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Energies, Volume 5, Issue 11 (November 2012), Pages 4251-4891

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Research

Open AccessArticle Experimental Characterization of the Poisoning Effects of Methanol-Based Reformate Impurities on a PBI-Based High Temperature PEM Fuel Cell
Energies 2012, 5(11), 4251-4267; doi:10.3390/en5114251
Received: 3 August 2012 / Revised: 9 October 2012 / Accepted: 18 October 2012 / Published: 24 October 2012
Cited by 9 | PDF Full-text (1349 KB) | HTML Full-text | XML Full-text
Abstract
In this work the effects of reformate gas impurities on a H3PO4-doped polybenzimidazole (PBI) membrane-based high temperature proton exchange membrane fuel cell (HT-PEMFC) are studied. A unit cell assembly with a BASF Celtec®-P2100 high temperature membrane [...] Read more.
In this work the effects of reformate gas impurities on a H3PO4-doped polybenzimidazole (PBI) membrane-based high temperature proton exchange membrane fuel cell (HT-PEMFC) are studied. A unit cell assembly with a BASF Celtec®-P2100 high temperature membrane electrode assembly (MEA) of 45 cm2 active surface area is investigated by means of impedance spectroscopy. The concentrations in the anode feed gas of all impurities, unconverted methanol-water vapor mixture, CO and CO2 were varied along with current density according to a multilevel factorial design of experiments. Results show that all the impurities degrade the performance, with CO being the most degrading agent and CO2 the least. The factorial analysis shows that there is interdependence among the effects of the different factors considered. This interdependence suggests, for example, that tolerances to concentrations of CO above 2% may be compromised by the presence in the anode feed of CO2. Methanol has a poisoning effect on the fuel cell at all the tested feed ratios, and the performance drop is found to be proportional to the amount of methanol in feed gas. The effects are more pronounced when other impurities are also present in the feed gas, especially at higher methanol concentrations. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
Open AccessArticle Exergy Analysis of an Intermediate Temperature Solid Oxide Fuel Cell-Gas Turbine Hybrid System Fed with Ethanol
Energies 2012, 5(11), 4268-4287; doi:10.3390/en5114268
Received: 10 July 2012 / Revised: 24 September 2012 / Accepted: 18 October 2012 / Published: 24 October 2012
Cited by 4 | PDF Full-text (1156 KB) | HTML Full-text | XML Full-text
Abstract
In the present work, an ethanol fed Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) system has been parametrically analyzed in terms of exergy and compared with a single SOFC system. The solid oxide fuel cell was fed with hydrogen produced from ethanol steam [...] Read more.
In the present work, an ethanol fed Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) system has been parametrically analyzed in terms of exergy and compared with a single SOFC system. The solid oxide fuel cell was fed with hydrogen produced from ethanol steam reforming. The hydrogen utilization factor values were kept between 0.7 and 1. The SOFC’s Current-Volt performance was considered in the range of 0.1–3 A/cm2 at 0.9–0.3 V, respectively, and at the intermediate operating temperatures of 550 and 600 °C, respectively. The curves used represent experimental results obtained from the available bibliography. Results indicated that for low current density values the single SOFC system prevails over the SOFC-GT hybrid system in terms of exergy efficiency, while at higher current density values the latter is more efficient. It was found that as the value of the utilization factor increases the SOFC system becomes more efficient than the SOFC-GT system over a wider range of current density values. It was also revealed that at high current density values the increase of SOFC operation temperature leads in both cases to higher system efficiency values. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
Open AccessArticle A Comparison of Wind Flow Models for Wind Resource Assessment in Wind Energy Applications
Energies 2012, 5(11), 4288-4322; doi:10.3390/en5114288
Received: 10 August 2012 / Revised: 22 October 2012 / Accepted: 23 October 2012 / Published: 29 October 2012
Cited by 10 | PDF Full-text (4555 KB) | HTML Full-text | XML Full-text
Abstract
The objective of this work was to assess the accuracy of various coupled mesoscale-microscale wind flow modeling methodologies for wind energy applications. This is achieved by examining and comparing mean wind speeds from several wind flow modeling methodologies with observational measurements from [...] Read more.
The objective of this work was to assess the accuracy of various coupled mesoscale-microscale wind flow modeling methodologies for wind energy applications. This is achieved by examining and comparing mean wind speeds from several wind flow modeling methodologies with observational measurements from several 50 m met towers distributed across the study area. At the mesoscale level, with a 5 km resolution, two scenarios are examined based on the Mesoscale Compressible Community Model (MC2) model: the Canadian Wind Energy Atlas (CWEA) scenario, which is based on standard input data, and the CWEA High Definition (CWEAHD) scenario where high resolution land cover input data is used. A downscaling of the obtained mesoscale wind climate to the microscale level is then performed, where two linear microscale models, i.e., MsMicro and the Wind Atlas Analysis and Application Program (WAsP), are evaluated following three downscaling scenarios: CWEA-WAsP, CWEA-MsMicro and CWEAHD-MsMicro. Results show that, for the territory studied, with a modeling approach based on the MC2 and MsMicro models, also known as Wind Energy Simulation Toolkit (WEST), the use of high resolution land cover and topography data at the mesoscale level helps reduce modeling errors for both the mesoscale and microscale models, albeit only marginally. At the microscale level, results show that the MC2-WAsP modeling approach gave substantially better results than both MC2 and MsMicro modeling approaches due to tweaked meso-micro coupling. Full article
(This article belongs to the Special Issue Wind Turbines)
Open AccessArticle Investigation on Electrostatical Breakup of Bio-Oil Droplets
Energies 2012, 5(11), 4323-4339; doi:10.3390/en5114323
Received: 18 June 2012 / Revised: 17 September 2012 / Accepted: 24 October 2012 / Published: 29 October 2012
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Abstract
In electrostatic atomization, the input electrical energy causes breaking up of the droplet surface by utilizing a mutual repulsion of net charges accumulating on that surface. In this work a number of key parameters controlling the bio-oil droplet breakup process are identified [...] Read more.
