Utilization Of Renewable Energy Resources Research Articles

Modelling of two-phase closed thermosyphon based on SINDA/FLUINT

Two-phase closed thermosyphons (TPCTs) are simple and efficient heat exchangers. They have been explored for use in the renewable energy resource utilization marker and low grade thermal energy heat recovery systems. A transient simulation model for a TPCT was established by SINDA/FLUINT with low global warming potential Freon R245fa as working fluid. The TPCT was manufactured from a 40 mm inner diameter (Di), 3 m long smooth copper tube with a wall thickness of 2 mm. It consists of the evaporator, adiabatic and condenser sections with 1 m long for each section. The evaporator section was immersed in a water bath and the condenser section was cooled by recycled water. The effects of water bath temperature Tb and inlet temperature of cooling water Tcw,i were investigated by experimental and simulation methods. The results show the heat transfer rate Q and overall heat transfer coefficient U increase with the increase of Tb, and the decrease of Tcw,i. Good agreement between experimental and simulation results confirms the model is accurate and reliable. The influence of filling ratio (FR) and Di on the performance of TPCT was also investigated. The optimum FR for Di of 30 mm, 40 mm and 50 mm are 15%, 15% and 25% respectively. Moreover performances of 60–150 m long TPCTs were investigated based on the developed model.

Can spatial planning really mitigate carbon dioxide emissions in urban areas? A case study in Taipei, Taiwan

Spatial planning plays an increasingly significant role in climate change mitigation by providing energy efficient settlements and promoting the utilization of renewable energy resources. However, the effect of urban spatial planning on spatial pattern of carbon dioxide emissions in cities is rarely discussed. The relationships between the changes in urban zoning plans and carbon dioxide emissions of major economic sectors has yet to be investigated on a scale smaller than an entire city. Using the Taipei metropolitan area as a case study, this study hypothesizes that: (1) carbon dioxide emissions have a spatial dimension within the city due mainly to the heterogeneous nature of land use activities and urbanization, and (2) changes in spatial planning can influence the urban form, and consequentially affect carbon dioxide emissions through changes in traffic demand and energy consumption. A downscaling analysis approach was used to estimate carbon dioxide emissions of different sectors for each administrative district in the Taipei metropolitan area. The analytical results reveal that the total carbon dioxide emissions of the four sectors in the Taipei metropolitan area increased with the increases in the growth of urban planned zones during the period 1981–2011.The carbon dioxide emission increases were correlated with the distribution of land uses in each administrative district. A negative correlation was found between the population density and the per-capita carbon dioxide emissions in the transportation sector. The compact development and planning of urban transit systems are believed to be the source of decreasing per-capita carbon dioxide emissions. While many studies have emphasized that spatial planning is important addressing climate change, this work demonstrates understanding the historic links between spatial planning and carbon dioxide is equally valuable.

Experimental investigation of a two-phase closed thermosyphon charged with hydrocarbon and Freon refrigerants

Two-phase closed thermosyphons (TPCTs) are simple, efficient, and low cost heat exchangers. They have been explored for use in the renewable energy resource utilization marker and low grade thermal energy heat recovery systems. Freon R134a has been extensively used in refrigeration systems and researched as a working fluid of TPCTs; however; it has high global warming potential and operating pressure. In this paper, an experimental investigation of the performance of TPCTs charged with eight working fluids: R134a, R601, R245fa, R600a, R1234ze, R152a, R245fa/R152a, and R601/R245fa have been carried out. The experimental results showed that R245fa/R152a offered the best performance in maximum heat transfer rate. R134a outperformed the other pure working fluids, while R600a and R1234ze had close performances to that of R134a. R245fa showed marginal improvement at higher operating temperatures. The predictions of six evaporation heat transfer coefficients (HTCs) correlations, including Imura, Shiraishi, Labuntsov, Kutateladze, Cooper, and Rohsenow were compared with the experimental results. In the five constant coefficients and powers correlations, the Shiraishi and Cooper correlations had superior accuracy. The coefficients and powers of the Rohsenow correlations fitted based on the experimental data, while they had the best accuracy. Nusselt and Hashimoto-Kaminaga correlations were chosen to predict the condensation HTCs. Both of them tend to over-predict the condensation HTCs in low heat fluxes while under-predicting in high heat fluxes. The experimental results had greater agreement with Hashimoto and Kaminaga correlations.

