Utilization Of Renewable Energy Resources Research Articles

The Assessment of Off-Grid Photovoltaic (PV) Systems for Rural Electrification in Indonesia

There are many rural areas in Indonesia without electricity, especially in remote islands which are challenging to access. The limited access to electricity inhibits people in rural areas to increase their welfare and quality of life. Identifying the urge for electricity access in remote areas and for increasing the utilization of renewable energy resources in Indonesia, the off-grid photovoltaic (PV) systems can be the solution. The paper aims to assess the off-grid PV systems for rural electrification in Indonesia. The Levelized cost of energy (LCOE) is conducted to assess the cost-effectiveness of the off-grid PV systems compared to other rural electrification solutions in Indonesia, such as diesel and micro-hydro. It results that LCOE of the PV battery has the highest LCOE with 0.30 US$/kWh. Another off-grid PV configuration: PV battery diesel (hybrid system) has LCOE ranging from 0.19 to 0.22 US$/kWh. This hybrid system can compete with the LCOE of diesel generator (0.17 – 0.24 US$/kWh). The range of LCOE reflects the variation of retail diesel prices in remote areas. The micro-hydro power plant has the lowest LCOE, 0.16 US$/kWh. However, this solution is only reliable in the areas that have stable water flow rate with different elevation. In this case, the off-grid PV systems are more reliable to generate electricity in remote areas because the average daily solar irradiation is 4.8 kWh/m2/day across Indonesia. Additionally, the trend of cost reduction in PV systems and the improvement in PV technologies can be game-changing that make off-grid PV systems more competitive compared to other solutions. Then, the paper analyses the fundamental issues regarding the off-grid PV systems application and it also recommends the policies that can be taken by the Government of Indonesia and the local government to provide sustainable rural electrification based on the off-grid PV systems.

Policy Trends on Renewable Energy for Decentralised Electrification as a Catalyst for Achieving Goal Seven of the Sustainable Development Goals in sub-Saharan Africa.

The 2030 Agenda for Sustainable Development emphasises the quintessential role that energy plays in achieving the global sustainable development objectives. Renewable energy is vital to achieving many of the seventeen targets of Sustainable Development Goals. These, among others, include the ending of poverty; the ensuring of healthy lives and well-being for all; ensuring inclusive and equitable quality education for all; the promotion of sustained, inclusive and sustainable economic growth; and taking urgent action on combating climate changes and its impacts (goals 1, 3, 4, 8, and 13). With its high rate of lack of access to electricity, national governments in sub-Saharan Africa are, through energy policies, encouraging the utilisation of renewable energy resources to improve electricity access in the region. This paper examines the current trends in policy framework for energy in light of the feasibility and promotion of ensuring access to affordable, reliable, sustainable and modern energy to the rural population in Ghana. This paper argues that much of the emphases in promoting rural electrification in the policy framework should be put on educating the rural population on the benefits of having non-connected grid access to electricity. This will encourage its acceptance in those communities where the usefulness and significance of decentralised electrification from renewable energy sources are highlighted the most.

Transient 3D

This article describes the limitations and the environmental effects of fossil fuels have provided the drive to create replacement strategies, such as the utilization of renewable energy resources. Solar energy and related technologies are also among fast-growing renewable resources and technologies. Despite different research on solar technologies, an extensive research on the effects of different parts of the collector, such as an absorber, glass cover, and the air gap has not conducted in the warm climate in the Middle East. This article focuses on an unsteady and three-dimensional simulation of a flat plate solar collector considering Discrete Transfer Radiation Model (DTRM). The parameters effecting on efficiency of collector such as the absorber material, tilt angle of the collector and effect of double glazing are analyzed. The result of the numerical analysis shows parameters effecting on collector efficiency, and double-glazed glass.

Pemanfaatan Bagas sebagai Bahan Baku Pembuatan Bioetanol dengan Metode Pretreatment Alkali

Indonesia being an agricultural country produces a large amount of cellulosic biomass such as sugarcane bagasse. This provides a low-cost feedstock for fermentative production of a wide range of fuels, economic, renewable and environmentally friendly. With utilization of renewable energy resource a crisis of energy could be solved. Sugarcane bagasse contains lignocellulose which can be broken down into glucose and produce ethanol by fermentation process. This study describes the pretreatment of sugarcane bagasse with different method of alkaline pretreatment. Sugarcane bagasse was pretreated with heating process (80oC) and without heating process (25oC) and different concentration of Alkaline (NaOH). This study also descibes the influence of fermentation time to refractive index, volume of bioethanol and % Ethanol. The alkaline pretreatment method was able to effectively increase enzymatic disgetibility of sugarcane bagasse cellulose. Based on the best result, the best condition for pretreatment to produce highest cellulose (50,71 %) was pretreatment with heating process and using NaOH 3 N. The highest refractive index was 1,3391 from 5 days fermentation. The highest volume of bioethanol was 16 ml from 7 days fermentation. The highest % etanol was 56 based on standard plot analysis method and 47,708 based on GC analysis method.

