Biofuel energy works by using fuels derived from living or dead biological organisms. It is different from fossil fuels which have been “out” of the carbon cycle for a long time. There are different terms for bio power such as biomass and biofuel and there are also many different biofuels. For example, biodiesel, bioalcohol, biogas, syngas, myco-diesel, oilgae, etc. What they all share in common is that they’re derived from living/recently dead biological sources which are all a part of the carbon cycle.
The carbon cycle consists of four major reservoirs of carbon that are inconnected by pathways of exchange (fire, rain, evaporation, etc). These reservoirs are the atmosphere, the biosphere (defined to include fresh water and non-living/living organic material including soil carbon), the oceans, and the sediments. Check out the environmental impact of bio power as well.
Unlike wind, solar, hydro, etc which all have a dominant method of conversion to useful energy bio power has a lot of emerging technologies none of which are dominant. Biofuels are seperated into four generations currently and we’ll surely see fifth generation soon. Nothing beyond first generation is really being used outside of laboratories or even theory in some cases. The first generation biofuels are the “traditional” biofuels you might probably know about or have at least heard of.
First Generation: Made from seeds, grains, vegetable oil, animal fats, sugars, starch.
- Biodiesel: Produced from oils or fats using transesterification which results in a liquid similar to diesel. Can be used in any diesel engine.
- Bioalcohol: Produced through the actions of microorganisms and enzymes through fermentation of sugars, straches, and cellulose.
- Biogas: Produced by anaerobic digestion of organic matter using anaerobes. Uses bio waste or energy crops as a process material.
- Syngas: Produced through a combined process of pyrolysis, combustion, and gasification. Biofuel is converted to carbon monoxide and energy using pyrolysis. Then a small amount of oxygen is introduced to help with combustion. After that gasification further converts the organic material to hydrogen and more carbon monoxide. The end product is a gas mixture which is more efficient than direct combustion.
- Solids: Burned directly in stoves or steam engines. Simple example being firewood burned to cook over.
Second Generation: Made from non-food crops, waste biomass.
The main idea behind second generation biofuels is to avoid crops that are consumed by humans. For example, poplar or inedible waste products like citrus peels or sawdust.
Third Generation: Made from algae.
Third generation biofuel is entirely focused on algae. Algae produces 30 times more energy per acre than crops like soybeans. The drawback to this is that algal oil is hard to extract but processes are improving.
Fourth Generation: Genetically engineering organisms to produce fuels.
Producing fuel directly from carbon dioxide and conversion of biodiesel into gasoline using genetically engineered organisms are both examples of fourth generation biofuels.