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Several biofuels has been criticised on the basis of energy efficiency, that is, fuel production consumes more energy than its total energy content. Other biofuels that have greater final energy content than the amount of energy during production have also been similarly criticised. Proponents of biofuels have aimed similar criticisms at oil production in the tar sands of Alberta, Canada where over 100-million cubic feet of natural gas is burned every day to raise steam to extract oil from the earth. Steam is pumped into the tar sands to heat the ground before the oil begins to flow. Imperial Oil has recently been criticised for having suggested that Canada's federal government subsidize the cost of the Can$7.5-billion Mackenzie natural gas pipeline that will bring natural gas south from the Artic. Another company exploring for oil recently proposed to use nuclear energy to raise the steam so as to extract oil from the tar sands.
Alberta has become America's leading foreign supplier of oil and their energy intensive oil production practices have added new credence to the production practices of various biofuel programs. During the oil embargo of the apartheid era, South Africa experimented with corn-based biodiesel. Similar experiments were conducted in Brazil and involved a plant oil from the Amazon region. Biodiesel development is taking on new significance as the cost of transportation fuel is projected to remain high over the next few years. At the present time, some 24-million gallons of soydiesel and biodiesel are being produced annually in the USA and the volume is projected to exceed 1-billion gallons annually within 5-years.
The increase in soydiesel production comes at a time when the nutritional value of unfermented soy products is being questioned along with genetically modified soy plants that can be grown in non-native regions. The soy plant species is known to protect itself from long-term consumption by insects and herbivore animals by producing enzymes that attack their reproductive. Herbivores that have no other food source other than soy plants will see their numbers dwindle into extinction. Ongoing criticism of the long-term effects of unfermented soy products on people and animals is likely to cause a reduction in soy consumption in those markets. Progressively more soy production would be transferred to the projected future increased production of soydiesel fuel. A large future soydiesel/biodiesel market would likely be self-sustaining and require no government subsidies or tax incentives.
The prolific Kudzu vine that was imported from Japan several decades ago has overrun several regions across the USA. Numerous marsh regions of Eastern Canada and the USA have become home to an equally prolific European weed called Purple Loosestrife. These weeds cost next to nothing to produce and the crop yield quite generous. An equally prolific explosion of a tropical undersea weed has occurred in the Mediterranean Sea where no natural predator exists. This weed was likely brought into that sea in the ballast tanks of ships and is likely being nourished by fertilizer that for decades has run off farms and into rivers that flow into the Mediterranean Sea. These weeds and other transplanted prolific plant species may have potential to be suitable candidates for future ethanol and biofuel development programs.
There is much evidence to suggest that some plant or animal species that are native to one part of the world reproduce at a prolific rate after being transplanted into favourable foreign regions where they have no natural predators. Scope exists whereby some of the foreign weeds may be genetically modified and cultivated as commercial cash crops in harsher climates. Genetic modification could increase the yield of plant material that may be processes into some form of biofuel. A few regulatory barriers to may need to be overcome so as to achieve such an objective. Suitable genetically modified ocean weed could be cultivated in a location like the Gulf of California if authorization could be obtained from the Mexican government.
The variety of biofuel may be derived from the aforementioned weeds may be used in the solid state such as pellet fuel while some weeds may be processed into a liquid such as ethanol. Another alternative would be to compost or decay the weeds in large containers after harvesting and for the purpose of generate methane gas in very large containers. Suitable containers may include emptied salt domes that measure up to 5000-ft diameter by 25,000-ft high or the smaller versions known as salt jugs. Effluent from a variety of commercial animal farms that usually cause environmental problems may be added into these containers to assist in the generation of methane. The methane may be used as fuel for gas turbines that produce electricity. Alternatively, synthetic liquid fuel (sulphur-free syndiesel) may be also derived from the methane gas.
Agricultural plant waste and fibre material from plants and vegetation that have been pressed for their oil and other juices have been compressed into combustible biofuel pellets and used as fuel in pellet stoves. Plant material has successfully been used as fuel in gasifier combustion systems in thermal power stations and has proven to be a superior fuel for gasification than many types of coal fuel. There are several types of drought-resistant grass (switch grass) and weeds that have roots that grow up to 14-feet deep and have long leaves that are regularly harvested to produce combustible fuel pellets. Poultry litter and solid effluent from poultry farms outside London, England has successfully been used as fuel at the Thetford power station (250-Mw). A similar power station (50-Mw) is located near a region of turkey farms in Kentucky, USA.
A variety of weed plants can be produced at very low cost and for the purpose of being processed into some form of biofuel. Genetically modified varieties of such weeds may be cultivated in regions that may otherwise be unsuitable for crops. The roots of such modified weeds could be made saline resistant to allow diluted ocean water to be used to sustain such crops. The range of weeds that may eventually be used to produce biofuel may go beyond wood waste, agricultural plant waste material, Kudzu, Purple Loosestrife or ocean weed.
A variety of gaseous, solid and liquid fuels may subsequently be produced at competitive costs and in an absence of government subsidies, special tax incentives and protection from competition through regulation. If world oil prices remain high and rise to higher levels in the future, competitively priced biofuels may be expected to enter the transportation energy market.
