On the value of decentralised PV systems for the GCC residential sector

Based on the rich natural potential of the Gulf region, solar energy is expected to play a greater role in the future of the Gulf Corporation Council (GCC) countries. This study examines whether the integration of the photovoltaic (PV) into individual residential buildings in the GCC countries is worth the investment. A prototype residential building is developed and a building integrated photovoltaic (BiPV) system is then designed. The system performance is simulated, and through economic analysis, it is shown that the current BiPV technology is not a cost-effective option for the GCC countries based on the present electricity tariff, PV system cost and system efficiency. The only way such a system would be viable with current technology is if the electricity tariff were to increase substantially. However, if the tariff remains constant for the foreseeable future, BiPV solar energy technology will only be feasible if the total system cost drops drastically. This study shows that BiPV systems offer cost reductions in both energy and economic terms over centralised PV plants, especially if the costs of avoided building construction materials are taken into account. To bring about the benefits of BiPV technology for the GCC residential sector, therefore, the first logical and most practical step is the implementation of a continuous promotion strategy that consists of both subsidies for investments and reasonable tariffs.     

Photovoltaic energy mini-generation: Future perspectives for Portugal

This paper evaluates the benefits of developing the mini-generation PV market in Portugal. It presents the legal framework and current status of the Portuguese PV electricity sector, and compares the country to other European nations: France, Germany, Greece, Italy, Spain and the United Kingdom. A model that combines PVGIS with a self-developed financial tool is used to assess the feasibility of a 150 kW mini-generation system using five different technologies: fixed mount, single-axis tracking, double-axis tracking, low concentration and medium concentration (MCPV). The profitability of the mini-generation systems in the seven countries studied is calculated and compared. According to this analysis, MCPV and, of the conventional technologies, the single-axis tracking systems are the most profitable technologies. Despite the attractiveness of the current Portuguese feed-in tariffs and of the abundant solar resource, investors are discouraged and the country's PV market is far from mature. Specific mini-generation regulations should focus on a fast and transparent licensing procedure and should promote the access to financing. This would attract new investments, which would result in the growth of the PV electricity produced, and would help Portugal to meet its European Union Renewable Energy targets.     

A comparative life cycle energy cost analysis of photovoltaic and fuel generator for load shedding application

Comparative life cycle energy cost analysis for different electricity generators (photovoltaic generator, kerosene generator and diesel generator) used during load shedding is presented. The parameters considered for calculation of the unit cost of energy are: the discount rate, inflation rate, IREDA loan facility to promote PV, operation and maintenance cost of PV and fuel generator (FG) set and the associated fuel cost. It is found that the unit cost of PV electricity is comparable to or less than that of FG generated electricity at present market prices.     

Assessment of hydrogen as a potential energy storage for urban areas’ PV-assisted energy systems - Case study

The world is experiencing unprecedented development in the clean energy sector in residential and industrial applications. This paper provides a case study assessing different scenarios of greenizing the electrical energy demand in El-Mostakbal city in Egypt. Three scenarios are studied with consideration of a photovoltaic (PV) system integrated with the grid-connected city with different integrated system configurations. The scenarios for the grid-connected city are scenario-I: only PV, scenario-II: PV with batteries for electricity storage along with grid electricity, and scenario-III: PV with hydrogen production, storage, and utilization for covering the electric demand along with grid electricity, these scenarios are assessed technoeconomically, and the results show an optimized case where the electricity demand of the city can be met with 64.3% produced from solar energy, at $71.7 M of the net present cost.     

Lower electricity prices and greenhouse gas emissions due to rooftop solar: empirical results for Massachusetts

Monthly and hourly correlations among photovoltaic (PV) capacity utilization, electricity prices, electricity consumption, and the thermal efficiency of power plants in Massachusetts reduce electricity prices and carbon emissions beyond average calculations. PV utilization rates are highest when the thermal efficiencies of natural gas fired power plants are lowest, which reduces emissions of CO₂ and CH₄ by 0.3% relative to the annual average emission rate. There is a positive correlation between PV utilization rates and electricity prices, which raises the implied price of PV electricity by up to 10% relative to the annual average price, such that the average MWh reduces electricity prices by $0.26–$1.86 per MWh. These price reductions save Massachusetts rate-payers $184 million between 2010 and 2012. The current and net present values of these savings are greater than the cost of solar renewable energy credits which is the policy instrument that is used to accelerate the installation of PV capacity. Together, these results suggest that rooftop PV is an economically viable source of power in Massachusetts even though it has not reached socket parity.     

