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Bangladesh has encountered several challenges, including issues like overpopulation, energy shortage, and global warming for the last few decades. Addressing the increasing energy demand has become a crucial concern because of rapid increase in population and lack of growth in the economic. The electricity production of a country heavily relies on fossil fuels, particularly natural gas, which makes up approximately 54% of the current installed capacity. Bangladesh is an agrarian nation and biomass stands out as a source of renewable energy having significant potential to mitigate the demand for heat and electricity. Biomass resources in the country mainly comprise animal dung, agricultural crop residuals, solid waste from municipalities and forest residues. The existing biomass resources contribute to producing a high amount of energy and content of around 1574.16 PJ of energy equivalent to 437.28 TWh of electricity in which agricultural residues, animal manure, municipal solid waste, and forest residues impart around 852.32 PJ, 399.04 PJ, 112.16 PJ, and 210.64 PJ of energy respectively. This paper explores the extent, possibilities, and technologies associated with biomass energy conversion. Additionally, the study delves into the several biomass projects that the government, as well as non-governmental groups, are working on for environmental sustainability along with plans, challenges, and methods that are being utilized to encourage biomass technologies across Bangladesh. [Display omitted] • The biomass potentiality in Bangladesh for heat and electricity generation is emphasized. • The energy scenario and necessity of alternative energy sources in Bangladesh are discussed. • The available energy conversion technologies from biomass in Bangladesh are presented. • The existing biomass resource content of around 1574.16 PJ (437.28 TWh of electricity) of energy. • The economic aspects and challenges of biomass conversion into energy are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Number of annual harvest days is a critical variable in the scheduling of year-round delivery of grasses to a biorefinery. It defines the number of harvest machines required and the size of satellite storage capacity. An increase in both these parameters increases capital cost and thus the average delivered cost of biomass for year-round operation. The objective of this study was to determine the impact (number of harvest machines required and storage capacity required) of several harvest scenarios for switchgrass (Panicum virgatum). Calculations were done for a database of potential production fields within a 48-km radius of Gretna, Virginia. Four harvest scenarios were chosen ranging from short, October–December to extended, July–March. The extended harvest required only 33 round balers while the short (October–December) harvest required 64; consequently, capital cost for extended-harvest balers was only 51% of the baler capital cost for the short season. Maximum required storage capacity was 75% of the total annual harvest for the short season and 44% for the extended season. Capital cost to build storage was reduced by 41% by selecting the extended harvest season. [Copyright &y& Elsevier]

Abstract: Renewable energy will play a crucial role in the future society of the 21st century. The various renewable energy sources need to be balanced and their use carefully planned since they are characterized by high temporal and spatial variability that will pose challenges to maintaining a well balanced supply and to the stability of the grid. This article examines the ways that future ‘energy landscapes’ can be modelled in time and space. Biomass needs a great deal of space per unit of energy produced but it is an energy carrier that may be strategically useful in circumstances where other renewable energy carriers are likely to deliver less. A critical question considered in this article is whether a massive expansion in the use of biomass will allow us to construct future scenarios while repositioning the ‘energy landscape’ as an object of study. A second important issue is the utilization of heat from biomass energy plants. Biomass energy also has a larger spatial footprint than other carriers such as, for example, solar energy. This article seeks to provide a bridge between energy modelling and spatial planning while integrating research and techniques in energy modelling with Geographic Information Science. This encompasses GIS, remote sensing, spatial disaggregation techniques and geovisualization. Several case studies in Austria and Germany demonstrate a top-down methodology and some results while stepwise calculating potentials from theoretical to technically feasible potentials and setting the scene for the definition of economic potentials based on scenarios and assumptions. [Copyright &y& Elsevier]

Abstract: Utilizing biomass from urban landscapes could significantly contribute to renewable energy needs. An experiment was begun in 2007 to evaluate the biomass production from a bermudagrass, Cynodon dactylon var. dactylon (L.) Pers., lawn in Woodward, Oklahoma USA and to estimate the potential biomass yield for the City of Woodward. Each year in April, the lawn was dethatched and fertilized. Mowing began in mid-to-late May and biomass dry matter (DM) yield was estimated by harvesting four 1 m × 16 m areas. In addition, the DM yield of fallen leaves and tree limbs from pruning operations were added to the lawn yield estimates for total annual biomass potential. These data suggest that during years of high growing season precipitation it was possible to harvest from 13.5 to 19.0 Mg of DM biomass per planted hectare from an urban landscape and 8.0 to 12.3 Mg of DM biomass per planted hectare in years with near normal precipitation and temperatures. It was estimated that the City of Woodward could generate about 3750 Mg of biomass dry matter in a normal rainfall year and about 6100 Mg in a high rainfall year if every homeowner collected their lawn thatch and clippings, and tree leaves, twigs, and limbs for bioenergy production. On the basis of a 10 Mg ha−1 annual DM yield, an estimated 164 million Mg of dry biomass material could be collected in the USA from planted urban areas. Biomass from urban landscapes is an untapped resource and further research is needed to fully explore its potential. [Copyright &y& Elsevier]

Abstract: We present a process model for a lignocellulosic ethanol biorefinery that is open to the biofuels academic community. Beyond providing a series of static results, the wiki-based platform provides a dynamic and transparent tool for analyzing, exploring, and communicating the impact of process advances and alternatives for biofuels production. The model is available for download (at http://econ.jbei.org) and will be updated based on feedback from the community of experts in biofuel-related fields. By making the assumptions and performance metrics of this model transparent, we anticipate this tool can provide a consensus on the energy-related, environmental, and economic performance of lignocellulosic ethanol. [Copyright &y& Elsevier]

