Biomass is a renewable resource that can be used to produce heat, electricity or biofuel because of its great heterogeneity. Unlike other renewable resources, which are converted into energy in the same place where the resource is located, biomass must be collected and transported to generation plants. This can be an advantage because it allows more flexible use of energy resources, but, in turn, makes the transport and logistics important factors in the final cost of energy. It is generally believed that the net emission of carbon dioxide produced by biomass energy is zero, because the CO2 emitted has previously been captured in the formation of organic matter.

According to origin of the resource to process, biomass is classified into the following groups:

  • Primary biomass: when biomass comes from energy crops, agricultural waste or forestry residues.
  • Secondary biomass:when the residue is generated by agribusiness and agroforestry. This group includes the waste generated by the livestock industry.
  • Tertiary biomass: these are the residues from manufactured products (from agribusiness and agroforestry) which are consumed by people or products that have already served their useful life. Thus, this group includes organic matter from landfills and municipal solid wastes and also includes sewage sludge.