Hybrid application of biogas and solar resources to fulfill household energy needs: A potentially viable option in rural areas of developing countries

The absence of clean cooking facilities and electricity means billions of rural people are deprived of much needed socioeconomic development. Livestock residues (dung) and solar radiation are two renewable energy resources that are abundantly available in rural areas of developing countries. Although it is not feasible for these two resources separately to meet both thermal (cooking) and electricity demands, hybrid applications have not been given due attention. To facilitate integrating these two resources in rural energy planning, and to promote their dissemination through hybrid applications, it is necessary to evaluate their economic merits, and assess their ability to deal with the demands. In this paper, we examine the techno-economic performance of hybrid applications of these two resources by applying a simulation technique using the HOMER tool, and by giving derived cost-saving equations. We also quantify the monetary savings from replacing traditional fuels, and perform a sensitivity analysis on a number of variables (e.g. dung cost, fuelwood cost) to see how they affect the performance of different energy supply alternatives. Furthermore, we examine the practical applicability of the biogas system in the households through a structured survey of 72 ongoing household biogas plants. This study finds that households that have between three and six cattle can potentially meet their cooking and electricity loads through a hybrid implementation of biogas and solar PV (Photovoltaic) system. By replacing conventional fuels households can achieve savings that are more than the total annualized costs incurred for installing new services.     

PV self-consumption optimization with storage and Active DSM for the residential sector

With the rising prices of the retail electricity and the decreasing cost of the PV technology, grid parity with commercial electricity will soon become a reality in Europe. This fact, together with less attractive PV feed-in-tariffs in the near future and incentives to promote self-consumption suggest, that new operation modes for the PV Distributed Generation should be explored; differently from the traditional approach which is only based on maximizing the exported electricity to the grid. The smart metering is experiencing a growth in Europe and the United States but the possibilities of its use are still uncertain, in our system we propose their use to manage the storage and to allow the user to know their electrical power and energy balances. The ADSM has many benefits studied previously but also it has important challenges, in this paper we can observe and ADSM implementation example where we propose a solution to these challenges. In this paper we study the effects of the Active Demand-Side Management (ADSM) and storage systems in the amount of consumed local electrical energy. It has been developed on a prototype of a self-sufficient solar house called “MagicBox” equipped with grid connection, PV generation, lead-acid batteries, controllable appliances and smart metering. We carried out simulations for long-time experiments (yearly studies) and real measures for short and mid-time experiments (daily and weekly studies). Results show the relationship between the electricity flows and the storage capacity, which is not linear and becomes an important design criterion.     

Levelized cost of electricity (LCOE) of renewable energies and required subsidies in China

The development and utilization of renewable energy (RE), a strategic choice for energy structural adjustment, is an important measure of carbon emissions reduction in China. High cost is a main restriction element for large-scale development of RE, and accurate cost estimation of renewable power generation is urgently necessary. This is the first systemic study on the levelized cost of electricity (LCOE) of RE in China. Results indicate that feed-in-tariff (FIT) of RE should be improved and dynamically adjusted based on the LCOE to provide a better support of the development of RE. The current FIT in China can only cover the LCOE of wind (onshore) and solar photovoltaic energy (PV) at a discount rate of 5%. Subsidies to renewables-based electricity generation, except biomass energy, still need to be increased at higher discount rates. Main conclusions are drawn as follows: (1) Government policy should focus on solving the financing problem of RE projects because fixed capital investment exerts considerable influence over the LCOE; and (2) the problem of high cost could be solved by providing subsidies in the short term and more importantly, by reforming electricity price in the mid-and long-term to make the RE competitive.     

