Probabilistic analysis of weather data for a hybrid solar/wind energy system

In this paper, a procedure for the probabilistic treatment of solar irradiance and wind speed data is reported as a method of evaluating, at a given site, the electric energy generated by both a photovoltaic system and a wind system. The aim of the proposed approach is twofold: first, to check if the real probability distribution functions (PDFs) of both clearness index and wind speed overlap with Hollands and Huget and Weibull PDFs, respectively; and then to find the parameters of these two distributions that best fit the real data. Further, using goodness‐of‐fit tests, these PDFs are compared with another set of very common PDFs, namely the Gordon and Reddy and Lognormal functions, respectively. The results inform the design of a pre‐processing stage for the input of an algorithm that probabilistically optimizes the design of hybrid solar wind power systems. In this paper, the validity of the proposed procedure was tested using long‐term meteorological data from Acireale (Italy). Copyright © 2010 John Wiley & Sons, Ltd.     

Restructuring energy systems for sustainability? Energy transition policy in the Netherlands

Increasingly, researchers and policy makers are confronting the challenge of restructuring energy systems into more sustainable forms. A ‘transition management’ model, and its adoption in the Netherlands, is attracting attention. Starting from the socio-technical multi-level theory that informs ‘transition management’, we analyse the ‘energy transition’ project carried out by the Dutch Ministry of Economic Affairs. Despite considerable achievements, their approach risks capture by the incumbent energy regime, thereby undermining original policy ambitions for structural innovation of the energy system. This experience presents generic dilemmas for transitions approaches.     

Reimagining future energy systems: Overview of the US program to maximize energy utilization via integrated nuclear-renewable energy systems

A sustainable, balanced energy portfolio is necessary for a country's continued economic growth. This portfolio must collectively be able to provide reliable, resilient electricity at stable, affordable prices. Nuclear energy is an important contributor to global clean energy supply, both as a primary source and by complementing and enabling other clean energy sources. As we look to the design and operation of future energy systems, we see an increasing need to think differently about how we utilize our energy resources to meet all of our energy needs—not just electricity but also industrial and transportation demands. Resource utilization in light of a broader desire to reduce environmental impacts leads us to consider transforming how we use nuclear energy, which currently provides more than half of the nonemitting electricity generated in the United States. A paradigm shift is required to develop optimal energy generation and use configurations that embrace novel approaches to system integration and process design. The US Department of Energy (DOE) Office of Nuclear Energy (NE) program on Integrated Energy Systems (IES)—formerly the Nuclear-Renewable Hybrid Energy Systems (N-R HES) program—was established to evaluate potential options for the coordinated use of nuclear and renewable energy generators to meet energy demands across the electricity, industrial, and transportation sectors. These formerly independent sectors are becoming increasingly linked through technology advances in data acquisition, communications, demand response approaches, and control technologies. Advanced modeling and simulation tools can be employed to design systems that better coordinate across these sectors. Implementation of integrated multi-input, multi-output energy systems will allow for expanded use of nuclear energy beyond the grid in a manner that complements the increased build-out of variable renewable energy generation. These integrated systems would provide enhanced flexibility while also providing energy services and supporting the production of additional, nonelectric commodities (eg, potable water, hydrogen, and liquid fuels) via excess thermal and electrical energy from the nuclear system. Increased flexibility of traditionally baseload nuclear systems will support energy security, grid reliability, and grid resilience while maximizing the use of clean energy technologies. This paper provides an overview of current efforts in the United States that assess the potential to increase utilization of nuclear energy systems, in concert with renewable energy generation, via the IES program. Analysis tools and approaches and preliminary analysis results are summarized, and planned experimental activities to demonstrate integrated system performance are introduced.     