Supercritical water oxidation (SCWO) is an effective, promising technology for destroying almost all kinds of organic waste with the advantage of high removal efficiency and low residence time, and without producing pollutant byproduct. The chemical energy of organic pollutants can be considered as an emerging renewable energy source. As a high-temperature and pressure process, an immense energy demand is required in the pressurization and preheating sections. On the other side, the reactor effluent has a great potential for energy recovery because of the great amount of heat released during the SCWO reaction combined with the previous energy input. Thus, SCWO is not only an organic waste treatment process but also an energy conversion and utilization system. The application of SCWO has been extended to the clean, efficient utilization of low-quality fuels such as high-sulfur coal, heavy oils, and biomass instead of conventional combustion, hydrothermal spallation drilling in geothermal energy production, and heavy oil recovery. However, energy consumption cost is still rather high in the actual process due to insufficient equipment performance, unreasonable energy system integration, and selection of an anti-corrosion and salt plugging reactor. Thus, a systematic, in-depth analysis on energy conversion and utilization in SCWO is conducted for the first time in the paper. The mechanism of exergy destruction analyses indicates that reducing enthalpy change and energy level difference are critical to reducing energy consumption. Suggestions on improving energy efficiency are proposed in the preheating stage, chemical exergy release, and reactor design. [Display omitted] • Energy conversion and utilization in each stage of an SCWO system are analyzed. • Research methods and evaluation parameters for energy utilization are summarized. • Main factors affecting energy efficiency are summarized and analyzed. • The mechanism of exergy destruction is analyzed to reduce energy consumption. • Suggestions on improving energy efficiency are proposed. [ABSTRACT FROM AUTHOR]

Abstract: A yield model for willow plantations for bioenergy production in Sweden was developed based on recorded production of 2082 commercial plantations during the period 1989–2005. The model predicts yield for the first, second and third harvest using oats (avena) production as agro-climatic index. The mean annual yields were 2.6, 4.2 and 4.5 oven dry tonnes (odt) per hectare during the first, second and third cutting cycles, respectively. The yield correlated inversely with the length of the cutting cycle. The results of the study show significant differences between growers, which suggest the importance of proper management in the establishment and tending of the plantations. Model estimates for 25% of the best growers vary from 4.0 to 6.3odtha−1 yr−1 in 5-year-rotation plantations during the first cutting cycle, and from 5.4 to 7.1odtha−1 yr−1 in 4-year-rotations for the second cutting cycle. The proposed model can be applied in policy making and for management planning. [Copyright &y& Elsevier]

Abstract: How large is the potential demand for bio-heat in the UK? Whilst most research has focused on the supply of biomass for energy production, an understanding of the potential demand is crucial to the uptake of heat from bioenergy. We have designed a systematic framework utilising market segmentation techniques to assess the potential demand for biomass heat in the UK. First, the heat market is divided into relevant segments, characterised in terms of their final energy consumption, technological and fuel supply options. Second, the key technical, economic and organisational factors that affect the uptake of bioenergy in each heat segment are identified, classified and then analysed to reveal which could be strong barriers, which could be surmounted easily, and for which bioenergy heat represents an improvement compared to alternatives. The defined framework is applied to the UK residential sector. We identify provisionally the most promising market segments for bioenergy heat, and their current levels of energy demand. We find that, depending on the assumptions, the present potential demand for bio-heat in the UK residential sector ranges between 3% (conservative estimate) and 31% (optimistic estimate) of the total energy consumed in the heat market. [Copyright &y& Elsevier]

Abstract: The diversification of different types and sources of biofuels has become an important energy issue in recent times. The aim of this work is to evaluate the use of two kinds of renewable feedstocks in order to produce biodiesel. We have analyzed the potential production of oil from two species of macroalgae considered as waste coming out from a lagoon system involved in eutrophication and from sunflower seeds. We have tested oil extraction yields of both feedstock. Furthermore, a comparison has been carried out based on the emergy approach, in order to evaluate the sustainability and environmental performance of both processes. The results show that, under present conditions, considering oil extraction yields, the production of oil from sunflower seeds is feasible, because of the lower value of transformity of the final product with respect to macroalgae. On the other hand, the results demonstrate that with improvements of oil extraction methodology, macroalgae could be considered a good residual biomass usable for biofuel production. [Copyright &y& Elsevier]

Abstract: Straw that is produced as a coproduct of cereal grain and grass seed production on 24,000km2 in the Pacific Northwest states of Idaho (ID), Oregon (OR) and Washington (WA) has potential as a bioenergy feedstock. Previous attempts to develop approaches to convert straw to energy based on transporting straw to a conversion facility were uneconomical. Rising energy prices and the availability of new technologies have renewed interest in converting these lignocellulosic residues to energy products, especially liquid fuels [Perlack RD, Wright LL, Turhollow AF, Graham RL, Stokes BJ, Erbach DC. Biomass as feedstock for a bioenergy and bioproducts industry: the technical feasibility of a billion-ton annual supply, 2005. http://feedstockreview.ornl.gov/pdf/billion_ton_vision.pdf (website accessed December 2007). ], but information on the distribution of these resources is lacking. Development of an economic approach to convert this straw to energy will require an assessment of the regional distribution of available straw to identify an appropriate scale of conversion technology that optimally reduces straw collection and transportation costs. We utilized county-scale US Department of Agriculture (USDA) National Agricultural Statistical Service (NASS) data to quantify total grass seed and cereal straw production in each county of ID, OR and WA, subtracted the county-specific quantity of field residue for each crop, and developed an estimate of available straw, that remaining after sufficient straw is returned to the soil for conservation. At current straw yields, over 6.5Mt of straw in excess of that required for conservation purposes are available in the region. This straw is distributed across the landscape at an average density of 2.4Mgha−1 and in many locations will require small- or local-scale technology to enable economical conversion of the feedstock to energy. [Copyright &y& Elsevier]