Assessing the strength and effectiveness of renewable electricity feed-in tariffs in European Union countries

In the last two decades, feed-in tariffs (FIT) have emerged as one of the most popular policies for supporting renewable electricity (RES-E) generation. A few studies have assessed the effectiveness of RES-E policies, but most ignore policy design features and market characteristics (e.g. electricity price and production cost) that influence policy strength. We employ 1992–2008 panel data to conduct the first econometric analysis of the effectiveness of FIT policies in promoting solar photovoltaic (PV) and onshore wind power development in 26 European Union countries. We develop a new indicator for FIT strength that captures variability in tariff size, contract duration, digression rate, and electricity price and production cost to estimate the resulting return on investment. We regress this indicator on added RES-E capacity using a fixed effects specification and find that FIT policies have driven solar PV development in the EU. However, this effect is overstated without controlling for country characteristics and is concealed without accounting for policy design. We do not find robust evidence that FIT policies have driven wind power development. Overall, we show that the interaction of policy design, electricity price, and electricity production cost is a more important determinant of RES-E development than policy enactment alone.     

Adoption of residential solar power under uncertainty: Implications for renewable energy incentives

Many incentives at the state and federal level exist for household adoption of renewable energy like solar photovoltaic (PV) panels. Despite generous financial incentives the adoption rate is low. We use the option value framework, which takes into account the benefit of delaying investment in response to uncertainty, to examine the decision by households to invest in solar PV. Using a simulation model, we determine optimal adoption times, critical values of discounted benefits, and adoption rates over time for solar PV investments using data from Massachusetts. We find that the option value multiplier is 1.6, which implies that the discounted value of benefits from solar PV needs to exceed installation cost by 60% for investment to occur. Without any policies, median adoption time is eight years longer under the option value decision rule compared to the net present value decision rule where households equate discounted benefits to installation cost. Rebates and other financial incentives decrease adoption time, but their effect is attenuated if households apply the option value decision rule to solar PV investments. Results suggest that policies that reduce the uncertainty in returns from solar PV investments would be most effective at incentivizing adoption.     

Making the case for grid-connected photovoltaics in Brazil

In the developed world, grid-connected photovoltaics (PVs) are the fastest-growing segment of the energy market. From 1999 to 2009, this industry had a 42% compound annual growth-rate. From 2009 to 2013, it is expected to grow to 45%, and in 2013 the achievement of grid parity – when the cost of solar electricity becomes competitive with conventional retail (including taxes and charges) grid-supplied electricity – is expected in many places worldwide. Grid-connected PV is usually perceived as an energy technology for developed countries, whereas isolated, stand-alone PV is considered as more suited for applications in developing nations, where so many individuals still lack access to electricity. This rationale is based on the still high costs of PV when compared with conventional electricity. We make the case for grid-connected PV generation in Brazil, showing that with the declining costs of PV and the rising prices of conventional electricity, urban populations in Brazil will also enjoy grid parity in the present decade. We argue that governments in developing nations should act promptly and establish the mandates and necessary conditions for their energy industry to accumulate experience in grid-connected PV, and make the most of this benign technology in the near future.     

Integrated high-concentration PV near-term alternative for low-cost large-scale solar electric power

Large-scale photovoltaic electric power generation deployment and utilization is no longer dictated by limitations in technology, but rather by the economics of PV systems vs. other renewable or traditional options. This paper describes a near-term alternative option for cost-effective solar electric power generation based on a novel sunlight concentrating technology: integrated high-concentration PV(IHCPV). The advantages of high-concentration systems have been well analyzed, but development was constrained by the lack of solar cell capable of withstanding the rigors of concentrated sunlight. The development of a stable, high-concentration back-junction, point-contact cell, by Amonix, paved the way for high-concentration system development. System designers had to insure that the cost savings inherent in concentration systems through the reduction of costly solar cell content were not over-shadowed by the ancillary costs of structure and tracking elements used in concentrating arrays. The IHCPV system has met these goals. Economic factors specific to the IHCPV system are presented including (1) low cost of entry, (2) enhanced energy production, (3) reduced and utilization, and (4) accelerated benefits of volume production.     

