Before nations pin big hopes on biofuels, they must face stark realities, warn some scientist from the field. No matter what techniques are developed to expand biofuel feedstock, some basic physical and physiological limitations will apply. Plants cannot be grown without three crucial resource inputs: light, water and nitrogen. Each of those inputs will be needed in substantial quantities, yet their availability in the field is limited. As important, so far plants make use of those resources only at established rates. In fact, the close relationship between the available amounts of these resources and the amount of plant mass they can produce—not human demand—will determine how much biofuel the world can produce.
Biofuels are produced from living organisms or from metabolic by-products (organic or food waste products). In order to be considered a biofuel the fuel must contain over 80 percent renewable materials. It is originally derived from the photosynthesis process and can therefore often be referred to as a solar energy source. There are many pros and cons to using biofuels as an energy source. This page contains articles that explore the many biofuel technologies.
Biomass or biofuel 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.
It is used to produce power, heat & steam and fuel, through a number of different processes. Although renewable, biomass often involves a burning process that produces emissions such as Sulphur Dioxide (SO2), Nitrogen Oxides (NOx) and Carbon Dioxide (CO2), but fortunately in quantities far less than those emitted by coal plants. However, proponents of coal plants feel that their way of doing it is a lot cheaper and there is a lot of dispute over this.
For instance, should a crop such as peanuts be used to make fuel, or would the villagers be better off eating the peanuts? Or selling them? Should they press them to produce oil, for cooking or for selling or for fuel, and feed the high-protein seedcake residue to livestock, which in turn they can either eat or sell, while using the livestock wastes (and the crop wastes) to make compost to renew the soil, or to generate biogas for cooking and heating, or both? (The heat generated by the composting process can also be harnessed for heating.) Or should they grow a different crop altogether for its energy potential?
Should a grain crop be distilled to make ethanol fuel or should the villagers eat the grain? If they use the grain for livestock feed, it can be used for ethanol and still feed the livestock: the fermentation process to produce ethanol converts the carbohydrates in the grain while leaving the protein, with the addition of the high-protein yeast that does the fermenting. The residue is high-quality livestock feed, which can be supplemented by forage crops which humans can’t eat. This could mean improved utilization of the available resources.
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