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11 Chapter One: Biomass

such as corn, starches, or vegetable oils, which are fermented into ethanol. Second- generation biofuels are made of nonedible, nonfood crops such as agricultural or forestry residue. The process of fuel conversion is a bit more involved than in first generation. Third-generation biofuels are sourced from algae, which, though still in development, shows great promise as a sustainable resource.

Dung cakes, made from the droppings of cows or buffalo, are burned as fuel in some parts of India.