“八面玲珑展威风”——介绍一种新的“采用数倍聚光的光伏发电系统”

尽管太阳能是发展潜力最大的可再生能源资源,但由于太阳能光电的成本远远高于风电、生物质发电,使得人们对太阳能的大规模利用还依然是一种奢望。那么,如何使太阳能从“高处不胜寒”的境遇走入寻常百姓家呢?关键在于技术突破!本文介绍的“采用数倍聚光的光伏发电系统”使我们看到了太阳能光电大规模发展的希望。根据陈应天教授的聚光和跟踪理论而开发的这种系统,可以使太阳能光电成本比传统的平板固定式光电技术降低1倍!本文以详实的数据介绍了这项完全自主创新的新技术的特点和经济优势。在我国风电、生物质发电技术落后并受制于国外技术垄断的情形下,这项新技术的示范推广,将是我国在太阳能利用方面的重要突破。     

Optimization of operational cost for a grid-supporting PV system with battery storage

Coupling an energy storage to a photovoltaic (PV) system not only increases the self-consumption but also solves the over-voltage issues if the cycling of the storage is properly controlled. Whatever the application the storage is used for, the primary concern of the system owner is to maximize the profits. Therefore, this paper addresses an energy management system for a PV system coupled with battery energy storage, which maximizes the daily economic benefits while curtailing the power injection to the grid in such a way that helps to mitigate over-voltage problems caused by reverse power flow. A time dependent grid feed-in limit is proposed achieve this objective. The daily operational cost that includes the energy cost and the battery degradation cost is considered as the objective function. The non-linear constrained optimization problem is solved using dynamic programming. The analyses are made to investigate the economic benefits of charging the battery from the grid. It is found that there is a possibility for these systems for participating in load-levelling if batteries are charged from the PV system. In order for that to be feasible, the peak-hour sell-back price for the energy from storage should be higher than the off-peak utility electricity price.     

Life cycle assessment study of solar PV systems: An example of a 2.7 kWp distributed solar PV system in Singapore

In life cycle assessment (LCA) of solar PV systems, energy pay back time (EPBT) is the commonly used indicator to justify its primary energy use. However, EPBT is a function of competing energy sources with which electricity from solar PV is compared, and amount of electricity generated from the solar PV system which varies with local irradiation and ambient conditions. Therefore, it is more appropriate to use site-specific EPBT for major decision-making in power generation planning. LCA and life cycle cost analysis are performed for a distributed 2.7 kW_p grid-connected mono-crystalline solar PV system operating in Singapore. This paper presents various EPBT analyses of the solar PV system with reference to a fuel oil-fired steam turbine and their greenhouse gas (GHG) emissions and costs are also compared. The study reveals that GHG emission from electricity generation from the solar PV system is less than one-fourth that from an oil-fired steam turbine plant and one-half that from a gas-fired combined cycle plant. However, the cost of electricity is about five to seven times higher than that from the oil or gas fired power plant. The environmental uncertainties of the solar PV system are also critically reviewed and presented.     

Climate change impacts on techno-economic performance of roof PV solar system in Australia

The techno-economic performance of roof PV solar system depends on local climatic conditions. The energy conversion behavior of PV system will change as a result of the new solar irradiation data caused by climate change. This study aims to investigate the quantified impacts of climate change on the future performance of PV roof system with a general electricity load and legal maximum size of solar array. In this study, the morphing method is employed to predict the future hourly mean global solar irradiation data for the year 2030, 2050 and 2070. By using the current and future solar irradiation data as the inputs, a simulation model of PV system is built to simulate the long-term implementation of the systems in the capital cities of Australian states. The solutions of the model given by computer programme, includes the system's electricity generation, greenhouse gas emissions, and cost of energy are analysed, and all the solutions are compared between different climatic conditions of all the capital cities. It is shown that there is a nearly linear correlation between the increase of average external air temperature and the increase of solar irradiation from 2030 to 2070. For the PV system in the majority of cities, a 10–20% increase of economic costs between the 2030 and 2050 climate scenario would be required. It is also found that the Hoba system has the best techno-economic performance with the lowest economic costs and higher renewable fraction, at both current climate and future climate.     

