The
term "biomass" is indicated mainly vegetable organic matter, both
spontaneous and cultivated by man, land and sea, produced by the
processes of photosynthesis with the help of the energy of solar
radiation, water and various nutrients.The most abundant types of biomass energy use may be due to the following categories:•
the forest biomass and wood industry, resulting from cutting operations
and maintenance of the forest, the work of the sawmills, the wood
product processing;• agricultural byproducts such as straw, stalks, vine shoots, pruning branches, etc..;• agro-industrial residues, consisting of husks, grape, hazelnut, rice husks, etc.. from the food industry (rice mills, distilleries, oil mills);•
energy crops toward the production of herbaceous or woody biomass for
direct use (combustion) or for the production of biofuels (short
rotation forestry, oil and sugar).• the organic fraction of municipal waste, from the collection from which biogas can be produced.The
potential energy contained in biomass can be released directly as heat
in the combustion process (using the traditional and dominant), or
concentrated in a variety of solid, liquid or gaseous fuels, such as to
make it easier to transport and end use through biochemical or thermochemical processes.The
solutions vary by type of plant biomass, technology used and the final
product (only electricity, combined with heat, only thermal energy). For
example, are proven technologies to the direct combustion of biomass in
suspension in special furnaces, the grid of fixed or mobile bed of
fluidized bed, gasification, pyrolysis and carbonization, which could
achieve intermediate solid fuels, liquid and gaseous biogas production
by fermentation anaerobic.
Scheme of plant for the generation of electricity-powered solid biomassAlthough
the energy produced from renewable biomass is generally considered to
be due to the fact that the CO2 cycle is closed (the CO2 released during
combustion is equal to that fixed by photosynthesis during growth), in
reality the supply chain of any type of biomass requires
the consumption of fossil energy (embodied energy) is directly
proportional to the number of steps required for the preparation of the
product (growing, harvesting, processing, transport, etc..). In
general, taking into account the whole chain, with the energy obtained
from biomass may result in a savings of 50% to 80% CO2 compared to
fossil fuels.Assuming
that the development of renewable energy, lowering of CO2 emissions
perspective, it is essential that a goal should stretch the policies of
all nations, sectors and individual citizens with the adoption of
responsible behavior and a
major rethink on lifestyle, it is however considered that in addition
to the positive effects there are critical issues that must be carefully
evaluated and that any intervention that involves consumption of
environmental resources while renewable, requires a careful evaluation
of potential territorial.The
current role of energy from biomass in meeting the overall demand for
energy is an issue entered the political and economic debate by
investing environmental and social issues, as well as economic, such as
competition between biofuels and food production for the use of soil,
environmental sustainability in relation to biodiversity, deforestation
and emissions from the installation of large size plants for energy
production, speculation and distortion of international markets that are
likely to further weaken already fragile economies of third countries. You can then give rise to a truly sustainable only if a global and local level will be a balance between critical and drivers. The
production of heat or electricity and heat cogeneration systems for
decentralized small-medium sized and whose supply chain is linked to a
maximum radius of 50 km seems to be, at present, a viable way to
increase renewable energy production while minimizing environmental impacts and local resources.