Planning of Distribution System with High Penetration Level for Distributed Generation in Smart Grid

Nowadays, the utilization of renewable energy resources in distribution systems (DSs) has been rapidly increased. Since distribution generation (DG) use renewable resources (i.e., biomass, wind and solar) are emerging as proper solutions for electricity generation. Regarding the tremendous deployment of DG, common distribution networks are undergoing a transition to DSs, and the common planning methods have become traditional in the high penetration level. Indeed, in conformity with the voltage violation challenge of these resources, this problem must be dealt with too. So, due to the high penetration of DG resources and nonlinear nature of most industrial loads, the planning of DG installation has become an important issue in power systems. The goal of this paper is to determine the planning of DG in distribution systems through smart grid to minimize losses and control grid factors. In this regard, the present work intending to propose a suitable method for the planning of DSs, the key properties of DS planning problem are evaluated from the various aspects, such as the allocation of DGs, and planning, and high-level uncertainties. Also depending on these analyses, this universal literature review addressed the updated study associated with DS planning. In this work, an operational design has been prepared for a higher performance of the power distribution system in the presence of DG. Artificial neural network (ANN) has been used as a method for voltage monitoring and generation output optimization. The findings of the study show that the proposed method can be utilized as a technique to improve the process of the distribution system under various penetration levels and in the presence of DG. Also, the findings revealed that the optimal use of ANN method leads to more controllable and apparent DS.

Energy and Exergy Analysis of Ocean Compressed Air Energy Storage Concepts

Optimal utilization of renewable energy resources needs energy storage capability in integration with the electric grid. Ocean compressed air energy storage (OCAES) can provide promising large-scale energy storage. In OCAES, energy is stored in the form of compressed air under the ocean. Underwater energy storage results in a constant-pressure storage system which has potential to show high efficiency compared to constant-volume energy storage. Various OCAES concepts, namely, diabatic, adiabatic, and isothermal OCAES, are possible based on the handling of heat in the system. These OCAES concepts are assessed using energy and exergy analysis in this paper. Roundtrip efficiency of liquid piston based OCAES is also investigated using an experimental liquid piston compressor. Further, the potential of improved efficiency of liquid piston based OCAES with use of various heat transfer enhancement techniques is investigated. Results show that adiabatic OCAES shows improved efficiency over diabatic OCAES by storing thermal exergy in thermal energy storage and isothermal OCAES shows significantly higher efficiency over adiabatic and diabatic OCAES. Liquid piston based OCAES is estimated to show roundtrip efficiency of about 45% and use of heat transfer enhancement in liquid piston has potential to improve roundtrip efficiency of liquid piston based OCAES up to 62%.

A chance-constrained two-stage stochastic programming model for reliable microgrid operations under power demand uncertainty

Abstract In this study, we present a scalable quantitative modeling framework to evaluate the impacts of variability in renewable resources (e.g., solar energy) in the microgrid operation. The problem is formulated as a chance-constrained two-stage stochastic programming model. We use three different policies to ensure that the utilization of renewable energy is high in microgrid operations. More specifically, the first policy enforces a certain percentage of renewable energy utilization from the overall time period while the second and third policies enforce renewable energy utilization for specific hours and every operating hours, respectively. The proposed optimization model is solved using a combined Sample Average Approximation algorithm. Computational results indicate that policy three is more restrictive than the other two policies; thus, we observe high utilization of renewable energy resources in the microgrid operation under this policy. Further, we observe potential benefits of having solar panels under different fuel based generation (FBG) or distributed energy sources (DES) units on fulfilling the required energy demand during a power outage. Finally, the proposed model provides an optimal dispatch of available resources (e.g., renewable energy, DES, FBG units) in such a way that the overall microgrid operational cost is minimized.

Study on Correlativity of Influencing Factors of Tunnel and Solar Chimney Ventilation Composite System

The two types of passive system, the tunnel ventilation and the solar chimney ventilation, are combined to adjust the indoor thermal environment and it can fully realize the optimized utilization of renewable energy resources. In this paper, through the establishment of tunnel and solar chimney ventilation composite system model, study on the correlativity of influencing factors of the tunnel length, the ratio of tunnel air inlet to solar chimney area, the height of the solar chimney and soil type etc. The results show that the maximum value of soil type is the highest, when reaching 2.90, indicating the greatest influence on indoor temperature. When optimizing the design of ventilation composite system, the adaptability of local soil to the system should be given priority. If the soil type cannot meet the demand of the heat exchange of the tunnel ventilation system, the method of selecting the appropriate diameter and increase the length of tunnel can be achieved. When the tunnel length is 3 times the length of the room and the soil is marble, the air temperature will decrease by 4 degrees after the cooling of the tunnel.

Performance simulation of a grid connected photovoltaic power system using TRNSYS 17

Energy plays an important role in a country’s economic growth in the current energy scenario, the major problem is depletion of energy sources (non-renewable) are more than being formed. One of the prominent solutions is minimizing the use of fossil fuels by utilization of renewable energy resources. A photovoltaic system is an efficient option in terms of utilizing the solar energy resource. The electricity output produced by the photovoltaic systems depends upon the incident solar radiation. This paper examines the performance simulation of 200KW photovoltaic power system at VIT University, Vellore. The main objective of this paper is to correlate the results between the predicted simulation data and the experimental data. The simulation tool used here is TRNSYS. Using TRNSYS modelling prediction of electricity produced throughout the year can be calculated with the help of TRNSYS weather station. The deviation of the simulated results with the experimented results varies due to the choice of weather station. Results from the field test and simulation results are to be correlated to attain the maximum performance of the system.

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