Vegetable oil can be obtained from more than 300 different plant species. Oil is contained mainly in fruits and seeds, yet still other origins exist. The highest oil yields can be obtained from tree crops, such as palms, coconuts, and olives, but there are a number of field crops containing oils. Climatic and soil conditions, oil content, yields and the feasibility of farm operations, however, limit the potential use of vegetable oils to a reduced number of crops.

Key economic characteristics that distinguish industrial biofuel from fossil fuel conversion systems are their general cost structures, scale economies, degree and type of subsidies, foreign exchange impacts, reliance on byproduct credits, and environmental externalities. To highlight major differences, the following discussion is organized around this set of economic and financial characteristics that differentiate the viability of biofuel from fossil fuel systems. Cost composition In Figure 2, a comparison of average costs for different sizes (20-50 MW) of conversion systems shows the relative importance of the major cost components - fuel, non-fuel and capital. Coal, oil-fired thermal and diesel-electric (at a high of $35.00/bbl and a low of $23.00/bbl oil prices)

Biofuel use in the transport sector Because transport fuels are almost exclusively petroleum derived, the rapid real price increases for oil in the 1970s left the transport sector in most oil-importing countries extremely vulnerable. As a result, many countries explored biofuel substitution options. Among the developing countries, Brazil’s aggressive sugarcane-to-ethanol programme provides the best available data and lessons on the economics of biomass-derived transport fuels.

A spatially resolved biomass burning data set, and related emissions of SO2 and aerosol chemical constituents was constructed for India, for 1996–1997 and extrapolated to the INDOEX period (1998–1999). Sources included biofuels (wood, crop waste and dungcake) and forest fires (accidental, shifting cultivation and controlled burning). PM emission factors were compiled from studies of Indian cooking stoves and from literature for open burning. BC and OM emissions were estimated from these, accounting for combustion temperatures in cooking stoves. SO2 emission factors were based on fuel sulphur content and reported

Biomass consumption 5.1. Biofuels Rural and urban biofuel consumption were estimated using respective per capita consumption at a district level, and results aggregated at the state and national level. Total biofuel (all fuels) consumption was 538MTyr_1 for 1996–1997. Rural fuelwood consumption was 293MTyr_1, with the states of Madhya Pradesh, Bihar, Orissa, Andhra Pradesh and West Bengal accounting 51% of total consumption. Urban fuelwood consumption was very low (9MTyr_1). Crop waste consumption was 116MTyr_1, with east-coast states (Tamil Nadu, Andhra Pradesh, Orissa and West Bengal) contributing 50% of the total. The estimated dung-cake consumption was 121MTyr_1 (Fig. 2) with Uttar Pradesh alone contributing 40MTyr_1. The