ENERGY ALTERNATIVES: RENEWABLE
ENERGY AND ENERGY CONSERVATION
TECHNOLOGIES
Techno-Economic Analyses of Bioenergy Systems
The fundamental forms of bioenergy use are
(i) Traditional domestic use for household cooking,
lighting and water heating (for bath). The efficiency
of conversion of the biomass to useful energy is
between 5 to 15%.
(ii) Rural industrial use in agro processing, bricks and
tile manufacture, and pig iron where the biomass is
considered as free energy source. There is generally
little incentive to use the biomass efficiently, so
conversion of feedstock to useful energy commonly
occurs at an efficiency of 15% or less.
(iii) Biological conversion, including anaerobic digestion
for biogas production and fermentation for alcohol.
The overall efficiency of biomass utilisation depends on the
moisture content of the fuel and type of stoves used. Freshly
cut wood contains about 25-60% moisture. The removal of a
kilogram of water from wood involves an expenditure of about
620-670 kcals of heat energy. It is noticed that a reduction
of 25% moisture in fuel wood causes a saving of nearly 15% of
fuel wood. It is observed that dried wood with moisture
content of 8% releases heat too fast and the whole log tends
to burn, bringing the flame out of the stove.