In electrostatic atomization, the input electrical energy causes breaking up of the droplet surface by utilizing a mutual repulsion of net charges accumulating on that surface. In this work a number of key parameters controlling the bio-oil droplet breakup process are identified and these correlations among the droplet size distribution, specific charges of droplets and externally applied electrical voltages are quantified. Theoretical considerations of the bag or strip breakup mechanism of biodiesel droplets experiencing electrostatic potential are compared to experimental outcomes. The theoretical analysis suggests the droplet breakup process is governed by the Rayleigh instability condition, which reveals the effects of droplets size, specific charge, surface tension force, and droplet velocities. Experiments confirm that the average droplet diameters decrease with increasing specific charges and this decreasing tendency is non-monotonic due to the motion of satellite drops in the non-uniform electrical field. The measured specific charges are found to be smaller than the theoretical values. And the energy transformation from the electrical energy to surface energy, in addition to the energy loss, Taylor instability breakup, non-excess polarization and some system errors, accounts for this discrepancy. The electrostatic force is the dominant factor controlling the mechanism of biodiesel breakup in electrostatic atomization. Full article
Open AccessArticle Design and Fabrication of a Novel Hybrid-Structure Heat Pipe for a Concentrator Photovoltaic
Energies 2012, 5(11), 4340-4349; doi:10.3390/en5114340
Received: 24 August 2012 / Revised: 21 October 2012 / Accepted: 23 October 2012 / Published: 29 October 2012
Cited by 6 | PDF Full-text (757 KB) | HTML Full-text | XML Full-text
Abstract
This study presents a design method to fabricate a novel hybrid-structure flat plate heat pipe (NHSP heat pipe) for a concentrator photovoltaic. The NHSP heat pipe is composed of a flattened copper pipe and a sintered wick structure, and a coronary-stent-like rhombic [...] Read more.
This study presents a design method to fabricate a novel hybrid-structure flat plate heat pipe (NHSP heat pipe) for a concentrator photovoltaic. The NHSP heat pipe is composed of a flattened copper pipe and a sintered wick structure, and a coronary-stent-like rhombic copper mesh supports the structure. The coronary-stent-like supporting structure enhances the mechanical strength and shortens the reflux path of the working fluid. Experiments demonstrate that the sintered capillary heat pipe reduces the thermal resistance by approximately 72%, compared to a traditional copper mesh-screen heat pipe. Furthermore, it can reduce thermal resistance by 65% after a supporting structure is added to the heat pipe. The results show that the NHSP heat pipe provided the best performance for the concentrator photovoltaic, which can increase photoelectric conversion efficiency by approximately 3.1%, compared to an aluminum substrate. Full article
Open AccessArticle Time Domain Modeling and Analysis of Dynamic Gear Contact Force in a Wind Turbine Gearbox with Respect to Fatigue Assessment
Energies 2012, 5(11), 4350-4371; doi:10.3390/en5114350
Received: 26 August 2012 / Revised: 23 October 2012 / Accepted: 23 October 2012 / Published: 1 November 2012
Cited by 7 | PDF Full-text (4986 KB) | HTML Full-text | XML Full-text
Abstract
The gearbox is one of the most expensive components of the wind turbine system. In order to refine the design and hence increase the long-term reliability, there has been increasing interest in utilizing time domain simulations in the prediction of gearbox design [...] Read more.
The gearbox is one of the most expensive components of the wind turbine system. In order to refine the design and hence increase the long-term reliability, there has been increasing interest in utilizing time domain simulations in the prediction of gearbox design loads. In this study, three problems in time domain based gear contact fatigue analysis under dynamic conditions are discussed: (1) the torque reversal problem under low wind speed conditions, (2) statistical uncertainty effects due to time domain simulations and (3) simplified long term contact fatigue analysis of the gear tooth under dynamic conditions. Several recommendations to deal with these issues are proposed based on analyses of the National Renewable Energy Laboratory’s 750 kW land-based Gearbox Reliability Collaborative wind turbine. Full article
(This article belongs to the Special Issue Wind Turbines)
Open AccessArticle A Novel Miniature Culture System to Screen CO2-Sequestering Microalgae
Energies 2012, 5(11), 4372-4389; doi:10.3390/en5114372
Received: 1 September 2012 / Revised: 23 October 2012 / Accepted: 23 October 2012 / Published: 1 November 2012
Cited by 5 | PDF Full-text (627 KB) | HTML Full-text | XML Full-text
Abstract
In this study, a novel 96-well microplate swivel system (M96SS) was built for high-throughput screening of microalgal strains for CO2 fixation. Cell growth under different CO2 supply conditions (0.2, 0.4, 0.8, and 1.2 g L−1 d−1), residual [...] Read more.
In this study, a novel 96-well microplate swivel system (M96SS) was built for high-throughput screening of microalgal strains for CO2 fixation. Cell growth under different CO2 supply conditions (0.2, 0.4, 0.8, and 1.2 g L−1 d−1), residual nitrate, and pH value of Chlorella sp. SJTU-3, Chlorella pyrenoidosa SJTU-2, and Scenedesmus obliquus SJTU-3 were examined in the M96SS and traditional flask cultures. The dynamic data showed there was a good agreement between the systems. Two critical problems in miniature culture systems (intra-well mixing and evaporation loss) were improved by sealed vertical mixing of the M96SS. A sample screen of six microalgal species (Chlorella sp. SJTU-3, Chlorella pyrenoidosa SJTU-2, Selenastrum capricornutum, Scenedesmus obliquus SJTU-3, Chlamydomonas sajao, Dunaliella primolecta) was carried out in flasks and the M96SS. Chlamydomonas sajao appeared to be a robust performer (highest cell density: 1.437 g L−1) in anaerobic pond water with 0.8, and 1.2 g L−1 d−1 CO2. The reliability and efficiency of the M96SS were verified through a comparison of traditional flask culture, M96SS, Lukavský’s system, and a microplate shaker. Full article
(This article belongs to the Special Issue Biomass and Biofuels 2012)
Open AccessArticle Regulatory Promotion of Waste Wood Reused as an Energy Source and the Environmental Concerns about Ash Residue in the Industrial Sector of Taiwan
Energies 2012, 5(11), 4390-4398; doi:10.3390/en5114390
Received: 11 September 2012 / Revised: 21 October 2012 / Accepted: 23 October 2012 / Published: 2 November 2012
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Abstract
The objective of this paper was to provide a preliminary analysis of the utilization of energy derived from waste wood in Taiwan, a highly industrialized country with a high dependence (over 99%) on imported energy. The discussion focuses on the status of [...] Read more.
