Bio-energy" redirects here. For the term bio-energy in the context of non-mechanist philosophy or alternative medicine, see Vitalism.
For articles on specific fuels used in vehicles, see Biogas, Bioethanol, Biobutanol, Biodiesel, Straight vegetable oil, and Wood gas generator.
Saab 99 running on wood gas. Gas generator on trailer.
Renewable energy
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Biofuel is defined as solid, liquid or gas fuel derived from recently dead biological material and is distinguished from fossil fuels, which are derived from long dead biological material. Theoretically, biofuels can be produced from any (biological) carbon source; although, the most common sources are photosynthetic plants. Various plants and plant-derived materials are used for biofuel manufacturing. Globally, biofuels are most commonly used to power vehicles, heating homes cornstoves and cooking stoves. Biofuel industries are expanding in Europe, Asia and the Americas। Recent technology even allows for the conversion of pollution into renewable bio fuel.
Biofuels offer the possibility of producing energy without a net increase of carbon into the atmosphere. This is because the plants used in the production of the fuel removed CO2 from the atmosphere; unlike fossil fuels, which return carbon that was stored beneath the surface for millions of years back into the atmosphere. Therefore, biofuel is, in theory, more carbon neutral and less likely to increase atmospheric concentrations of greenhouse gases. (However, doubts have been raised as to whether this benefit can be achieved in practice, see below). The use of biofuels also reduces dependence on petroleum and enhances energy security.[1]
There are two common strategies of producing biofuels. One is to grow crops high in sugar (sugar cane, sugar beet, and sweet sorghum[2]) or starch (corn/maize), and then use yeast fermentation to produce ethyl alcohol (ethanol). The second is to grow plants that contain high amounts of vegetable oil, such as oil palm, soybean, algae, or jatropha. When these oils are heated, their viscosity is reduced, and they can be burned directly in a diesel engine, or they can be chemically processed to produce fuels such as biodiesel. Wood and its byproducts can also be converted into biofuels such as woodgas, methanol or ethanol fuel. It is also possible to make cellulosic ethanol from non-edible plant parts, but this can be difficult to accomplish economically.
Biofuels are discussed as having significant roles in a variety of international issues, including: mitigation of carbon emissions levels and oil prices, the "food vs fuel" debate, deforestation and soil erosion, impact on water resources, and energy balance and efficiency।
Humans have used biomass fuels in the form of solid biofuels for heating and cooking since the discovery of fire. Following the discovery of electricity, it became possible to use biofuels to generate electrical power as well. However, the discovery and use of fossil fuels: coal, gas and oil, have dramatically reduced the amount of biomass fuel used in the developed world for transport, heat and power.[3] However, when large supplies of crude oil were discovered in Pennsylvania and Texas, petroleum based fuels became inexpensive, and soon were widely used. Cars and trucks began using fuels derived from mineral oil/petroleum: gasoline/petrol or diesel.
Nevertheless, before World War II, and during the high demand wartime period, biofuels were valued as a strategic alternative to imported oil. Wartime Germany experienced extreme oil shortages, and many energy innovations resulted. This includes the powering of some of its vehicles using a blend of gasoline with alcohol fermented from potatoes, called Monopolin.[citation needed] In Britain, grain alcohol was blended with petrol by the Distillers Company Limited under the name Discol, and marketed through Esso's affiliate Cleveland.[citation needed]
During the peacetime post-war period, inexpensive oil from the Middle East contributed in part to the lessened economic and geopolitical interest in biofuels. Then in 1973 and 1979, geopolitical conflict in the Middle East caused OPEC to cut exports, and non-OPEC nations experienced a very large decrease in their oil supply. This "energy crisis" resulted in severe shortages, and a sharp increase in the prices of high demand oil-based products, notably petrol/gasoline. There was also increased interest from governments and academics in energy issues and biofuels. Throughout history, the fluctuations of supply and demand, energy policy, military conflict, and the environmental impacts, have all contributed to a highly complex and volatile market for energy and fuel.
In the year 2000 and beyond, renewed interest in biofuels has been seen. The drivers for biofuel research and development include rising oil prices, concerns over the potential oil peak, greenhouse gas emissions (causing global warming and climate change), rural development interests, and instability in the Middle East।
Biomass is material derived from recently living organisms. This includes plants, animals and their by-products. For example, manure, garden waste and crop residues are all sources of biomass. It is a renewable energy source based on the carbon cycle, unlike other natural resources such as petroleum, coal, and nuclear fuels.
Animal waste is a persistent and unavoidable pollutant produced primarily by the animals housed in industrial sized farms. Researchers from Washington University have figured out a way to turn manure into biomass. In April 2008 with the help of imaging technology they noticed that vigorous mixing helps microorganisms turn farm waste into alternative energy, providing farmers with a simple way to treat their waste and convert it into energy.[4]
There are also agricultural products specifically grown for biofuel production including corn, switchgrass, and soybeans, primarily in the United States; rapeseed, wheat and sugar beet primarily in Europe; sugar cane in Brazil; palm oil and miscanthus in South-East Asia; sorghum and cassava in China; and jatropha in India. Hemp has also been proven to work as a biofuel. Biodegradable outputs from industry, agriculture, forestry and households can be used for biofuel production, either using anaerobic digestion to produce biogas, or using second generation biofuels; examples include straw, timber, manure, rice husks, sewage, and food waste। Biomass can come from waste plant material. The use of biomass fuels can therefore contribute to waste management as well as fuel security and help to prevent global warming, though alone they are not a comprehensive solution to these problems.
Using waste biomass to produce energy can reduce the use of fossil fuels, reduce greenhouse gas emissions and reduce pollution and waste management problems. A recent publication by the European Union highlighted the potential for waste-derived bioenergy to contribute to the reduction of global warming. The report concluded that 19 million tons of oil equivalent is available from biomass by 2020, 46% from bio-wastes: municipal solid waste (MSW), agricultural residues, farm waste and other biodegradable waste streams.[5][6]
Landfill sites generate gases as the waste buried in them undergoes anaerobic digestion. These gases are known collectively as landfill gas (LFG). This is considered a source of renewable energy, even though landfill disposal is often non-sustainable. Landfill gas can be burned either directly for heat or to generate electricity for public consumption. Landfill gas contains approximately 50% methane, the gas found in natural gas.
If landfill gas is not harvested, it escapes into the atmosphere: this is undesirable because methane is a greenhouse gas with much more global warming potential than carbon dioxide.[7][8] Over a time span of 100 years, one ton of methane produces the same greenhouse gas (GHG) effect as 23 tons of CO2.[citation needed] When methane burns, it produces carbon dioxide in the ratio 1:1 -- CH4 + 2O2 = CO2 + 2H2O. So, by harvesting and burning landfill gas, its global warming potential is reduced a factor of 23, in addition to providing energy for heat and power.
It was recently discovered that living plants also produce methane.[9] The amount is 10 to 100 times greater than that produced by dead plants in an aerobic environment[citation needed] but does not increase global warming because of the carbon cycle.[citation needed]
Anaerobic digestion can be used as a waste management strategy to reduce the amount of waste sent to landfill and generate methane, or biogas. Any form of biomass can be used in anaerobic digestion and will break down to produce methane, which can be harvested and burned to generate heat, power or to power certain automotive vehicles.
A current project for a 1.6 MW landfill power plant is projected to provide power for 880 homes.[10] It is estimated that this will eliminate 3,187 tons of methane and directly eliminate 8.756 tons of carbon dioxide release per year. This is the same as removing 12,576 cars from the road, or planting 15,606 trees, or not using 359 rail cars of coal per year.
