The potential of vegetative biomass and technologies of preparation for utilization of biomass for energy purposes in Lithuania

Abstract

Energy input calculations show, that the technology of fuel manufacturing from traditional grasses is more advantageous than the technologies of fuel preparation from coarsestemmed plants–topinambour and sunflower stems. Plant biomass used for power purposes is the most important energy source. At present plant biomass used for power makes up approximately 90% of all the renewable energy used in Lithuania. The work aim is to determine the technical potential of plant biomass growing and usage for power purposes and to investigate the technologies for biomass use in Lithuania. Wood as a fuel is most widely used at present in Lithuania. Total energy value of Lithuania–produced wood fuel was 26.2 PJ. Wood fuel potential in the nearest decade will be 4-4.5 Mm³. Straw is another source of biomass fuel. About 0.5 Mt (million tons), i. e. 12-15 % of the total straw yield can be used as a fuel in Lithuania. Potential of straw as a fuel makes about 167.2 thousand toe. The resources of plant energy biomass may be supplied by specially grown plants: willows, perennial grasses, rapes cereals and sugar beets. 22 % of agricultural land can be attributed for this purpose. Biogas can be produced from plant biomass in anaerobic reactors. At a heat value of 22.6 MJ/m³ the total biogas potential from plant biomass in Lithuania would amount to 1.6 PJ. About 310 thousand ha can be used to grow plants for biofuel. The crop area of rapes as biofuel (rape methanol (ethanol) ester) production is 222 thousand ha. In 2004 Lithuania produced about 2 thousand toe biodiesel and about 1.6 thousand toe of bioethanol. The technologies of growing, harvesting and fuel production from traditional fed–type grasses and coarse-stemmed vegetative plants were evaluated and rational technique was selected. After energetic evaluation of the technologies it was concluded that the total energy input of growing and harvesting of grasses and legumes was equal to 8334 MJ/ha, topinambour stems–14378 MJ/ha and sunflower stems–11324 MJ/ha, respectively.