Optimized Hybrid Wind-Diesel Energy System with Feasibility Analysis

The enormous percentage of people in the world; particularly in the developing countries; are living mostly in decentralized, rural and remote areas, those are geographically secluded from the main grid connection. The power distribution and continuous fuel transportation to generate electricity for these areas pretenses a very big challenge. By proper utilization of renewable energy resources in off grid hybrid energy systems will be an efficient solution of this crisis. Moreover, the high cost of renewable energy systems has led to its slow adoption in many developing countries. Hence, it is very important to find an appropriate size of system in order to reduce the energy cost and excess electricity generation as well as to maximize the available resources. Therefore, a hybrid energy system has been designed and simulated to support a small community considering an average load demand of 85 kWh/d with a peak load of 8.7 kW. The simulation and optimization of the system have been performed by the HOMER software using real time field data of solar radiation, wind speed and biomass of that particular area. The simulation results confirm that the system is suitably feasible with respect to the net present cost (NPC) and CO2 emission reduction purpose. The simulation results also confirm that the NPC and CO2 emission can be reduced about 32.45% and 29 tons per year respectively compared to the conventional power plants. The NPC of the optimized system has been found about USD $160,626 having per unit Cost of Energy (COE) about USD $0.431/kWh and the operating cost USD $10,779/yr.

Assessing and mapping energy biomass distribution using a UAV in Finland

ABSTRACTThe increasing need to reduce greenhouse gas emissions to slow down climate change requires more effective and versatile methods for producing energy. In Finland, common reed and forest biomass are used for energy production. There are efforts to increase the utilisation of renewable energy resources. The potential intensification of renewables utilisation may result in changes to the landscape's structure and functions. The objective of this study was to develop a method for energy biomass mapping in landscapes using high-resolution remote sensing data from an unmanned aerial vehicle (UAV). The images were obtained from UAVs in Ojalahti, Lipperi, Finland, and a point cloud was calculated from the overlapped images. Individual plants were automatically identified using object-oriented image processing. The size of the individual plants was measured from orthophotographs and the point cloud. It was possible to develop an accurate three-dimensional model of the biomass distribution within the landscape. The error in height measurements of common reed plants and forest trees was 0.044 m. The root-mean-square deviation in common reed biomass measurements using the UAV data obtained was 0.096 m3. The new method developed in this study could be used as a cost-effective solution for common reed biomass resources assessment. This would allow for the mobilisation of common reed biomass for sustainable energy production.

An Energy Policy Analysis and Proposed Remedial Actions to Reduce Energy Crises in Pakistan

Pakistan energy demand has grown exponentially over the last 2 decades. Reason behind increasing energy demand is excessive mobility of rural population to cities, rapid progression in industrial and transport sector, lack of policy making and implementation on the developed policies and improvements in living style. At present, Pakistan witness 5000-7000 MW power deficit in summer. To reduce the demand and supply gap, power plants across Pakistan are planned to be installed while some are under development phase. Power expansion plans cannot cope with the current energy shortfall since several years are required for them to get fully operational. Effective energy policy is the only key to address the existing shortfall. This paper discusses the initiatives that may be taken to reduce the power shortfall using energy efficiency and conservation, deployment of microgrids, utilization of renewable energy resources and effective research and development in energy sector. Since another most important issue evaluated in the research regarding the energy crises is energy efficiency and lack of compliance to government regulations for energy efficiency and conservation. Implementation on the policies developed for energy efficiencies and conservation has not been witnessed. Possible solutions on short term basis to lessen the energy crises have also been discussed in the paper.

Future of Renewable Resources in an Area Burdened by Brown Coal Mining

This contribution is focused on a possible utilization of renewable energy resources in the Podkrušnohoří region (Chmomutov, Most, Teplice, ústí nad Labem districts) in the northern part of the Czech Republic after the end of brown coal mining in 2055. Results of the research describe current share of renewable energy resources (solar, wind, water, biogas) in the model area, and a future energy potential in order to ensure sustainable development of an anthropogenically burdened region. Aim of this contribution is to determine, which renewable energy resources would be the most suitable for energy production after the end of brown coal mining. It also describes current and possible use of geothermal power as there are registered heat flow anomalies in the area.