The objective of this paper was to provide a preliminary analysis of the utilization of energy derived from waste wood in Taiwan, a highly industrialized country with a high dependence (over 99%) on imported energy. The discussion focuses on the status of waste wood generation and its management over the past decade. Findings show that the quantities of biomass waste collected for reuse purposes in the industrial sectors of Taiwan has exhibited an increasing trend, from about 4000 tons in 2001 to over 52,000 tons in 2010. Although waste wood can be reused as a fuel and raw material for a variety of applications based on regulatory promotion, the most commonly used end use is to directly utilize it as an auxiliary fuel in industrial utilities (e.g., boilers, heaters and furnaces) for the purpose of co-firing with coal/fuel oil. The most progressive measure for promoting biomass-to-power is to introduce the feed-in tariff (FIT) mechanism according to the Renewable Energy Development Act passed in June 2009. The financial support for biomass power generation has been increasing over the years from 0.070 US$/kWh in 2010 to 0.094 US$/kWh in 2012. On the other hand, the environmental regulations in Taiwan regarding the hazard identification of wood-combusted ash (especially in filter fly-ash) and its options for disposal and utilization are further discussed in the paper, suggesting that waste wood impregnated with chromated copper arsenate (CCA) and other copper-based preservatives should be excluded from the wood-to-energy system. Finally, some recommendations for promoting wood-to-energy in the near future of Taiwan are addressed. Full article
(This article belongs to the Special Issue Wood to Energy)
Open AccessArticle Analytical Investigation and Control System Set-up of Medium Scale PV Plants for Power Flow Management
Energies 2012, 5(11), 4399-4416; doi:10.3390/en5114399
Received: 17 September 2012 / Revised: 26 October 2012 / Accepted: 29 October 2012 / Published: 8 November 2012
Cited by 16 | PDF Full-text (1621 KB) | HTML Full-text | XML Full-text
Abstract
In the field of photovoltaic (PV) plants and energy conversion from renewable sources, a large part of the technical literature is more devoted to practical aspects (new solar cells, electrically driven PV panels, safety, reduction of parasitic currents, etc.) than to theoretical [...] Read more.
In the field of photovoltaic (PV) plants and energy conversion from renewable sources, a large part of the technical literature is more devoted to practical aspects (new solar cells, electrically driven PV panels, safety, reduction of parasitic currents, etc.) than to theoretical investigations. Despite this tendency, this paper presents a mathematical analysis of a medium scale photovoltaic power generation system connected to the distribution network and of its control system. In such a system, the conversion stage is unique due to the absence of a boost chopper. The conducted analysis leads to the interesting conclusion that the inverter used in the plant presents two degrees of freedom, easy to exploit in a control system in which the inverter simultaneously realizes the interconnection to the grid and the MPPT control. The structure of the control system is then presented, discussed and validated by means of numerical simulations. Full article
(This article belongs to the Special Issue Solar Energy Systems and Materials)
Open AccessArticle Coherency Identification of Generators Using a PAM Algorithm for Dynamic Reduction of Power Systems
Energies 2012, 5(11), 4417-4429; doi:10.3390/en5114417
Received: 15 September 2012 / Revised: 31 October 2012 / Accepted: 31 October 2012 / Published: 8 November 2012
Cited by 3 | PDF Full-text (309 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a new coherency identification method for dynamic reduction of a power system. To achieve dynamic reduction, coherency-based equivalence techniques divide generators into groups according to coherency, and then aggregate them. In order to minimize the changes in the dynamic [...] Read more.
This paper presents a new coherency identification method for dynamic reduction of a power system. To achieve dynamic reduction, coherency-based equivalence techniques divide generators into groups according to coherency, and then aggregate them. In order to minimize the changes in the dynamic response of the reduced equivalent system, coherency identification of the generators should be clearly defined. The objective of the proposed coherency identification method is to determine the optimal coherent groups of generators with respect to the dynamic response, using the Partitioning Around Medoids (PAM) algorithm. For this purpose, the coherency between generators is first evaluated from the dynamic simulation time response, and in the proposed method this result is then used to define a dissimilarity index. Based on the PAM algorithm, the coherent generator groups are then determined so that the sum of the index in each group is minimized. This approach ensures that the dynamic characteristics of the original system are preserved, by providing the optimized coherency identification. To validate the effectiveness of the technique, simulated cases with an IEEE 39-bus test system are evaluated using PSS/E. The proposed method is compared with an existing coherency identification method, which uses the K-means algorithm, and is found to provide a better estimate of the original system. Full article
(This article belongs to the Special Issue Electrical Power and Energy Systems)
Open AccessArticle Annual Electric Load Forecasting by a Least Squares Support Vector Machine with a Fruit Fly Optimization Algorithm
Energies 2012, 5(11), 4430-4445; doi:10.3390/en5114430
Received: 14 September 2012 / Revised: 18 October 2012 / Accepted: 2 November 2012 / Published: 8 November 2012
Cited by 30 | PDF Full-text (361 KB) | HTML Full-text | XML Full-text
Abstract
The accuracy of annual electric load forecasting plays an important role in the economic and social benefits of electric power systems. The least squares support vector machine (LSSVM) has been proven to offer strong potential in forecasting issues, particularly by employing an [...] Read more.
The accuracy of annual electric load forecasting plays an important role in the economic and social benefits of electric power systems. The least squares support vector machine (LSSVM) has been proven to offer strong potential in forecasting issues, particularly by employing an appropriate meta-heuristic algorithm to determine the values of its two parameters. However, these meta-heuristic algorithms have the drawbacks of being hard to understand and reaching the global optimal solution slowly. As a novel meta-heuristic and evolutionary algorithm, the fruit fly optimization algorithm (FOA) has the advantages of being easy to understand and fast convergence to the global optimal solution. Therefore, to improve the forecasting performance, this paper proposes a LSSVM-based annual electric load forecasting model that uses FOA to automatically determine the appropriate values of the two parameters for the LSSVM model. By taking the annual electricity consumption of China as an instance, the computational result shows that the LSSVM combined with FOA (LSSVM-FOA) outperforms other alternative methods, namely single LSSVM, LSSVM combined with coupled simulated annealing algorithm (LSSVM-CSA), generalized regression neural network (GRNN) and regression model. Full article
(This article belongs to the Special Issue Hybrid Advanced Techniques for Forecasting in Energy Sector)
Open AccessArticle Combustion Characteristics of Chlorine-Free Solid Fuel Produced from Municipal Solid Waste by Hydrothermal Processing
Energies 2012, 5(11), 4446-4461; doi:10.3390/en5114446
Received: 3 September 2012 / Revised: 24 October 2012 / Accepted: 24 October 2012 / Published: 8 November 2012
Cited by 1 | PDF Full-text (714 KB) | HTML Full-text | XML Full-text
Abstract
An experimental study on converting municipal solid waste (MSW) into chlorine-free solid fuel using a combination of hydrothermal processing and water-washing has been performed. After the product was extracted from the reactor, water-washing experiments were then conducted to obtain chlorine-free products with [...] Read more.
