what is biofuel?

A biofuel is a fuel from vegetable or animal raw materials from waste products of organisms or organic industrial waste. Distinguish:

liquid biofuel (for internal combustion engines, for example, ethanol, methanol, biodiesel);
solid biofuels (firewood, briquettes, pellets, wood chips, straw, husks);
gaseous (synthesis gas, biogas, hydrogen).
Generation plant feedstock for biofuels:

The first generation. Traditional raw materials with high content of fat and starch. The combustion of this raw material produces a large amount of energy. But the inconvenience of its use is quite significant: the depletion of soil and foodstuff.
The second generation. Wood, grasses, inedible parts of crop plants. The main value of such raw materials – high content of lingin and cellulose. Second-generation feedstocks can be either used immediately or processed into gas. Disadvantages – the necessity of using large areas.
Third generation. Algae. Advantages – no need to use land resources for growing, fast playback resources.