Techno‐economic analysis of a PV–wind–battery–diesel standalone power system in a remote area

The global acceptance of solar and wind resources for power generation has continued to increase due to the fluctuation of world oil and gas prices, recent advances in technology, high prices of fossil fuels, no direct greenhouse gas emission from solar and wind resources and government policies to support utilisation of renewable energy resources (RESs). In recent times, RESs have become a potential alternative to supply electricity to the rural communities where the extension of transmission and distribution lines is difficult due to technical and financial barriers. In view of this, this study deals with the optimisation of net present cost (NPC), fuel cost, operation cost and cost of energy (COE) of the hybrid system which consists of photovoltaic (PV), wind turbine generator (WTG), diesel generator and battery storage system. A hybrid power system is designed in this research work to serve a remote community. The optimisation of the key performance indicators of the proposed hybrid power system is done by using the hybrid optimisation model for electric renewable (HOMER). The results obtained from this research work are analysed to select the best options among the available configurations based on the lowest NPC and COE produced by each configuration. The simulation results from several case studies show that incorporation of PV and WTG have reduced the operating cost of the system.

Optimal scheduling of dispatchable distributed generation in smart environment with the aim of energy loss minimization

It is obvious that the high accurate information of network conditions in smart grids definitely leads to high efficient performance of the network. This paper discusses how much is the effect of smart grid compared to conventional networks to the daily energy loss minimization. In other words, the question of “is it worth to move towards the smart environment?” is discussed from only an aspect point of view in the paper. For this purpose, an optimal management of Dispatchable Distributed Generation (DDG) in smart grid with the aim of daily energy loss minimization is performed and fairly compared to DDG optimal management in conventional distribution networks. The effect of suboptimal performance of the system in conventional networks is economically analyzed. A 3-level load profile which is forecasted in advance is taken into account as the load profile of the conventional network. This load profile is investigated in 5 different scenarios from prediction points of view. On contrary, the load profile of the network in smart environment is considered as a 24-h load profile which is achieved using smart metering devices. To show how the smart grid impressively affects the network performance regards to conventional network, the DDGs are also programed in order to minimize the voltage deviation of the network. The economic analysis and yearly benefit of loss reduction are also conducted in both situations (smart grid and conventional network). In addition, the performances of the conventional network and smart grid are evaluated in two other phases i.e., in the presence of renewable energy resources and encountering with disturbances. The study is applied on 69-bus radial test system which is used in many previous studies. The results show the detrimental effects of suboptimal operation of the system on network performance in the case of conventional networks. Moreover, the impressive impacts of smart environment on energy loss reduction and voltage profile improvement in distribution systems can be concluded from the results. Furthermore, the study shows how the smart environment can be useful for utilization of renewable energy resources and managing the disturbances.

Numerical Investigation of the Performance of Pitching Airfoils at High Amplitudes

Recently, a renewed interest toward vertical-axis wind turbines has developed, due to the increasing need of a rational utilization of renewable energy resources. In vertical-axis wind turbines, each blade undergoes a wide variation of angle of attack during one rotation, with important dynamic stall phenomena. Neglecting wake-to-wake interactions and curvature effects, a pitching airfoil is a good representation of the flow experienced by the blades of a vertical-axis wind turbine. In the present work, the flow around an Eppler 387 airfoil in pure pitching is investigated, exploring a parametric space tailored to vertical-axis wind-turbine applications. In such a case, the angle of attack varies in the range , resulting in large-amplitude pitching oscillations. The Reynolds number, based on the freestream velocity and the chord length, is set to . In this sense, the present work differs from earlier studies, where typically the combined heaving and pitching or pure pitching for propulsion purposes have been considered, which are characterized by higher frequencies and smaller amplitudes and mainly positive angles of attack. In this paper, a detailed analysis of the force coefficients and how their evolution is affected by the dynamics of the flow structures generated during pitch-up and pitch-down of the airfoil is presented. Furthermore, it is shown that a modified Strouhal number, which takes into account both frequency and amplitude, is an appropriate metric for the performance of an airfoil in these conditions.