Performance analysis of various hybrid renewable energy systems using battery,hydrogen, and pumped hydro‐based storage units

The aim of this research is to analyze the techno‐economic performance of hybrid renewable energy system (HRES) using batteries, pumped hydro‐based, and hydrogen‐based storage units at Sharurah, Saudi Arabia. The simulations and optimization process are carried out for nine HRES scenarios to determine the optimum sizes of components for each scenario. The optimal sizing of components for each HRES scenario is determined based on the net present cost (NPC) optimization criterion. All of the nine optimized HRES scenarios are then evaluated based on NPC, levelized cost of energy, payback period, CO₂ emissions, excess electricity, and renewable energy fraction. The simulation results show that the photovoltaic (PV)‐diesel‐battery scenario is economically the most viable system with the NPC of US$2.70 million and levelized cost of energy of US$0.178/kWh. Conversely, PV‐diesel‐fuel cell system is proved to be economically the least feasible system. Moreover, the wind‐diesel‐fuel cell is the most economical scenario in the hydrogen‐based storage category. PV‐wind‐diesel‐pumped hydro scenario has the highest renewable energy fraction of 89.8%. PV‐wind‐diesel‐pumped hydro scenario is the most environment‐friendly system, with an 89% reduction in CO₂ emissions compared with the base‐case diesel only scenario. Overall, the systems with battery and pumped hydro storage options have shown better techno‐economic performance compared with the systems with hydrogen‐based storage.     

A review of computer tools for analysing the integration of renewable energy into various energy systems

This paper includes a review of the different computer tools that can be used to analyse the integration of renewable energy. Initially 68 tools were considered, but 37 were included in the final analysis which was carried out in collaboration with the tool developers or recommended points of contact. The results in this paper provide the information necessary to identify a suitable energy tool for analysing the integration of renewable energy into various energy-systems under different objectives. It is evident from this paper that there is no energy tool that addresses all issues related to integrating renewable energy, but instead the ‘ideal’ energy tool is highly dependent on the specific objectives that must be fulfilled. The typical applications for the 37 tools reviewed (from analysing single-building systems to national energy-systems), combined with numerous other factors such as the energy-sectors considered, technologies accounted for, time parameters used, tool availability, and previous studies, will alter the perception of the ‘ideal’ energy tool. In conclusion, this paper provides the information necessary to direct the decision-maker towards a suitable energy tool for an analysis that must be completed.     

A new approach of sizing battery energy storage system for smoothing the power fluctuations of a PV/wind hybrid system

In this paper, a new approach for optimally sizing the storage system employing the battery banks for the suppression of the output power fluctuations generated in the hybrid photovoltaic/wind hybrid energy system. At first, a novel multiple averaging technique has been used to find the smoothing power that has to be supplied by the batteries for the different levels of smoothing of output power. Then the battery energy storage system is optimally sized using particle swarm optimization according to the level of smoothing power requirement, with the constraints of maintaining the battery state of charge and keeping the energy loss within the acceptable limits. Two different case studies have been presented for different locations and different sizes of the hybrid systems in this work. The results of the simulation studies and detailed discussions are presented at the end to portrait the effectiveness of the proposed method for sizing of the battery energy storage system. Copyright © 2016 John Wiley & Sons, Ltd.     

Pre-feasibility study of stand-alone hybrid energy systems for applications in Newfoundland

A potential solution for stand-alone power generation is to use a hybrid energy system in parallel with some hydrogen energy storage. In this paper, a pre-feasibility study of using hybrid energy systems with hydrogen as an energy carrier for applications in Newfoundland, Canada is explained. Various renewable and non-renewable energy sources, energy storage methods and their applicability in terms of cost and performance are discussed. HOMER is used as a sizing and optimization tool. Sensitivity analysis with wind speed data, solar radiation level, diesel price and fuel cell cost was done. A remote house having an energy consumption of 25 kW h/d with a 4.73 kW peak power demand was considered as the stand-alone load. It was found that, a wind–diesel–battery hybrid system is the most suitable solution at present. However, with a reduction of fuel cell cost to 15% of its current value, a wind–fuel cell system would become a superior choice. Validity of such projection and economics against conventional power sources were identified. Sizing, performance and various cost indices were also analyzed in this paper.     