An experimental study on converting municipal solid waste (MSW) into chlorine-free solid fuel using a combination of hydrothermal processing and water-washing has been performed. After the product was extracted from the reactor, water-washing experiments were then conducted to obtain chlorine-free products with less than 3000 ppm total chlorine content. A series of combustion experiments were then performed for the products before and after the washing process to determine the chlorine content in the exhaust gas and those left in the ash after the combustion process at a certain temperature. A series of thermogravimetric analyses were also conducted to compare the combustion characteristics of the products before and after the washing process. Due to the loss of ash and some volatile matter after washing process, there were increases in the fixed carbon content and the heating value of the product. Considering the possible chlorine emission, the washing process after the hydrothermal treatment should be necessary only if the furnace temperature is more than 800 °C. Full article
(This article belongs to the Special Issue Waste to Energy Technologies)
Open AccessArticle A DFuzzy-DAHP Decision-Making Model for Evaluating Energy-Saving Design Strategies for Residential Buildings
Energies 2012, 5(11), 4462-4480; doi:10.3390/en5114462
Received: 19 September 2012 / Revised: 26 October 2012 / Accepted: 6 November 2012 / Published: 9 November 2012
Cited by 6 | PDF Full-text (1652 KB) | HTML Full-text | XML Full-text
Abstract
The construction industry is a high-pollution and high-energy-consumption industry. Energy-saving designs for residential buildings not only reduce the energy consumed during construction, but also reduce long-term energy consumption in completed residential buildings. Because building design affects investment costs, designs are often influenced [...] Read more.
The construction industry is a high-pollution and high-energy-consumption industry. Energy-saving designs for residential buildings not only reduce the energy consumed during construction, but also reduce long-term energy consumption in completed residential buildings. Because building design affects investment costs, designs are often influenced by investors’ decisions. A set of appropriate decision-support tools for residential buildings are required to examine how building design influences corporations externally and internally. From the perspective of energy savings and environmental protection, we combined three methods to develop a unique model for evaluating the energy-saving design of residential buildings. Among these methods, the Delphi group decision-making method provides a co-design feature, the analytical hierarchy process (AHP) includes multi-criteria decision-making techniques, and fuzzy logic theory can simplify complex internal and external factors into easy-to-understand numbers or ratios that facilitate decisions. The results of this study show that incorporating solar building materials, double-skin facades, and green roof designs can effectively provide high energy-saving building designs. Full article
(This article belongs to the Special Issue Energy Efficient Buildings and Green Buildings)
Open AccessArticle Supplementary Controller Design for SSR Damping in a Series-Compensated DFIG-Based Wind Farm
Energies 2012, 5(11), 4481-4496; doi:10.3390/en5114481
Received: 6 September 2012 / Revised: 29 October 2012 / Accepted: 7 November 2012 / Published: 13 November 2012
Cited by 3 | PDF Full-text (462 KB) | HTML Full-text | XML Full-text
Abstract
The increasing presence of wind power in power systems will likely drive the integration of large wind farms with electrical networks that are series-compensated to sustain large power flows. This may potentially lead to subsynchronous resonance (SSR) issues. In this paper, a [...] Read more.
The increasing presence of wind power in power systems will likely drive the integration of large wind farms with electrical networks that are series-compensated to sustain large power flows. This may potentially lead to subsynchronous resonance (SSR) issues. In this paper, a supplementary controller on the grid-side converter (GSC) control loop is designed to mitigate SSR for wind power systems based on doubly fed induction generators (DFIGs) with back-to-back converters. Different supplementary controller feedback signals and modulated-voltage injecting points are proposed and compared based on modal analysis and verified through root locus analysis to identify the optimal feedback signal and the most effective control location for SSR damping. The validity and effectiveness of the proposed supplemental control are demonstrated on the IEEE first benchmark model for computer simulations of SSR by means of time domain simulation analysis using Matlab/Simulink. Full article
(This article belongs to the Special Issue Smart Grid and the Future Electrical Network)
Open AccessArticle An Energy and Water Resource Demand Estimation Model for Multi-Family Housing Complexes in Korea
Energies 2012, 5(11), 4497-4516; doi:10.3390/en5114497
Received: 18 September 2012 / Revised: 27 October 2012 / Accepted: 7 November 2012 / Published: 13 November 2012
Cited by 6 | PDF Full-text (1515 KB) | HTML Full-text | XML Full-text
Abstract
This paper proposes and develops a residential energy and resource consumption estimation model in the context of multi-family residential housing in Korea using a multi-layer perceptron (MLP) neural network. Eight indicators are introduced which affect the energy and water resource usage characteristics [...] Read more.
This paper proposes and develops a residential energy and resource consumption estimation model in the context of multi-family residential housing in Korea using a multi-layer perceptron (MLP) neural network. Eight indicators are introduced which affect the energy and water resource usage characteristics of Korean residential complexes. The proposed model precisely estimated the electricity, gas energy and water consumption for each examined residential complex. In terms of validation, the results showed the highest level of agreement with actually collected datasets. The model shows promising prospects in providing necessary estimations, not only for optimally scaling and sizing energy- and water-related infrastructures, but also to promote reliable energy and resource savings through greenhouse gas (GHG) reduction planning in multi-family housing complexes. The model could also be of use in framing guidelines for the better planning of national or regional energy and resource policies and for forming a foundation of decision-making with definite references regarding the facility management of each apartment complex to enhance the energy and resource use efficiency at these locations. Full article
(This article belongs to the Special Issue Energy Efficient Buildings and Green Buildings)
Open AccessArticle Demand Side Management for Stand-Alone Hybrid Power Systems Based on Load Identification
Energies 2012, 5(11), 4517-4532; doi:10.3390/en5114517
Received: 5 September 2012 / Revised: 17 October 2012 / Accepted: 6 November 2012 / Published: 13 November 2012
Cited by 5 | PDF Full-text (876 KB) | HTML Full-text | XML Full-text
Abstract
Within the field of Distributed Generation (DG), stand-alone Hybrid Power Systems (HPS) are a suitable solution to provide energy to isolated facilities where the connection to a centralized grid is not affordable. The logical evolution of such systems involves the optimization of [...] Read more.