A Review of Solar-Powered Boat Development

Research in the application of renewable energy has intensified in recent years. The possibility of petroleum extinction in the future is forcing researchers to enhance the utilization of renewable energy resources as substitute for fossil fuel-based technologies in all fields. Ships as one of the most important transportation in the world also require diesel oil as fuel for main propulsion systems and for diesel generators which supply electrical needs. Solar energy has been considered as the most suitable renewable energy resources to substitute the role of fuel in the ships. In this paper, the latest research on the utilization of solar energy in the ship are presented and analyzed to provide information for the researchers who developed the technology of solar-powered boat

Real-Time Energy Imbalance Management Scheme for Electric Vehicles in the Smart Grid

Electric Vehicles (EVs) as the alternative of the current fossil fuels vehicles represent the most promising green approach to the electrification of a significant portion of the transportation sector. Taking the randomness of EV's charging/ discharging characteristics into consideration, a significant uncertainty will be added to the grid by the large penetration of EVs. Consequently, charging/ discharging management of EVs in presence of large scale intermittent Renewable Energy Resources (RERs) are considered as the most significant challenge for the future smart grid. In this context, a novel market-oriented energy imbalance management scheme is proposed for the seamless integration of EVs to the grid. The proposed scheme which, unlike previous works, utilizes the grid's operating characteristics model within the signaling game-theoretic approach for the successful operation of electicity market. Optimal decision strategies for both EV owners and utility are devised by capturing the conflicting economic interests of players together under load/generation uncertainities. The maximization of the profit expectation of each market player in the presence of independent multi-generation resources is considered. This facilitates both the customer and utility to derive their robust bidding strategies. The efficacy of the proposed approach in reducing peak loads while satisfying customers needs are demonstrated by simulating the various scenarios of different penetration levels of EVs to the grid. Results show that the proposed methodology can successfully alleviate the peaks caused by the mass adoption of EVs with the better utilization of RER.

Synthetic fault factor features under Weibull stochastic interference

Abstract Wind power is a rich, widespread and renewable energy, it is also one of the vitally important alternative energies. Wind power belongs to the renewable energy without pollution, and the power generation by wind can reduce harmful gas released from conventional power generation process with mineral fuel, and then decrease the development of greenhouse effect and acid rain. The wind power has been greatly developed in the global scope with maturing wind power techniques, and will maintain persistent growing. The development and utilization of renewable energy resources is the future development direction. In this paper, taking full account of the fluctuation and unpredictability of wind power, one will put forward two types of fault factor features extraction schemes, fault feature I: Factor coefficients and fault feature II: Factor scores, on the basis of these two schemes, one can realize accurate and reliable fault identification. The research in this paper has direct and practical significance for promoting the large-scale exploitation and utilization of wind energy. And the proposed fault factor features extraction schemes will contribute to the future construction of smart grid.

A Review of Considered Factors to Penetrate Renewable Energy Resources in Electrical Power System

<p>As an increasing of load demand, scarcity of fossil fuel and penetration of greenhouse gasses (GHG) effect, utilization of renewable energy resources (RER) such as wind, solar, biomass and tidal are rising drastically. Distributed generation (DG) is a technology giving opportunity to integrate RER into power system network. These integrations are needed optimal long term planning. Those planning, hopefully, can increase reliability of electrical power system network while saving environment from GHG with minimum infestation, operation and maintenance cost. The aim of this paper is reviewing factors should be consider when preparing, operating and evaluating electrical power system with integration of RER. By this planning, it is expected that its integration is effective and efficient in a lifetime of project. Finally, this review can help government, researcher, engineer and private sector to make policies to preparing hybrid power system-DGs. </p><p><strong>Keywords</strong>: <em>Penetration of renewable energy resources, electrical power system, long term planning, distributed generation, policies </em></p>

An Optimal Energy Management System for Islanded Microgrids Based on Multiperiod Artificial Bee Colony Combined With Markov Chain

