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Abstract: One of the most desired aspects for power suppliers is the acquisition/sale of energy for a future demand. However, power consumption forecast is characterized not only by the variables of the power system itself, but also related to social–economic and climatic factors. Hence, it is imperative for the power suppliers to project and correlate these parameters. This paper presents a study of power load forecast for power suppliers, considering the applicability of wavelets, time series analysis methods and artificial neural networks, for both mid and long term forecasts. Both the periods of forecast are of major importance for power suppliers to define the future power consumption of a given region. The paper also studies the establishment of correlations among the variables using Bayesian networks. The results obtained are much more effective when compared to those projected by the power suppliers based on specialist information. The research discussed here is implemented on a decision support system, contributing to the decision making for acquisition/sale of energy at a future demand; also providing them with new ways for inference and analyses with the correlation model presented here. [Copyright &y& Elsevier]

• Isolated hybrid diesel-PV grids investigated at varying levels of PV penetration. • Effect of PV penetration on specific fuel consumption and payback period examined. • IEEE 30-bus configuration used with generation/load data based on measured data. • Results demonstrate similar fuel consumption for different dispatch strategies. • PV penetration above 50% enables a calculated payback period of fewer than 2 years. Isolated large communities in the Amazon region of Brazil are power by Islanded grids powered by diesel generator systems. The costs of these systems are high due to the complex and unreliable fuel supply chain. Including large-scale photovoltaic installations in these isolated grids have the potential to increase the reliability and reduce the cost of electricity. This paper investigates the impact of PV generation insertion on the specific consumption of isolated thermoelectric power plants. A diesel thermoelectric power plant (DTPP) of 4 MW, supplying electric energy to an isolated grid, was used as a case study. Five Photovoltaic penetration levels are evaluated, considering the operational regulatory constraints, three diesel generators (A, B and C), two daily solar irradiance profiles and annual solar irradiance profiles, and two dispatch strategies. The power plant loading range is bounded by the Brazilian regulatory framework to comply with fuel consumption efficiency measures and to guarantee the reliable operation. In the evaluated scenarios, PV penetration was not subject to power curtailment measures controlled by the DTPP. However, the power plant loading range considers both variation of photovoltaic generation and load. The results presented in this paper indicate that maintaining a higher number of machines in operation can make the DTPP more reliable to absorb the PV generation variations, enabling the growth of the PV penetration on the electric system, reducing the DTPP's fuel consumption and return on investment (payback) of the PV system without change significantly the DTPP's specific consumption. The results also show that the quality of the diesel generator is more important to keep specific fuel consumption low than the dispatch strategy used for a given PV penetration. The replacement of Generator A (less efficient) for B (more efficient) together the PV penetration of 50%, for example, can achieve a yearly fuel consumption reduction superior to 1 million liters. For the same PV penetration, an average annual reduction of 0.78 million liters in DTPP's fuel consumption can be reached, with PayBacks that could come close to 1.4 years. [ABSTRACT FROM AUTHOR]

Abstract: This paper assesses 13 different inputs for biodiesel production and shows that the highest cost currently associated with the processing of residual resources, as well as their small production scale, are compensated by their smaller procurement costs, by their immediate availability in the urban centers and by their larger potential for greenhouse gas emission reduction. Biodiesel production from residues can meet all technical international specifications, even the esterification process. Data Envelopment Analysis (DEA), the methodology used in this study, allows for the building of an efficiency index up through linear programming with multiple inputs and outputs, enabling the integration of sustainable development dimensions. The experts' conclusions were arrived at through restrictions on virtual weighting, with findings that allow the grading of alternatives. [Copyright &y& Elsevier]

There is consensus that the use of renewable energy must be expanded. More and more restrictions on the use of fossil derived fuels may open the way for an increased consumption of biomass event those so far not perceived as feasible, such some biomass residue. Energy derived from biomass residues may provide even more benefits because it may replace other sources of higher-grade energy while providing proper destination for residues. Biomass from pruning residue has been overlooked as an energy resource due to many limitations. This paper addresses the issue and the means for energy valuation of pruning residues while provides final destination for them. It presents a framework to overcome most of today's challenges across the world. A case study was carried out to determine the main constraints and how they can influence the decision-making process. The variety of urban pruning residues and their rate of generation, handling, storage, logistics, economic and environmental issues, institutional regulations for a small city in Southern Brazil were taken into consideration in the analysis. Pruning residues were sampled in the field, then handled, shredded, dried, specified, stored and burnt in a concurrent woodburning furnace for testing. The diagnostics of the constraints and the lab tests were summarized and organized in a framework that aimed to assess the energy valuation of pruning residues. Results show that with proper assessment tools, projects, biomass analyses and burning technology energy valuation of pruning residues can be feasible. • Energy valuation of biomass pruning residues is feasible given proper conditions. • A novel assessment framework provides routes to overcome most of today's challenges. • A case study of energy valuation of urban pruning biomass residue in Brazil showed feasible to generate 1 to 1.5 MWe. • Information and data of bulk density, moisture content, heating value, of residues of five urban tree species. • Estimate of opportunity costs of disposal of biomass pruning residues in landfills. [ABSTRACT FROM AUTHOR]