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.