Technical Report

Biogas from Energy Crops Digestion

January 2010

The world‘s energy supply – A future challenge

Currently some 80% of the world‘s overall energy supply of about 400 EJ per year is derived from fossil fuels. Nevertheless roughly 10–15% of this demand is covered by biomass resources, making biomass by far the most important renewable energy source used to date. On average, in the industrialised countries biomass contributes by some 3 –13% to the total energy supplies, but in developing countries this proportion is much higher. In quite a number of countries biomass covers even over 50 to 90% of the total energy demand. Biomass combustion is responsible for over 90% of the current production of secondary energy carriers from biomass. Liquid biofuels cover only a small part and the most used are ethanol and biodiesel. Ethanol is produced from sugar- or starch crops, while biodiesel is derived from vegetable oils or animal fats. Currently biogas plays a smaller, but steadily growing role. Traditionally applied for sewage sludge treatmentand stabilisation purposes, energy recovery from biogas was a welcome by-product. However, biogas has become a well established energy resource, especially through the use of renewable biomass i.e. “energy crops”. Since about 1950, biogas production from manure and /or energy crops, continued to develop as an important new farm enterprise.