The research on suitable alternative clean energy sources to substitute the use of fossil fuels is rapidly attracting a lot of attention. In this context a wide range of renewable energy sources are considered as options. Biogas is one of these renewable energy sources that is deemed a suitable alternative energy source for both developed and the developing world. In the developing world biogas can be useful particularly for household energy use for warming, cooking, and lighting and hence replacing traditional burning of firewood. However, finding suitable energy crops from which to extract...