel: Biodiesel' s Nightmare.

Until algae farms move from the research and demonstration stage, biodiesel usage is going to be tightly constrained by available feedstock. The feedstocks for biodiesel are oils and fats, which naturally occur in quantity only in animals or the seeds of plants. As such, the quantity of oil available is much smaller than the sugars, starches, and cellulose which occur not only in the seeds and fruits of plants, but also in the stems and leaves, and can be used to make ethanol. Because sugarcane contains the best ethanol feedstock, sugar in the stem (not just the fruit) of the plant, Brazilian ethanol can compete effectively with gasoline without subsidies.