Optimisation of the hybrid renewable energy system by HOMER,PSO and CPSO for the study area

This study is based on simulation and optimisation of the renewable energy system of the police control room at Sagar in central India. To analyse this hybrid system, the meteorological data of solar insolation and hourly wind speeds of Sagar in central India (longitude 78°45′ and latitude 23°50′) have been considered. The pattern of load consumption is studied and suitably modelled for optimisation of the hybrid energy system using HOMER software. The results are compared with those of the particle swarm optimisation and the chaotic particle swarm optimisation algorithms. The use of these two algorithms to optimise the hybrid system leads to a higher quality result with faster convergence. Based on the optimisation result, it has been found that replacing conventional energy sources by the solar–wind hybrid renewable energy system will be a feasible solution for the distribution of electric power as a stand-alone application at the police control room. This system is more environmentally friendly than the conventional diesel generator. The fuel cost reduction is approximately 70–80% more than that of the conventional diesel generator.     

A dynamic MOPSO algorithm for multiobjective optimal design of hybrid renewable energy systems

In this paper, a dynamic multiobjective particle swarm optimization (DMOPSO) method is presented for the optimal design of hybrid renewable energy systems (HRESs). The main goal of the design is to minimize simultaneously the total net present cost (NPC) of the system, unmet load, and fuel emission. A DMOPSO‐simulation based approach has been used to approximate a worthy Pareto front (PF) to help decision makers in selecting an optimal configuration for an HRES. The proposed method is examined for a case study including wind turbines, photovoltaic (PV) panels, diesel generators, batteries, fuel cells, electrolyzer, and hydrogen tanks. Well‐known metrics are used to evaluate the generated PF. The average spacing and diversification metrics obtained by the proposed approach are 1386 and 4656, respectively. Additionally, the set coverage metric value shows that at least 67% of Pareto solutions obtained by DMOPSO dominate the solutions resulted by other reported algorithms. By using a sensitivity analysis for the case study, it is found that if the PV panel and wind turbine capital cost are decreased by 50%, the total NPC of the system would be decreased by 18.8 and 3.7%, respectively. Copyright © 2014 John Wiley & Sons, Ltd.     

Optimal hybrid renewable energy systems for energy security: a comparative study

A hybrid power system may be used to reduce dependency on either conventional energy or renewable systems. This article deals with the sizing, generator running hours, sensitivity analysis, optimisation, and greenhouse gas emission analysis of hybrid renewable energy systems (HRES). Two locations have been selected where the feasibility of using different hybrid systems is studied for the same load demand. One site is the small remote community of Amini in the Lakshadweep Islands, located in southern India in the Arabian Sea, where solar and/or wind energy is always available throughout the year to provide energy security. Another place is the rural township of Hathras, in the northern Indian state of Uttar Pradesh, where agricultural biomass is found in abundance for the whole year. A comparative study has been made for the two locations for the same load demand by simulating HRES. To achieve the goal of simulation, the hybrid optimisation model for electric renewables (HOMER) software of the National Renewable Energy Laboratory, USA, is used. An optimisation model of a hybrid renewable system has been prepared which simplifies the task of evaluating the design of an off-grid/standalone system. After simulating all possible system equipment with their sizes, a list of many possible configurations may be evaluated and sorted by net present cost to compare the design options. An elaborate sensitivity analysis has been used for each input variable; the whole optimisation process is repeated to get simulated system configurations     

A Metric Space with LCOE Isolines for Research Guidance in wind and hydrokinetic energy systems

This paper introduces a new Metric Space to guide the design of advanced wind energy systems and hydrokinetic energy converters such as tidal, ocean current and riverine turbines. The Metric Space can analyse farms that combine different or identical turbines and stand‐alone turbines. The first metric (M1) of the space considers the efficiency of the turbines in the farm, which is also proportional to the specific power per swept area at a given wind/water velocity (W/m²). The second metric (M2) describes the specific rotor area per unit of mass of the turbines (m²/kg). Both metrics depend on the primary design characteristics of the turbines, such as swept area, system size and mass, materials and efficiency, and are independent at first from external characteristics, such as atmospheric and ocean site conditions, cost of materials and economic factors. Combining both metrics, and for a given set of external characteristics, the resulting Metric Space M2/M1 displays the Levelized Cost of Energy (LCOE) standards as isolines. This graphical representation provides a quick understanding of the cost and state of the technology. It also offers a practical guidance to choose the research tasks and strategy to design advanced wind and hydrokinetic energy systems. The paper applies the new Metric Space to several case studies, including large and small onshore wind turbines, floating and bottom‐fixed offshore wind turbines, downwind rotors, multi‐rotor and hybrid systems, airborne wind energy systems, wind farms and tidal energy converters.     

