With skyrocketing price of crude fossil fuel (oil) which is currently hovering around $102/barrel, there is renewed interest and a sense of urgency in biofuels in many developing countries as a means of “modernizing” biomass use and providing greater access to clean liquid fuels while helping to address energy costs, energy security and global warming concerns associated with petroleum fuels.
Biofuels used today can be classified into three distinct groups or generation. First-generation
biofuels are made from grains, seeds, vegetable oil and sugar crops. Feedstock such as corn and wheat are processed to afford bioethanol. Seeds such as sunflower and canola are pressed to obtain oil which is called biodiesel can be directly used in diesel engines. Alternatively animal fat and used vegetable oil can be processed to biodiesel.
Second-generation biofuels are made from non-feedstock “lignocellulosic” biomass such as crop residues of wood, wheat, and rice or certain types of grass grown especially for generating energy. Since second generation biofuels are based on non-edible feedstock, the direct food vs. fuel competition is limited. Though second-generation biofuels are not operating on a commercial scale, they offer distinct advantage as the feedstock can be cultivated specifically for energy generation which is enabling higher production of non-edible feedstock per unit land area, and more of the above-ground plant material can be converted to biofuel, thereby further increasing land-use efficiency compared to first-generation biofuels. These basic characteristics of the feedstock hold promise for lower feedstock costs and substantial energy and environmental benefits for most second-generation biofuels compared to most first-generation biofuels.
Third generation biofuels are made primarily from algae, which can produce up to 30 times more energy per acre than land crops. Despite the amount of water needed for biofuel production, algae sources offer several advantages over other biofuels. Algae can produce more than 80 times more oil per hectare per year than, for example, corn. What's more, algae are not a widely used food source and are CO2-consuming organisms, making them a carbon-neutral energy source. Additionally, algae can feed off the CO2 emission from power plants and digest common water pollutants such as nitrogen and phosphorous.
In India as in many other tropical countries, the leading biofuel feedstock today is sugarcane molasses, which is processed to yield bioethanol that can be blended into gasoline (petrol). Sugarcane requires good land and large amounts of irrigation water, which are difficult for the poor to obtain. The poorest rural dwellers in India and Africa live in areas that are too dry for sugarcane cultivation. An alternative and improved variation of sorghum called sweet sorghum has been developed. Sweet sorghum is ideal for drier areas and can produce a good yield with only moderate levels of rainfall. Sweet sorghum is economically competitive with sugarcane molasses, emits less pollution from processing, and yields four times more net energy than maize grain.
Sweet sorghum yields grain as well as sugar. Rather than replacing land grown to food, the cultivation of sweet sorghum for biofuel could well stimulate increased yields of grain and stalk (excellent livestock feed after the sugar is extracted). If implemented effectively, this could re-invigorate a prime livelihood and food production option for tens of millions of poor small-holder farmers across the dry lands of the developing world.
Biodiesel is equally important as bioethanol. Fossil-fuel diesel accounts for 40% of India’s oil imports. Across the developing world, diesel trucks, pump engines, tractors, generators and many other diesel-fueled devices are major consumers of energy and major polluters. Two promising biodiesel crops are Jatropha (a shrub/small tree) and Pongamia (a mid-sized tree). These species can be grown across vast, underutilized, relatively low-quality rain fed lands in both India and Africa (often referred to as wastelands). Their seeds yield about 30% oil that can be used directly to power village diesel engines, or trans-esterified in processing facilities to be suitable for blending with fossil fuel diesel for wide consumer use. Both Jatropha and Pongamia are inedible and can be grown in areas unsuitable for food crops e.g. wastelands and village and field border areas, minimizing competition with them. According to the Government of India’s Department of Land Resources, the country has 63.9 million ha of wastelands that are potentially available for biodiesel crops.
Jatropha curcas belongs to the plant family Euphorbiaceae and it is not a native to India. There are more than 600 varieties of Jatropha. Jatropha is a Central America crop and it was introduced by the Portuguese in India and Africa. It grows into a shrub or small tree. Jatropha oil is toxic to humans. The oil was used mostly for lighting because it produces a very clear and clean flame. Jatropha oil can be used to light candles, for soap, and as a bio-pesticide in addition to its biodiesel potential.
Among the many species that can yield oil suitable for biodiesel, Pongamia pinnata has been found to be one of the most promising. Pongamia pinnata is a legume, belonging to the Papilionaceae plant family. It is widely found across India, and is native to the Asian subcontinent. As a legume it is nitrogen-fixing, which importantly contributes to its survival on poor soils and enriches the fertility of those soils. It is tolerant to water logging, saline and alkaline soils, and it can withstand harsh climates (medium to high rainfall). It can be planted on degraded lands, farmer’s field boundaries, wastelands and fallow lands. Pongamia seeds contain 30-40% oil and are inedible by animals, making it easier to establish in managed plantings. It is one of few nitrogen-fixing trees that produce high oil-content seeds. It is a medium-sized evergreen tree with a spreading crown and a short trunk.
The tree is widely planted for shade and as an ornamental in India. Its natural distribution is along coasts and riverbanks. It is also found along roadsides, canal banks and farmlands. It is a preferred species for controlling soil erosion and binding sand dunes because of its dense network of lateral roots. Its roots, bark, leaves, sap, and flowers are traditionally used for medicinal purposes. Pongamia oil can also be used for cooking fuel and lighting lamps. The oil is also used as a lubricant, water-paint binder, pesticide, and in soap making and tanning. The oil is used in traditional medicine to treat rheumatism, as well as human and animal skin diseases. It is effective in enhancing the pigmentation of skin affected by leucoderma or scabies. The leaves and press cake can be recycled to enhance soil fertility since they are high in nitrogen. The press cake also has pesticidal value, particularly against nematodes in the soil. Dried leaves are used as an insect repellent in stored grains.