Within the field of Distributed Generation (DG), stand-alone Hybrid Power Systems (HPS) are a suitable solution to provide energy to isolated facilities where the connection to a centralized grid is not affordable. The logical evolution of such systems involves the optimization of power resources and related control strategies, but also enhancements concerning the management of energy loads. This paper introduces Demand Side Management (DSM) strategies specially designed for HPS. They are applied on a real and patented HPS that consists of PV panels, a diesel generator, an inverter and a set of batteries. DSM strategies are built up on a framework of distributed endpointdevices connected to a central control application where loads are identified according to their behavior. System network components, load definitions, the control application and DSM strategies are depicted. Finally, simulations show illustrative savings achieved by the application of some of the proposed strategies. Full article
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Open AccessArticle Electrical Double-Layer Capacitors in Hybrid Topologies —Assessment and Evaluation of Their Performance
Energies 2012, 5(11), 4533-4568; doi:10.3390/en5114533
Received: 17 August 2012 / Revised: 16 October 2012 / Accepted: 6 November 2012 / Published: 14 November 2012
Cited by 15 | PDF Full-text (1676 KB) | HTML Full-text | XML Full-text
Abstract
PHEVs and BEVs make use of battery cells optimized for high energy rather than for high power. This means that the power abilities of these batteries are limited. In order to enhance their performance, a hybrid Rechargeable Energy Storage System (RESS) architecture [...] Read more.
PHEVs and BEVs make use of battery cells optimized for high energy rather than for high power. This means that the power abilities of these batteries are limited. In order to enhance their performance, a hybrid Rechargeable Energy Storage System (RESS) architecture can be used combining batteries with electrical-double layer capacitors (EDLCs). Such a hybridized architecture can be accomplished using passive or active systems. In this paper, the characteristics of these topologies have been analyzed and compared based on a newly developed hybridization simulation tool for association of lithium-ion batteries and EDLCs. The analysis shows that the beneficial impact of the EDLCs brings about enhanced battery performances in terms of energy efficiency and voltage drops, rather than extension of vehicle range. These issues have been particularly studied for the passive and active hybrid topologies. The classical passive and active topologies being expensive and less beneficial in term of cost, volume and weight, a new hybrid configuration based on the parallel combination of lithium-ion and EDLCs on cell level has been proposed in this article. This topology allows reducing cost, volume, and weight and system complexity in a significant way. Furthermore, a number of experimental setups have illustrated the power of the novel topology in terms of battery capacity increase and power capabilities during charging and discharging. Finally, a unique cycle life test campaign demonstrated that the lifetime of highly optimized lithium-ion batteries can be extended up to 30%–40%. Full article
Open AccessArticle Non-Intrusive Demand Monitoring and Load Identification for Energy Management Systems Based on Transient Feature Analyses
Energies 2012, 5(11), 4569-4589; doi:10.3390/en5114569
Received: 19 October 2012 / Revised: 7 November 2012 / Accepted: 7 November 2012 / Published: 14 November 2012
Cited by 28 | PDF Full-text (2020 KB) | HTML Full-text | XML Full-text
Abstract
Energy management systems strive to use energy resources efficiently, save energy, and reduce carbon output. This study proposes transient feature analyses of the transient response time and transient energy on the power signatures of non-intrusive demand monitoring and load identification to detect [...] Read more.
Energy management systems strive to use energy resources efficiently, save energy, and reduce carbon output. This study proposes transient feature analyses of the transient response time and transient energy on the power signatures of non-intrusive demand monitoring and load identification to detect the power demand and load operation. This study uses the wavelet transform (WT) of the time-frequency domain to analyze and detect the transient physical behavior of loads during the load identification. The experimental results show the transient response time and transient energy are better than the steady-state features to improve the recognition accuracy and reduces computation requirements in non-intrusive load monitoring (NILM) systems. The discrete wavelet transform (DWT) is more suitable than short-time Fourier transform (STFT) for transient load analyses. Full article
(This article belongs to the Special Issue Smart Grid and the Future Electrical Network)
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Open AccessArticle Asymmetrical Interleaved DC/DC Switching Converters for Photovoltaic and Fuel Cell Applications—Part 1: Circuit Generation, Analysis and Design 
Energies 2012, 5(11), 4590-4623; doi:10.3390/en5114590
Received: 6 August 2012 / Revised: 21 October 2012 / Accepted: 23 October 2012 / Published: 14 November 2012
Cited by 10 | PDF Full-text (1014 KB) | HTML Full-text | XML Full-text
Abstract
A novel asymmetrical interleaved dc/dc switching converters family intended for photovoltaic and fuel cell applications is presented in this paper. The main requirements on such applications are small ripples in the generator and load, as well as high voltage conversion ratio. Therefore, [...] Read more.
A novel asymmetrical interleaved dc/dc switching converters family intended for photovoltaic and fuel cell applications is presented in this paper. The main requirements on such applications are small ripples in the generator and load, as well as high voltage conversion ratio. Therefore, interleaved structures and voltage multiplier cells have been asymmetrically combined to generate new converters, which inherently operate indiscontinuous conduction mode. The novel family is derived from boost, buck-boost and flyback-based structures. This converter family is analyzed to obtain the design equations and synthesize a design process based on the typical requirements of photovoltaic and fuel cell applications. Finally, the experimental results validate the characteristics and usefulness of the asymmetrical interleaved converter family.  Full article
Open AccessArticle Novel Speed Bumps Design and Optimization for Vehicles' Energy Recovery in Smart Cities
Energies 2012, 5(11), 4624-4642; doi:10.3390/en5114624
Received: 13 August 2012 / Revised: 11 October 2012 / Accepted: 6 November 2012 / Published: 14 November 2012
Cited by 5 | PDF Full-text (891 KB) | HTML Full-text | XML Full-text
Abstract
Recently the technology development and increasing amounts of investment in renewables has led to a growing interest towards design and optimization of green energy systems. In this context, advanced Computational Intelligence (CI) techniques can be applied by engineers to several technical problems [...] Read more.