广东可再生能源利用及发展研究

阐述了广东利用和发展可再生能源的必要性，分析了广东利用和发展可再生能源的有利条件，提出了广东可再生能源发展的重点及对策。     

Utility-scale solar photovoltaic hybrid system and performance analysis for eco-friendly electric vehicle charging and sustainable home

Electricity energy has a crucial importance role for social and economic developments all over the world. Nowadays, the worldwide generation of electricity mostly depends on conventional sources. These sources are limited in the environment and also responsible for ecological problems like environmental pollution. Renewable energy sources have important aspects such as feasibility, efficiency, and environment-friendly in comparison to conventional energy resources. In order to overcome environmental problems, this proposed study focuses on solar photovoltaic hybrid system for eco-friendly electric vehicle charging and house based on machine learning system. In order to realize numerical study, Homer Pro and PVSOL software are used. Various parameters of economic feasibility, sizing strategies with logical advancements, and optimization methods are numerically considered and analyzed to compare measurement one.     

风光互补独立供电系统优化匹配设计实例

以系统的最小安装成本为优化目标,以系统的供电可靠性为约束条件,对内蒙古满洲里市某居民家庭用电风光互补独立供电系统进行基于计算机仿真计算的优化匹配设计。     

Experimental results for hybrid energy storage systems coupled to photovoltaic generation in residential applications

An experimental solar-hydrogen powered residence simulator was built and tested. The system consisted of a solar photovoltaic array connected to an electrolyzer which produced hydrogen as a means of energy storage. The hydrogen was used to produce electricity in a fuel cell that operated in parallel with a battery to meet dynamic power demand similar to that found in residential applications. The study demonstrated the technical feasibility of operating such a system under the simultaneous dynamics of solar input and load. Limitations of current fuel cell and electrolyzer designs, as they pertain to both power delivery and energy storage, were identified. The study also established the need to understand and address dynamic performance in the design and application of solar-hydrogen reversible fuel cell hybrid systems. An economic analysis found that major cost reductions would need to be achieved for such systems to compete with conventional energy storage devices.     

Energy supply for water electrolysis systems using wind and solar energy to produce hydrogen: a case study of Iran

Due to acute problems caused by fossil fuels that threaten the environment, conducting research on other types of energy carriers that are clean and renewable is of great importance. Since in the past few years hydrogen has been introduced as the future fuel, the aim of this study is to evaluate wind and solar energy potentials in prone areas of Iran by the Weibull distribution function (WDF) and the Angstrom-Prescott (AP) equation for hydrogen production. To this end, the meteorological data of solar radiation and wind speed recorded at 10 m height in the time interval of 3 h in a five-year period have been used. The findings indicate that Manjil and Zahedan with yearly wind and solar energy densities of 6004 (kWh/m²) and 2247 (kWh/m²), respectively, have the greatest amount of energy among the other cities. After examining three different types of commercial wind turbines and photovoltaic (PV) systems, it becomes clear that by utilizing one set of Gamesa G47 turbine, 91 kg/d of hydrogen, which provides energy for 91 car/week, can be produced in Manjil and will save about 1347 L of gasoline in the week. Besides, by installing one thousand sets of X21-345 PV systems in Zahedan, 20 kg/d of hydrogen, enough for 20 cars per week, can be generated and 296 L of gasoline can be saved. Finally, the RETScreen software is used to calculate the annual CO₂ emission reduction after replacing gasoline with the produced hydrogen.     

Evaluation of small wind turbines in distributed arrangement as sustainable wind energy option for Barbados

The island of Barbados is 99% dependent on fossil fuel imports to satisfy its energy needs, which is unsustainable. This study proposes a 10 MW distributed wind energy scheme using micro wind turbines (WT) of horizontal (HAWT) and vertical axis (VAWT) configurations. These units are rated less than 500 W, and the scheme is hereafter referred to as mWT10. mWT10 is compared to the proposed 10 MW medium WT farm by the Barbados Light & Power Company (BL&P). The economic bottom line is the levelized cost of electricity (LCOE). The results highlight the BL&P proposal as the best economic option at BDS$0.19 per kWh, while that of both mWT10 configurations exceeds the conventional cost of BDS$0.25 by two to nine times. This is attributed to significantly higher relative installation and operational costs. However, the financial gap between mWT10 LCOE and the retail price of electricity is much smaller due to a large fuel surcharge passed on to each customer. Annual additional benefits of using wind energy include: greenhouse gas emissions savings of 6–23 kt of carbon dioxide; and anavoided fuel costs of BDS$1.5–5.3 million.