The optimal operation programming of electrical systems through the minimization of the production cost and the market clearing price, as well as the better utilization of renewable energy resources, has attracted the attention of many researchers. To reach this aim, energy management systems (EMSs) have been studied in many research activities. Moreover, a demand response (DR) expands customer participation to power systems and results in a paradigm shift from conventional to interactive activities in power systems due to the progress of smart grid technology. Therefore, the modeling of a consumer characteristic in the DR is becoming a very important issue in these systems. The customer information as the registration and participation information of the DR is used to provide additional indexes for evaluating the customer response, such as consumer's information based on the offer priority, the DR magnitude, the duration, and the minimum cost of energy. In this paper, a multiperiod artificial bee colony optimization algorithm is implemented for economic dispatch considering generation, storage, and responsive load offers. The better performance of the proposed algorithm is shown in comparison with the modified conventional EMS, and its effectiveness is experimentally validated over a microgrid test bed. The obtained results show cost reduction (by around 30%), convergence speed increase, and the remarkable improvement of efficiency and accuracy under uncertain conditions. An artificial neural network combined with a Markov chain (ANN-MC) approach is used to predict nondispatchable power generation and load demand considering uncertainties. Furthermore, other capabilities such as extendibility, reliability, and flexibility are examined about the proposed approach.

Optimizing Gas Diffusion Electrode for Electrochemical Reduction of CO2 to CO

Over the past several decades the atmospheric CO2 levels have risen to levels that are now being associated with climate change, as well as the abnormal weather patterns (1) . To curb this rise and ultimately lower the atmospheric CO2 levels, multiple strategies are being considered, including carbon capture and sequestration, improvement of fuel efficiency of cars, the energy efficiency of buildings, and the increased utilization of renewable energy resources (2). Electrochemical reduction of CO2 into value-added products such as carbon monoxide (CO), formic acid, ethylene and ethanol may provide an additional option to not only reduce CO2 emissions but also to utilize excess, otherwise wasted energy from intermittent renewable sources. Furthermore, utilization of CO2 as a feedstock for chemical production may reduce global dependency on fossil fuels. Significant work is ongoing to improve the catalysts needed for electroreduction of CO2 to different products. With better catalysts becoming available mass transport limitations to and from the electrode surface need to be overcome for electroreduction of CO2 to become economically viable. Several factors, including elevated pressure, electrode modification and the use of non-aqueous electrolytes, have been studied to improve mass transport (3). Gas diffusion electrodes (GDEs) are utilized for a range of applications including fuel cells and electrolysis cells (4,5). A GDE consists of a carbon fiber substrate (CFS), a microporous layer (MPL), and a catalyst layer (CL). MPLs, typically composed of carbon powder and poly-tetrafluoroethylene (PTFE), can reduce the contact resistance between the CL and the CFS by forming a flat and strong interfacial layer, while at the same time forming a barrier for liquid water. In prior work, we developed a fully-automated air-brush-based catalyst layer deposition method to achieve a uniform catalyst layer, leading to increased current density and improved product selectivity in CO2 reduction (4). However, the effect of CFS and MPL composition in a GDE on CO2 reduction has not been studied extensively. To improve the CO2 electroreduction performance, we explored the effect of MPL and CFS composition on product selectivity and partial current density for the electroreduction of CO2 to CO. We varied PTFE amounts in the MPL from 5 to 50 wt.%, and characterized these electrodes in an electrolyzer with a flowing electrolyte. A 20 wt.% PTFE loading in the MPL exhibited the highest Faradaic efficiency and partial current density for CO. We also varied the thickness of the CFS while using an optimized MPL (20 wt.% PTFE) and tested these electrodes with two different feeds (100% CO2 and 50% CO2/50% N2 by volume). Better performance was observed with the thinner CFS (60-10%) than the thicker CFS (90-10% and 120-10%) while using the diluted CO2 feeds (Figure 1). The thinner CFS may have a higher gas permeability resulting in a higher maximum current density. Note that no significant difference in performance was observed performing the same CFS thickness study with a 100% CO2 feed. In summary, this paper will report on GDEs that have been optimized for the electroreduction of CO2, specifically leading to higher current densities and improved product selectivities, by varying the composition and thickness of some of its layers.

