CHARACTERISTICS OF DIFFERENT TYPES OF GASEOUS AND LIQUID BIOFUELS AND THEIR ENERGY-BALANCE

A review is presented of the current state of the art with regard to the production and characteristics of gaseous and liquid biofuels. Energy balances are given for gaseous biofuels such as producer gas and biogas, and liquid fuels such as ethanol and plant oils including their methylesters. In many cases, energy crops have potential not only for energy production, but sometimes also offer useful by-products in the form of animal feedstuffs, fertilizers and industrial feed stocks. The net energy gain depends on the extent to which all these products can be used, but is often positive for energy use alone. There may also be social and environmental benefits to be derived from the use of biofuels. © 1994 Silsoe Research Institute.