Financial assessment of government subsidy policy on photovoltaic systems for industrial users: A case study in Taiwan

Due to Taiwan's limited energy resources, the development of solar photovoltaic (PV) in Taiwan has become one of the most important solutions for meeting future energy supply needs and ensuring environmental protection. A huge amount of researches about renewable energy sources has emerged recently in response to these issues. However, the amount of researches considering the effects of various influential parameters on the efficiency and performance of PV systems remains small, and is still limited to some specific parts of PV systems. In particular, researches considering thoughtfully the influence of government subsidies on PV financial assessment are still in development. This paper proposes an approach to analyze the benefit of installing a PV system under the impact of government financial subsidies, focusing especially on feed-in-tariff (FIT) and tax abatement policies for industrial users in Taiwan. In addition, a method for selecting the most appropriate policies is proposed for the government through the analysis of both user demand and the government's PV installation capacity target.     

Solar photovoltaic (PV) energy; latest developments in the building integrated and hybrid PV systems

Environmental concerns are growing and interest in environmental issues is increasing and the idea of generating electricity with less pollution is becoming more and more attractive. Unlike conventional generation systems, fuel of the solar photovoltaic energy is available at no cost. And solar photovoltaic energy systems generate electricity pollution-free and can easily be installed on the roof of residential as well as on the wall of commercial buildings as grid-connected PV application. In addition to grid-connected rooftop PV systems, solar photovoltaic energy offers a solution for supplying electricity to remote located communities and facilities, those not accessible by electricity companies.The interest in solar photovoltaic energy is growing worldwide. Today, more than 3500 MW of photovoltaic systems have been installed all over the world. Since 1970, the PV price has continuously dropped [8]. This price drop has encouraged worldwide application of small-scale residential PV systems. These recent developments have led researchers concerned with the environment to undertake extensive research projects for harnessing renewable energy sources including solar energy. The usage of solar photovoltaic as a source of energy is considered more seriously making future of this technology looks promising.The objective of this contribution is to present the latest developments in the area of solar photovoltaic energy systems. A further objective of this contribution is to discuss the long-term prospect of the solar photovoltaic energy as a sustainable energy supply.     

Technico-economic analysis of off grid solar PV/Fuel cell energy system for residential community in desert region

A technico-economic analysis based on integrated modeling, simulation, and optimization approach is used in this study to design an off grid hybrid solar PV/Fuel Cell power system. The main objective is to optimize the design and develop dispatch control strategies of the standalone hybrid renewable power system to meet the desired electric load of a residential community located in a desert region. The effects of temperature and dust accumulation on the solar PV panels on the design and performance of the hybrid power system in a desert region is investigated. The goal of the proposed off-grid hybrid renewable energy system is to increase the penetration of renewable energy in the energy mix, reduce the greenhouse gas emissions from fossil fuel combustion, and lower the cost of energy from the power systems. Simulation, modeling, optimization and dispatch control strategies were used in this study to determine the performance and the cost of the proposed hybrid renewable power system. The simulation results show that the distributed power generation using solar PV and Fuel Cell energy systems integrated with an electrolyzer for hydrogen production and using cycle charging dispatch control strategy (the fuel cell will operate to meet the AC primary load and the surplus of electrical power is used to run the electrolyzer) offers the best performance. The hybrid power system was designed to meet the energy demand of 4500 kWh/day of the residential community (150 houses). The total power production from the distributed hybrid energy system was 52% from the solar PV, and 48% from the fuel cell. From the total electricity generated from the photovoltaic hydrogen fuel cell hybrid system, 80.70% is used to meet all the AC load of the residential community with negligible unmet AC primary load (0.08%), 14.08% is the input DC power for the electrolyzer for hydrogen production, 3.30% are the losses in the DC/AC inverter, and 1.84% is the excess power (dumped energy). The proposed off-grid hybrid renewable power system has 40.2% renewable fraction, is economically viable with a levelized cost of energy of 145 $/MWh and is environmentally friendly (zero carbon dioxide emissions during the electricity generation from the solar PV and Fuel Cell hybrid power system).     

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.