Biofuels (biogas, bioalcohol, biodiesel) are made from plant biomass, and are more or less carbon neutral, since in burning they do not increase the overall CO2 content of the atmosphere but set free just the amount of CO2 that was fixed before in photosynthesis of the plant (Schiermeier et al., 2008). Thus, in recent years, plant biomass has gained growing importance as an alternative energy source. Main current sources of bioalcohol (mostly bioethanol) are sugars of sugarcane and starch of corn and wheat. Today, about 20% of the US corn harvest is used to make bioethanol. This covers about 2% of the US demand for transportation fuels (Chisti, 2007).

Biodiesel is made from plant oil, mainly from rapeseed, palm oil and jatropha. Biogas is produced from different kinds of biomass. However, a serious flaw in the ecobalance of traditional biofuels becomes obvious when the complete CO2 balance is calculated, i.e., when CO2 costs for seed, fertilisers, herbicides, irrigation, harvest and processing are taken into account. There is also growing concern in public discussion about the fact that the use of edible plants as energy sources may raise the prices of food. It is also rather questionable to cut down tropical rainforests for planting oil palms or jatropha when the plant oil is not processed locally but transported a long way to the industrial countries. Therefore, for making biofuels it is desirable to use plants (energy plants) with the modest requirements in soil quality and water supply and that grow under conditions and at places not suitable for crop plants. Ideally, the whole plant biomass can be used for fuel production and not just the special parts of plants such as oil-containing fruits as in rapeseed or oil palm ('first-generation energy plants'). 'Second-generation energy plants' are already available, such as many prairie grasses and microalgae.

Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

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