Energy is a vital component of any society, playing a pivotal role in all round development.The post- oil crises shifted the focus towards renewable resources and energy conservation. Biomass, as a plant biomass, is one such renewable source, which accounts for nearly 33% of a developing countrys’ energy needs. In India, it meets about 75% of the rural energy needs.
The biomass is a renewable energy source because the energy it contains comes from the sun. Through the process of photosynthesis, plants capture the sun’s energy. When the plants are burnt, they release the sun’s energy they contain. In this way, biomass functions as a sort of natural battery for storing solar energy. The plants can be grown specifically for energy use (known as first and third-generation biomass) or by using their residues (known as second-generation biomass).
The biomaterials and bio-energy have long been produced from plants. The development of oil from fossil fuel have replaced many of the traditional uses during the twentieth century. The prospect of oil supplies being exhausted and concern about the impact on the atmosphere. Addition of carbon in fossil fuels have resulted in renewed interest in the use of plants as direct sources of bioenergy and biomaterials.
Research is being conducted worldwide to develop biofuel crops that require less land and use fewer resources, such as water. One step to overcoming these issues is developing biofuel crops like corn, soybeans, crop residues, switch grass etc. to each region of the world. If each region utilized a specific biofuel crop, the need to use fossil fuels to transport the fuel to other places for processing and consumption will be diminished. Firing biomass instead of coal led to a 148% reduction in GWP.
Thus, the plants adapted to a wide range of available production environments are needed.
Grass species such as wheat and other major cereal crops provide yields of the order of 10 tonnes/ha/year of grain under favourable conditions. The higher biomass yield potential is around 20 tonnes/ha/year. Sugarcane and related species are C4 plants and probably the grasses with the highest yield potential identified to date. Sugarcane has the potential to yield in excess of 100 tonnes dry matter/ha/year.Maize and sorghum are potentially model genomes for research on the use of grasses as bioenergy crops. Corn is a popular feedstock for ethanol production. Corn and other high starch grains have been converted into ethanol for thousands of years, yet only in the past century has its use as fuel greatly expanded.
Soybean oil is a major feedstock for production of biodiesel. Numerous studies between 1980 and 2000 have shown the use of straight vegetable oil including soybean oil to cause carbon deposits and shorten engine life. Use of soybean oil for biodiesel was greatly influenced by promotion from U.S. soybean farmers through the United Soybean Board (USB) and subsequent creation of the National Biodiesel Board.
Woody biomass options include species such as poplar and willow with yield potentials of about 15 tonnes/ha/year. Eucalypt species have the potential to yield more than 100 tonnes/ha/year, comparable to the best grasses such as sugarcane. More than 700 Eucalypt taxa have been described with hybrids between these species displaying enhanced growth performance. The poplar and eucalypts are the emerging model genomes for woody plant development as bioenergy resources.
The first generation of biofuel production has been based upon the conversion of the storage carbohydrates (sugars and starch) in the plants into fuel, e.g. bioethanol. Oil from plants such as oilseeds has also been used, but the relatively low yields indicate that this is unlikely to be a sustainable source of fuel on a global basis. Engineering of improved oil composition may make these plants more suited to biodiesel production.
The use of storage carbohydrates from the edible parts of plants creates the potential for direct competition between food and fuel production. This avoids direct competition with food production and makes a much wider range of plants possible sources of biomass.
Bioalcohols are biologically produced alcohols most commonly ethanol and less commonly propanol and butanol are produced by the action of microorganisms and enzymes through the fermentation of sugars or starches or cellulose. Ethanol can be used in petrol engines as a replacement for gasoline; it can be mixed with gasoline to any percentage. Biobutanol (also called biogasoline) is often claimed to provide a direct replacement for gasoline, because it can be used directly in a gasoline engine (in a similar way to biodiesel in diesel engines). Methanol is currently produced from natural gas, a non-renewable fossil fuel. It can also be produced from biomass as biomethanol. The methanol economy is an alternative to the hydrogen economy compared to today’s hydrogen production from natural gas.
Green diesel, also known as renewable diesel, is a form of diesel fuel which is derived from renewable feedstock rather than the fossil feedstock used in most diesel fuels. Green diesel feedstock can be a variety of oils including canola, algae, jatropa and salicornia in addition to tallow. Green diesel uses traditional fractional distillation to process the oils, not using transesterification.
Biogas is methane produced by the process of anaerobic digestion of organic material by anaerobes.
It can be produced either from biodegradable waste materials or by the use of energy crops fed into anaerobic digesters to supplement gas yields. The solid byproduct, digestate, can be used as a biofuel or a fertilizer. Biogas can be recovered from mechanical biological treatment waste processing systems.
Landfill gas is a less clean form of biogas which is produced in landfills through naturally occurring anaerobic digestion. If it escapes into the atmosphere it is a potential greenhouse gas. Farmers can produce biogas from manure from their cows by using an anaerobic digester.
Second generation biofuels are biofuels produced from sustainable feedstock. Sustainability of a feedstock is defined among others by availability of the feedstock, impact on GH emissions and impact on biodiversity and land use. Many second generation biofuels are under development such as cellulosic ethanol, algae fuel, biohydrogen, biomethanol, DMF, BioDME, biohydrogen diesel, mixed alcohols and wood diesel.
The proper utilization of available biomass as energy crops in specific environments requires an analysis of available species and their suitability in available production environments. A systematic analysis of plant options for food, energy, conservation and other uses should include all plant species.
The use of biomass energy has the potential to greatly reduce greenhouse gas emissions. Burning biomass releases about the same amount of carbon dioxide as burning fossil fuels. However, fossil fuels release carbon dioxide captured by photosynthesis millions of years ago-an essentially “new” greenhouse gas. Biomass, on the other hand, releases carbon dioxide that is largely balanced by the carbon dioxide captured in its own growth. The use of biomass can reduce dependence on foreign oil because biofuels are the only renewable liquid transportation fuels available.
