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The use of woody biomass in thermochemical conversion is still the most popular method of obtaining bioenergy from this material. Elemental composition has a significant effect on biomass quality and parameters of the combustion process. The aim of this study was to determine the content of selected macroelements (phosphorus, potassium, magnesium, calcium, sodium and sulphur), microelements (boron, copper, iron, manganese and zinc) and trace elements (cadmium, chromium, nickel and lead) in willow biomass of two different varieties and three clones, harvested in annual, biennial and triennial cycles in north-eastern Poland. The study found significant variability between varieties/clones and harvest cycles. Biomass of the UWM 200 clone of Salix alba in triennial harvest rotation had the best parameters as a potential fuel source; it was found to contain the significantly smallest concentrations of P, K, Na, S (1.48, 5.45, 0.08, 0.35 g kg −1 DM, respectively) and Fe, Cr, Pb (208.85, 4.91, 0.83 mg kg −1 , respectively). The content of all of the elements under study decreased significantly with an extended harvest cycle, and the differences, when comparing the triennial to the annual cycle, ranged from −9% to −29% for macroelements, from −7% to −48% for microelements and from −11% to −20% for trace elements. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to explore the magnitude of Zimbabwe's biomass resources available for energy production using thermochemical conversion route. This involved estimation biomass from crops, forestry, livestock and Municipal Solid Residues (MSR). A model for estimating biomass energy potential was developed in Microsoft Excel. The crop and forestry production and livestock data used as a basis of calculations was obtained from FAOSTAT. The biomass residues available for energy production were calculated from residues produced considering economic and environmental concerns associated with the removal of crop residues from land and current residue uses. The energy content was obtained by multiplying the available biomass by specific biomass energy content. The total biomass energy was estimated at an annual average of 413.2 PJ but only 279.5 PJ (23.8% crops, 17.8% crop residues, 45.2% forestry resources, 12.2% livestock residue and 1.0% MSR) is sustainably available. Of this energy 189.3 PJ (26.3% from crop residue, 47.9% from woodfuel, 6.4% from forestry residue, 18.0% from livestock residue and 1.5% from MSR) can be used for energy production without competing for resources with food/feed production and other biomass applications. This can meet approximately 48% of the current energy consumption. [Copyright &y& Elsevier]

Abstract: Bioenergy is seen as one of the key options to mitigate greenhouse gas emissions and substitute fossil fuels. Bioenergy is also an atypical energy source due to its diversity and inter-linkages with many other technological and policy areas. The goal of this paper is to analyze the Portuguese possibilities for bioenergy provision from biomass. The potentials of biomass, conversion technologies and legal framework are analysed and discussed. The result of this analysis shows that there are still unused potentials especially from forestry, which can contribute significantly to cover the bioenergy targets. However, the Portuguese experience with conversion technologies is limited to combustion, which is a drawback that must be solved so as to the bioenergy potential can be used. Research and Development projects, as well as demonstration projects are needed in order to improve the efficiency of the technological processes. At political level, Portuguese governments have been following the policies and strategies of the European Commission in the energy sector. However, energy crops market, due to the inter-linkage with agricultural policy, seems to need some additional political push. [Copyright &y& Elsevier]