Recently the technology development and increasing amounts of investment in renewables has led to a growing interest towards design and optimization of green energy systems. In this context, advanced Computational Intelligence (CI) techniques can be applied by engineers to several technical problems in order to find out the best structure and to improve efficiency in energy recovery. This research promises to give new impulse to using innovative unconventional renewable sources and to develop the so-called Energy Harvesting Devices (EHDs). In this paper, the optimization of a Tubular Permanent Magnet-Linear Generator for energy harvesting from vehicles to grid is presented. The optimization process is developed by means of hybrid evolutionary algorithms to reach the best overall system efficiency and the impact on the environment and transportation systems. Finally, an experimental validation of the designed EHD prototype is presented. Full article
(This article belongs to the Special Issue Vehicle to Grid)
Open AccessArticle Development of a Terminal Control System with Variable Minimum Airflow Rate
Energies 2012, 5(11), 4643-4664; doi:10.3390/en5114643
Received: 12 June 2012 / Revised: 9 October 2012 / Accepted: 13 November 2012 / Published: 15 November 2012
Cited by 5 | PDF Full-text (763 KB) | HTML Full-text | XML Full-text
Abstract
A constant minimum airflow rate is used in conventional Single Duct Variable Air Volume Terminal Box control sequences. This control sequence can cause occupant discomfort or use excessive energy under partial load conditions. If the minimum airflow rate is higher than required; [...] Read more.
A constant minimum airflow rate is used in conventional Single Duct Variable Air Volume Terminal Box control sequences. This control sequence can cause occupant discomfort or use excessive energy under partial load conditions. If the minimum airflow rate is higher than required; terminal boxes will have significantly more simultaneous heating and cooling; and AHUs will consume more fan power. Buildings will have indoor air quality problems if the minimum airflow rate is less than required. Many engineers and researchers have investigated advanced variable air volume terminal box control algorithms without a system retrofit for thermal comfort; indoor air quality and energy savings. In this study a developed control system with variable minimum airflow rate for Single Duct Variable Air Volume Terminal Boxes was applied and validated using an actual building and evaluated for comfort; indoor air quality and energy consumption. The energy consumption and thermal performance of terminal boxes using the conventional and proposed control algorithms were compared. Full article
(This article belongs to the Special Issue Energy Efficient Buildings and Green Buildings)
Open AccessArticle A PEV Charging Service Model for Smart Grids
Energies 2012, 5(11), 4665-4682; doi:10.3390/en5114665
Received: 6 September 2012 / Revised: 25 October 2012 / Accepted: 6 November 2012 / Published: 16 November 2012
Cited by 10 | PDF Full-text (781 KB) | HTML Full-text | XML Full-text
Abstract
Plug-in Electric Vehicles (PEVs) are envisioned to be more popular during the next decade as part of Smart Grid implementations. Charging multiple PEVs at the same time within a power distribution area constitutes a major challenge for energy service providers. This paper [...] Read more.
Plug-in Electric Vehicles (PEVs) are envisioned to be more popular during the next decade as part of Smart Grid implementations. Charging multiple PEVs at the same time within a power distribution area constitutes a major challenge for energy service providers. This paper discusses a priority-based approach for charging PEVs in a Smart Grid environment. In this work, ideas from the communication network paradigm are being utilized and tailored toward achieving the desired objective of monitoring and controlling PEVs electric load in Smart Grid. A detailed example is given to show how uncontrolled penetration of PEVs can impact distribution transformer reliability. The paper introduces the concept of Charging Quality of Service (CQoS) as a smart electric vehicle charging scheme and models it using a priority-controlled leaky bucket approach. The performance of such a model is investigated under the umbrella of a Smart Grid environment. Full article
(This article belongs to the Special Issue Smart Grid and the Future Electrical Network)
Open AccessArticle Structural Optimization Design of Horizontal-Axis Wind Turbine Blades Using a Particle Swarm Optimization Algorithm and Finite Element Method
Energies 2012, 5(11), 4683-4696; doi:10.3390/en5114683
Received: 24 September 2012 / Revised: 8 November 2012 / Accepted: 12 November 2012 / Published: 16 November 2012
Cited by 7 | PDF Full-text (1389 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents an optimization method for the structural design of horizontal-axis wind turbine (HAWT) blades based on the particle swarm optimization algorithm (PSO) combined with the finite element method (FEM). The main goal is to create an optimization tool and to [...] Read more.
This paper presents an optimization method for the structural design of horizontal-axis wind turbine (HAWT) blades based on the particle swarm optimization algorithm (PSO) combined with the finite element method (FEM). The main goal is to create an optimization tool and to demonstrate the potential improvements that could be brought to the structural design of HAWT blades. A multi-criteria constrained optimization design model pursued with respect to minimum mass of the blade is developed. The number and the location of layers in the spar cap and the positions of the shear webs are employed as the design variables, while the strain limit, blade/tower clearance limit and vibration limit are taken into account as the constraint conditions. The optimization of the design of a commercial 1.5 MW HAWT blade is carried out by combining the above method and design model under ultimate (extreme) flap-wise load conditions. The optimization results are described and compared with the original design. It shows that the method used in this study is efficient and produces improved designs. Full article
Open AccessArticle Combined Optimal Sizing and Control for a Hybrid Tracked Vehicle
Energies 2012, 5(11), 4697-4710; doi:10.3390/en5114697
Received: 26 July 2012 / Revised: 4 November 2012 / Accepted: 12 November 2012 / Published: 19 November 2012
Cited by 15 | PDF Full-text (568 KB) | HTML Full-text | XML Full-text
Abstract
The optimal sizing and control of a hybrid tracked vehicle is presented and solved in this paper. A driving schedule obtained from field tests is used to represent typical tracked vehicle operations. Dynamics of the diesel engine-permanent magnetic AC synchronous generator set, [...] Read more.
The optimal sizing and control of a hybrid tracked vehicle is presented and solved in this paper. A driving schedule obtained from field tests is used to represent typical tracked vehicle operations. Dynamics of the diesel engine-permanent magnetic AC synchronous generator set, the lithium-ion battery pack, and the power split between them are modeled and validated through experiments. Two coupled optimizations, one for the plant parameters, forming the outer optimization loop and one for the control strategy, forming the inner optimization loop, are used to achieve minimum fuel consumption under the selected driving schedule. The dynamic programming technique is applied to find the optimal controller in the inner loop while the component parameters are optimized iteratively in the outer loop. The results are analyzed, and the relationship between the key parameters is observed to keep the optimal sizing and control simultaneously. Full article
Open AccessArticle Day-Ahead Electricity Price Forecasting Using a Hybrid Principal Component Analysis Network
Energies 2012, 5(11), 4711-4725; doi:10.3390/en5114711
Received: 5 September 2012 / Accepted: 12 November 2012 / Published: 19 November 2012
Cited by 19 | PDF Full-text (708 KB) | HTML Full-text | XML Full-text
Abstract
Bidding competition is one of the main transaction approaches in a deregulated electricity market. Locational marginal prices (LMPs) resulting from bidding competition and system operation conditions indicate electricity values at a node or in an area. The LMP reveals important information for [...] Read more.
