Availability of woody biomass

 

The estimates on the availability of woody biomass at the national level varies in a range from 15 to 25 million tons of dry matter in relation to the methodology adopted and sources of the initial data. The potential energy contribution is estimated to be 4 mtoe (million tons oil equivalent). In fact, though there are numerous studies and researches in the field of bio-energy forest, they are generally aimed at territorial limited contexts. That lacks an overview of the geographic distribution of demand and supply of wood fuel.The statistics produced by the GSE S.p.A. note that in the time period between 1999 and 2009, the number of plants using solid biomass (mainly wood chips) is increased according to an average annual rate of 7.8%. From 25 plants in 1999 to get up to 53 plants in Italy in 2009.Evolution of installed capacity and number of plants using solid biomassItaly from 1999 to 2009

Development of forest area

The last decade has seen a marked turnaround, due to the increase in prices of oil and LPG, increased consumption by some specific sectors (eg food) and the availability of technologies that increase yields in domestic heating and allow the use of plant biomass in the medium-large highly automated and policy incentives implemented by the state and regions.

Woody biomass from forests

The woody biomass for their localization in disadvantaged rural areas are a resource that requires a close link between their use and development policies of the marginal areas.In Italy it is estimated that the potential availability of woody material, whether in the form of raw material (the Italian forest area is about 10 million hectares representing 35% of the country) that the activity of forestry residues and wood processing , is very high and adequate to respond to decentralized energy needs with non-negative environmental impacts.Since the advent of methane, the use of wood as the main form of energy for heating has declined drastically and with it the development of an industry that was estimated to be marginal because the firewood was considered an obsolete product, to inelastic demand with respect to income, then destined to be marginalized from the market by the spread of other forms of energy. The use of wood energy from forests has been neglected by the forest policy also did not consider that the presence and development of a demand for firewood could be a powerful stimulus to the development of interventions to improve culture of many degraded forests , by, for example, start-up costs of coppice to altofusti, in addition to supporting forest economy, especially in the Apennine areas and foothills, was and remains fundamentally linked to forms of government to coppice, and thus the production of small assortments.

The exploitation of wood biomass

 
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.