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1.3. Energy from biomass

Biomass as solar energy accumulated chemically in vegetable or animal matter is one of the most precious and diversified resources on earth. It provides not only food but also energy, materials for construction, paper, pharmaceuticals and chemicals. according to the Directive 2001/77/EC of the European Parliament and the Council of 27 September 2001 on the promotion of electricity produced from renewable energy sources in the internal electricity market „biomass is the biodegradable fraction of products, waste and residues from agriculture (including vegetal and animal substances), forestry and related industries, as well as the biodegradable fraction of industrial and municipal waste”.

The primary production of renewable energy within the EU-27 in 2010 was 166.6 million tones of oil equivalent (toe) – a 20.1% share of the total primary energy production from all sources. Among renewable energies, the most important source in the EU-27 was biomass and waste, accounting for over two thirds (67.6 %) of primary renewable production in 2010 [1]. An increasingly careful and extended use of biomass can provide: a greater contribution to the primary energy delivery worldwide; the reduction of greenhouse gases and other potential environmentally friendly effects; opportunities for rural communities economic and social development; the mitigation of waste disposal related problems and a better resources use. The new European Directive (2009/28/EC) aims for generating 20% of the total energy consumption in UE from renewable resources, and to replace 10% of the amount of transportation fuels with bio-fuels by 2020.

There are two main types of biomass: waste products (any kind of plant or animal residue and the organic fraction of the solid municipal waste) and biomass resulting from energy crops. Only the agricultural residues that are not used as livestock feed and bedding, or soil amelioration can be used for energy production. The raw crop residues present some disadvantages when used as energy sources, for example: reduced thermal output, variation of properties and quality, fast combustion; difficult automatic continuous feed of the combustion chamber; large storage space and transport issues. In order to overcome these problems, a density increase by compression would be necessary (producing briquettes or pellets). Residues must be dried and chopped before processing.

Biomass can be converted into useful forms of energy using different processes that depend on the type and quantity of biomass feedstock; the desired form of the energy, environmental standards and economic conditions.

1.3.1. Biomass resources

the main resource of biomass is wood. In addition to the wood there is a large variety of resources, such as:

• energy crops:

  • short-rotation forestry: poplar, willow, eucalyptus;

  • arable crops: sugar cane, oilseed rape, sugar beet;

  • perennial crops: switchgrass (a perennial herb that grows in North America), Miscanthus or elephant grass (grass Uganda).

• residues:

  • wood from tree trimming;

  • straws and stalks from cereals;

  • other residues from food processing (sugar cane, tea, coffee, nuts, olives).

• wastes and by-products:

  • scrap of wood: wood chips, sawdust,

  • waste paper;

  • organic fraction of municipal waste;

  • used vegetable oils and fats.

• methane captured from landfills, from wastewater treatment plants and manure.

There is a high potential of biomass that can be further increased through better use of existing resources and increasing crop productivity. Table I presents the yields per hectare for several types of biomass and Table II - the yields of agricultural waste.

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