Biomass

Green plants are fixing (retaining) the solar energy by chemical transformation processes from solar light, water, minerals in the soil and CO2. This transformation occurs in the main by photosynthesis in green leaves (Chlorophyll). Initially, plants produce a sugar (glucose, also called dextrose) and then a “higher” sugar (polysaccharide), these are bigger carbon compounds (like cellulose). These represent the main components of biomass. People and animals also produce biomass by food intake.

Bioenergy sources exist in a variety of different forms. Among the fuels, there are:

• Wood and waste wood from forest thinning, forest management and felling, from sawmills or from recycled wood.
• Energy wood, i.e. specially cultivated, fast growing tree species like poplar and willow tree (also known as “short rotation trees.”)
• Agricultural residues (straw.)
• Specially cultivated energy crops on the set-aside areas.

Important liquid energy sources that, for instance, can serve as fuel:

• Plants containing sugar and starch for the transformation in ethanol.
• Oil-bearing plants like Rape and Sunflowers for the production of vegetable oil.

Gaseous energy sources to be mentioned:

• Biogas, which is composed from agricultural residues by microbial transformation (i.e. fermentation.)

The oldest and most well known procedure is the incineration of mainly carbon, fixed in the biomass and combines with the oxygen in the air. This chemical reaction releases heat.

The biomass incineration is CO2-neutral, but, as biomass results not only from pure carbon, but with each incineration, other substances are released.
Biomass can be chemically transformed: for instance, into wood gas with which motors such as the internal combustion engine can be propelled.