Development of Energy Management System for Micro-Grid with Photovoltaic and Battery system

Global environmental concerns and the ever increasing need of energy, coupled with steady progress in renewable energy technologies, are opening up new opportunities for utilization of renewable energy resources. Distributed electricity generation is a suitable option for sustainable development thanks to the load management benefits and the opportunity to provide electricity to remote areas. Solar energy being easy to harness, non-polluting and never ending is one of the best renewable energy sources for electricity generation in present and future time. Due to the random and intermittent nature of solar source, PV plants require the adoption of an energy storage and management system to compensate fluctuations and to meet the energy demand during night hours. This paper presents an efficient, economic and technical model for the design of a MPPT based grid connected PV with battery storage and management system. This system satisfies the energy demand through the PV based battery energy storage system. The aim is to present PV-BES system design and management strategy to maximize the system performance and economic profitability. PV-BES (photovoltaic based battery energy storage) system is operated in different modes to verify the system feasibility. In case of excess energy (mode 1), Li-ion batteries are charged using CC-CV mechanism effectively controlled by fuzzy logic based PID control system whereas during the time of insufficient power from PV system (mode 2), batteries are used as backup to compensate the power shortage at load and likewise other modes for different scenarios. This operational mode change in PV-BES system is implemented by State flow chart technique based on SOC, DC bus voltages and solar Irradiance. Performance of the proposed PV-BES system is verified by some simulations study. Simulation results showed that proposed system can overcome the disturbance of external environmental changes, and controls the energy flow in efficient and economical way.

Chance-constrained two-stage fractional optimization for planning regional energy systems in British Columbia, Canada

Abstract In this study, a chance-constrained two-stage fractional optimization (CTFO) method is proposed for planning regional energy systems in the province of British Columbia, Canada. Through simultaneously integrating two-stage stochastic programming (TSP), chance-constrained programming (CCP), and mixed-integer linear programming (MILP) techniques into a linear fractional programming (LFP) framework, CTFO can effectively tackle multiobjective and capacity-expansion issues, as well as uncertainties described as probability distributions in the constraints and objectives. Based on the developed CTFO method, a chance-constrained two-stage fractional regional energy model (CTFO-REM) is developed in this study for supporting energy management in the province of British Columbia. Conflicts between environmental protection that maximizes the renewable energy resource utilization and economic development that minimizes the system cost can be effectively addressed through the CTFO-REM model without setting a factor for each objective. The results also indicate that the CTFO-REM model can facilitate dynamic analysis of the interactions among efficiency, policy scenarios, economic cost, and system reliability.

Perspectives of Feedstock Supply for Biomass-Based Energy Plant Development in India: Views from an Expert Survey

Utilization of renewable energy resources is imperative due to energy access, energy security, and energy sustainability coupled with the rising environmental concern. India is one of the largest land mass countries in the world and amply bestowed with biomass resources. Investigations on biomass supply potential, socio-economic challenges, local people attitudes, current bioenergy markets, and technologies are prerequisite while seeking to develop sustainable energy plants. The study aimed to assess expert attitudes on wood-based energy development in India. This assessment was based on the opinions of Indian Forest Service (IFS) officers who are involved in managing wood-based biomass resources in different parts of the country. The study gave emphasis to the advantages, problems, and directions of the biomass based energy development in the country. The results showed that the development of biomass-based energy plants involves a number of challenges both locally and nationally. In addition, the study also highlighted the possible benefits of developing biomass based energy plants at local and national levels. The outcomes of this study provide useful information to the policy decision makers, energy entrepreneurs, and other stakeholders in the development of biomass based energy in India.

Evaluation on External Economies of Renewable Energy Resource Utilization: Taken Wind Power Engineering Project as Example

Different wind power projects have different external economics level, the practical evaluation on which can provide reference for wind power projects selection and qualify the role of completed projects. In this paper, the external economies of wind power engineering projects were evaluated by employing VIKOR method. The basic theory of VIKOR method was firstly introduced, and then the empirical evaluation was performed. After the evaluation index system was built from environmental, social and economic aspects, the external economies of three selected wind power engineering projects in Hebei province were studied. The evaluation result shows the external economies of wind power project #3 are the best one. The application of VIKOR method in external economies evaluation of wind power project is effective and feasible.