The distributed mWT10 using HAWTs competes directly with the BL&P farm, however, it provides these benefits without the visual or ecological impacts of the larger machines. Conversely, VAWTs have features that favour a visually discrete and widely repeatable scheme but suffer relatively high costs. Therefore, this study illustrates the great potential of small wind turbines to be competitive with conventional wind farms, thus challenging the small wind industry to meet its potential by producing reliable and robust machines at lower cost.     

An investigation of optimum PV and wind energy system capacities for alternate short and long‐term energy storage sizing methodologies

The goal of this study is to find the optimal sizes of renewable energy systems (RES) based on photovoltaic (PV) and/or wind systems for three energy storage system (ESS) scenarios in a micro‐grid; (1) with pumped hydro storage (PHS) as a long‐term ESS, (2) with batteries as a short‐term ESS, and (3) without ESS. The PV and wind sizes are optimally determined to accomplish the maximum annual RES fraction (F_RES ) with electricity cost lower than or equal to the utility tariff. Furthermore, the effect of the use of battery and PHS on the electricity cost and F_RES are studied. A university campus on a Mediterranean island is selected as a case study. The results show that PV‐wind hybrid system of 8 MW wind and 4.2 MW PV with 89.5 MWh PHS has the highest F_RES of 88.0%, and the highest demand supply fraction as 42.6%. Moreover, the results indicate that the economic and technical parameters of RESs are affected significantly by the use of ESSs depending on the type and the capacity of both the RES and the ESS.     

The system performance of autonomous photovoltaic–wind hybrid energy systems using synthetically generated weather data

The yearly system performance of autonomous photovoltaic–wind hybrid energy systems with battery storage is the subject of this article. The yearly system performance is simulated using synthetically generated solar radiation and wind speed data and compared to that simulated using measured hour-by-hour data. Two different synthetic weather data sets are generated: 3-day month and 4-day month, in which 3 and 4 days represent a month, resulting in a total of 36 and 48 days for a year. The hourly varying solar radiation data are synthesised from the clearness index value for each month. The daily constant wind speed data are synthesised using the Weibull wind speed distribution model, on a monthly basis. Using two different synthetic weather data sets, the effect of number of synthetic days on the system performance estimation is studied. Different sequences of synthetic solar and wind days lead to 36 and 576 combinations for 3- and 4-day months, respectively. Three predetermined combinations for both the 3- and 4-day months are chosen and the system performance of an autonomous photovoltaic–wind hybrid energy system with battery storage is simulated using these predetermined combinations. It is shown that the yearly system performance predicted from the 3- and 4-day synthetic data closely agrees with that obtained from the measured data, varying only slightly for different combinations.     

A simplified model for estimating yearly wind fraction in hybrid-wind energy systems

This article presents a simplified algorithm to estimate the yearly wind fraction, the fraction of energy demand provided by wind generator, in a hybrid-wind system (typically a PV-wind) with battery storage. The novel model is drawn based on the simulation results, using 8-year long measured hour-by-hour wind speed data from five different locations throughout the world. The simulation program simulates the battery state of voltage (SoV) and is able to predict the wind fraction for a period of time, typically monthly or yearly. The yearly wind fraction values obtained from the simulations are plotted against the ratio of energy to load for various battery storage capacities to obtain wind fraction curves. The novel method correlates the yearly wind fraction with the parameters of the Weibull distribution function, thus, offering a general methodology. The yearly wind fraction curves are mathematically represented using a 2-parameter model. The novel algorithm is validated by comparing the simulated wind fraction values with those calculated from the simplified algorithm. The standard error of estimation of the WF from the simplified algorithm is further presented for each battery capacity.