Bidding competition is one of the main transaction approaches in a deregulated electricity market. Locational marginal prices (LMPs) resulting from bidding competition and system operation conditions indicate electricity values at a node or in an area. The LMP reveals important information for market participants in developing their bidding strategies. Moreover, LMP is also a vital indicator for the Security Coordinator to perform market redispatch for congestion management. This paper presents a method using a principal component analysis (PCA) network cascaded with a multi-layer feedforward (MLF) network for forecasting LMPs in a day-ahead market. The PCA network extracts essential features from periodic information in the market. These features serve as inputs to the MLF network for forecasting LMPs. The historical LMPs in the PJM market are employed to test the proposed method. It is found that the proposed method is capable of forecasting day-ahead LMP values efficiently. Full article
(This article belongs to the Special Issue Hybrid Advanced Techniques for Forecasting in Energy Sector)
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Open AccessArticle Concept Development of Optimal Mine Site Energy Supply
Energies 2012, 5(11), 4726-4745; doi:10.3390/en5114726
Received: 13 August 2012 / Revised: 23 October 2012 / Accepted: 7 November 2012 / Published: 19 November 2012
Cited by 1 | PDF Full-text (521 KB) | HTML Full-text | XML Full-text
Abstract
This paper reports on early work and concept development for Optimal Mine Site Energy Supply, where the specific energy supply requirements and constraints for mineral production operations are considered against methodologies that have been applied for other sectors and in other energy [...] Read more.
This paper reports on early work and concept development for Optimal Mine Site Energy Supply, where the specific energy supply requirements and constraints for mineral production operations are considered against methodologies that have been applied for other sectors and in other energy policy regimes. The primary motivation for this research is to help ensure that Canadian mineral producers will achieve reduced production costs through improvements in the efficiency with which they consume energy resources. Heat has not yet been considered for the mining sector in an integrated manner, which makes polygeneration of great interest. The methodology that optimizes configuration of polygeneration systems for mine sites has not been reported before. The variety of mining circumstances, temporal variations in energy prices, institutional inertia, and conservatism in design for mines are some of the reasons for this. This paper reviews some aspects of precedent energy management practice in mineral operations, which highlights energy challenges characteristic of the sector and sets out the initial formulation of optimal mine site energy supply. The review indicates the additional benefits of energy supply systems for mine sites that concurrently meet all utilities. Full article
Open AccessArticle Optimization of Key Factors Affecting Methane Production from Acidic Effluent Coming from the Sugarcane Juice Hydrogen Fermentation Process
Energies 2012, 5(11), 4746-4757; doi:10.3390/en5114746
Received: 27 August 2012 / Revised: 18 October 2012 / Accepted: 8 November 2012 / Published: 19 November 2012
Cited by 6 | PDF Full-text (997 KB) | HTML Full-text | XML Full-text
Abstract
Response surface methodology with a central composite design was applied to optimize the key factors affecting methane production from the acidic effluent coming from the sugarcane juice hydrogen fermentation process. The parameters studied were substrate concentration, ratio of NaHCO3 to substrate concentration and initial pH. The experimental results showed that substrate concentration and initial pH had significant individual (p < 0.05) effect on methane yield (MY). However, there was no interactive effect between these variables (p > 0.05). The maximum MY of 367 mL CH4/g-volatile solid (VS)added was obtained at the optimum conditions of 13,823 mg-COD/L, an NaHCO3 to substrate concentration ratio of 3.09 and an initial pH of 7.07. Under the optimum conditions, MY was enhanced 4.4-fold in comparison to raw effluent. Full article
Open AccessArticle Proportional-Resonant Control of Doubly-Fed Induction Generator Wind Turbines for Low-Voltage Ride-Through Enhancement
Energies 2012, 5(11), 4758-4778; doi:10.3390/en5114758
Received: 6 September 2012 / Revised: 5 November 2012 / Accepted: 5 November 2012 / Published: 19 November 2012
Cited by 9 | PDF Full-text (2031 KB) | HTML Full-text | XML Full-text
Abstract
A novel control strategy is proposed in this paper for the rotor side converter (RSC) of doubly-fed induction generator (DFIG)-based wind power generation systems. It is supposed to enhance the low-voltage ride-through (LVRT) capability of DFIGs during great-level grid voltage dips. The [...] Read more.
A novel control strategy is proposed in this paper for the rotor side converter (RSC) of doubly-fed induction generator (DFIG)-based wind power generation systems. It is supposed to enhance the low-voltage ride-through (LVRT) capability of DFIGs during great-level grid voltage dips. The strategy consists of a proportional-resonant (PR) controller and auxiliary PR controllers. The auxiliary controllers compensate the output voltage of the RSC in case of grid faults, thus limiting the rotor inrush current of DFIG and meeting the requirements of LVRT. Sequential-component decompositions of current are not required in the control system to improve the response of system. Since the resonant compensator is a double-side integrator, the auxiliary controllers can be simplified through coordinate transformation. The feasibility of the control strategy is validated by simulation on a 1.5 MW wind-turbine driven DFIG system. The impact of the RSC converter voltage rating on the LVRT capability of DFIG is investigated. Meanwhile, the influence of angular frequency detection and control parameters are also discussed. Compared with traditional vector control schemes based on PI current controllers, the presented control strategy effectively suppress rotor current and reduce oscillations of DFIG power and torque under grid faults. Full article
Open AccessArticle Non Breaking Wave Forces at the Front Face of Seawave Slotcone Generators
Energies 2012, 5(11), 4779-4803; doi:10.3390/en5114779
Received: 17 September 2012 / Revised: 1 November 2012 / Accepted: 16 November 2012 / Published: 19 November 2012
Cited by 15 | PDF Full-text (1351 KB) | HTML Full-text | XML Full-text
Abstract
The Seawave Slotcone Generator (WAVEnergy SAS, 2003) is a wave energy converter based on the overtopping principle. Although it has been effectively researched during the last decade, no design tool has been supplied to estimate the hydrodynamic loads the waves exert on [...] Read more.
The Seawave Slotcone Generator (WAVEnergy SAS, 2003) is a wave energy converter based on the overtopping principle. Although it has been effectively researched during the last decade, no design tool has been supplied to estimate the hydrodynamic loads the waves exert on its front face. In this article a set of well reliable 3D experiments has been re-analyzed, in order to get indications on possible calculation methods. It is shown that the Japanese design tools for monolithic sea dikes may be reasonably adapted to the present case. Finally a new approach is presented, which is based on the so called momentum flux principle; the resulting predictive equation fits the experimental data remarkably well. Full article
(This article belongs to the Special Issue Energy from the Ocean - Wave and Tidal Energy)
Open AccessArticle Optimal Bidding Strategies for Wind Power Producers in the Day-ahead Electricity Market
Energies 2012, 5(11), 4804-4823; doi:10.3390/en5114804
Received: 19 September 2012 / Revised: 13 November 2012 / Accepted: 13 November 2012 / Published: 20 November 2012
Cited by 5 | PDF Full-text (322 KB) | HTML Full-text | XML Full-text
Abstract
Wind Power Producers (WPPs) seek to maximize profit and minimize the imbalance costs when bidding into the day-ahead market, but uncertainties in the hourly available wind and forecasting errors make the bidding risky. This paper assumes that hourly wind power output given [...] Read more.
Wind Power Producers (WPPs) seek to maximize profit and minimize the imbalance costs when bidding into the day-ahead market, but uncertainties in the hourly available wind and forecasting errors make the bidding risky. This paper assumes that hourly wind power output given by the forecast follows a normal distribution, and proposes three different bidding strategies, i.e., the expected profit-maximization strategy (EPS), the chance-constrained programming-based strategy (CPS) and the multi-objective bidding strategy (ECPS). Analytical solutions under the three strategies are obtained. Comparisons among the three strategies are conducted on a hypothetical wind farm which follows the Spanish market rules. Results show that bid under the EPS is highly dependent on market clearing price, imbalance prices, and also the mean value and standard deviation of wind forecast, and that bid under the CPS is largely driven by risk parameters and the mean value and standard deviation of the wind forecast. The ECPS combining both EPS and CPS tends to choose a compromise bid. Furthermore, the ECPS can effectively control the tradeoff between expected profit and target profit for WPPs operating in volatile electricity markets. Full article
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Open AccessArticle Distributed Semantic Architecture for Smart Grids 
Energies 2012, 5(11), 4824-4843; doi:10.3390/en5114824
Received: 9 October 2012 / Revised: 1 November 2012 / Accepted: 14 November 2012 / Published: 20 November 2012
Cited by 6 | PDF Full-text (672 KB) | HTML Full-text | XML Full-text
Abstract
The smart grid revolution demands a huge effort in redesigning and enhancing current power networks, as well as integrating emerging scenarios such as distributed generation, renewable energies or the electric vehicle. This novel situation will cause a huge flood of data that [...] Read more.
The smart grid revolution demands a huge effort in redesigning and enhancing current power networks, as well as integrating emerging scenarios such as distributed generation, renewable energies or the electric vehicle. This novel situation will cause a huge flood of data that can only be handled, processed and exploited in real-time with the help of cutting-edge ICT (Information and Communication Technologies). We present here a new architecture that, contrary to the previous centralised and static model, distributes the intelligence all over the grid by means of individual intelligent nodes controlling a number of electric assets. The nodes own a profile of the standard smart grid ontology stored in the knowledge base with the inferred information about their environment in RDF triples. Since the system does not have a central registry or a service directory, the connectivity emerges from the view of the world semantically encoded by each individual intelligent node (i.e., profile + inferred information). We have described a use-case both with and without real-time requirements to illustrate and validate this novel approach. Full article
(This article belongs to the Special Issue Smart Grid and the Future Electrical Network)
Open AccessArticle An Industrial System Powered by Wind and Coal for Aluminum Production: A Case Study of Technical Demonstration and Economic Feasibility
Energies 2012, 5(11), 4844-4869; doi:10.3390/en5114844
Received: 8 October 2012 / Revised: 31 October 2012 / Accepted: 7 November 2012 / Published: 21 November 2012
Cited by 4 | PDF Full-text (1481 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a case study of an isolated industrial power system for aluminum production. The novel concept is that the cost of aluminum electrolysis can be significantly reduced by innovative application of hybrid systems incorporating wind energy and low-grade coal. In [...] Read more.
This paper presents a case study of an isolated industrial power system for aluminum production. The novel concept is that the cost of aluminum electrolysis can be significantly reduced by innovative application of hybrid systems incorporating wind energy and low-grade coal. In addition, the low-grade coal, which sale is not profitable in the market, can be locally consumed by the isolated power system. The power system thus fully utilizes the local resources in an effective and economic manner. However, several technical and economic issues are still of concern because the industrial system is isolated from the state grid. This paper hence discusses these issues and demonstrates the feasibility of such a hybrid power system from the technical and economic perspectives. Full article
Open AccessArticle Sustainability Impact Assessment on the Production and Use of Different Wood and Fossil Fuels Employed for Energy Production in North Karelia, Finland
Energies 2012, 5(11), 4870-4891; doi:10.3390/en5114870
Received: 6 September 2012 / Revised: 2 November 2012 / Accepted: 13 November 2012 / Published: 21 November 2012
Cited by 12 | PDF Full-text (605 KB) | HTML Full-text | XML Full-text
Abstract
The utilization rate of woody biomass in eastern Finland is high and expected to increase further in the near future as set out in several regional, national and European policies and strategies. The aim of this study was to assess the sustainability [...] Read more.
The utilization rate of woody biomass in eastern Finland is high and expected to increase further in the near future as set out in several regional, national and European policies and strategies. The aim of this study was to assess the sustainability impacts of changes in fuel consumption patterns. We investigated fossil and woody biomass-based energy production chains in the region of North Karelia, focusing on some economic, environmental and social indicators. Indicators were selected based on stakeholder preferences and evaluated using the Tool for Sustainability Impact Assessment (ToSIA). The analysis was based on representative values from National Forest Inventory data, scientific publications, national and regional statistics, databases, published policy targets and expert opinion. From the results it became evident that shifting from fossil to wood-based energy production implies some trade-offs. Replacing oil with woody biomass in energy production would increase the local value added remaining in the region, create employment opportunities and would reduce total GHG emissions. However, firewood, wood chips from small-diameter trees from early thinning and wood pellets have high production costs. Moreover, large greenhouse gas emission resulted from wood pellet production. The case study generated valuable reference data for future sustainability assessments and demonstrated the usefulness of ToSIA as a tool presenting existing knowledge on sustainability impacts of alternative energy supply chains to inform decision making. Full article
(This article belongs to the Special Issue Wood to Energy)

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