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In India, solar tariff has been witnessing a continuous fall since the announcement of revised targets for the National Solar Mission (NSM) in the year 2015. This paper discusses components that decide the solar tariff and demonstrates the role of various incentives being provided in bridging the tariff gap between solar and conventional power. The paper concludes with a comparison of various incentives (viability gap funding (VGF), accelerated depreciation (AD), generation-based incentive (GBI), etc.) based on the cost-effectiveness index. Based on the analysis, it is recommended that as levelised cost of energy (LCOE) is coming down, the government may think of pulling back some of the incentive schemes such as VGF, AD, and GBI while some hidden incentive schemes such as waiver of inter and/or intrastate transmission charges and losses, etc may continue. [ABSTRACT FROM AUTHOR]

The paper investigates state policy to promote solar energy in Latvia's and Ukraine's households. Comparing different approaches to stimulating sectors' development in both countries, the article evaluates the economic efficiency of solar power plants implementation based on the Levelized Cost of Electricity method and investment projects payback periods. The calculations were performed for solar power plants installed capacities ranging from 1 to 30 kW. The results revealed the fundamental differences in solar energy advancement due to the existing support mechanisms in the countries. While high feed-in tariff rates contribute to the rapid deployment of solar power plants in Ukraine's, Latvia's net-metering system hinders solar energy development in households. The research forms recommendations for improving policy by adjusting Ukrainian feed-in tariffs to trends in reducing solar energy costs, introducing solar energy in the Mandatory Procurement Component for Latvia, and applying preferential public financing to solar power plants construction in both states. Highlights State policy to promote solar energy in Ukraine's and Latvia's homes is analyzed The economic efficiency of small solar power plants is estimated for both countries Feed-in tariff in Ukraine ensures a quick payback period for solar power projects Net metering in Latvia does not provide investment attractiveness of solar plants Both countries need energy policy changes for balanced solar power development [ABSTRACT FROM AUTHOR]

This paper presents the electrical performance of organic photovoltaic modules (OPVs) on top of a polyethylene covered greenhouse high tunnel in a Mediterranean climate. Modules from a previous study were kept on the tunnel and monitored together with new modules with improved connectors installed on the greenhouse roof and on frames adjacent to the greenhouse. Measured module power conversion efficiencies ranged from 1% to 3%. The typical combined output of the modules across the tunnel roof were 105Wh on a sunny day and 81Wh on a cloudy day. Module burn-in period was about 15 days, losing around 36% of its initial efficiency. Ts80 lifetimes ranged from 7 days to 94 days. Tunnel integration was shown to accelerate module degradation. [ABSTRACT FROM AUTHOR]

The paper deals with the solar energy promotion in households in Ukraine. Despite the positive dynamics of solar power plants construction, today the share of electricity, generated on their basis, in the country's electricity mix remains insignificant. The main reason for this is the need for essential start-up investments. Since the economic efficiency of investment projects depends on installed capacity of plants, the structure and cost of the project financing sources; the paper focuses on estimation of financial sustainability of solar photovoltaic power plants construction under the credit programme 'Eco-Energy'. The obtained results show the high profitability of own and credit resources' investment in the considered projects that varies from 78.91% for the 10 kW solar power plants to 128.04% for the 30 kW ones. On this basis, policy recommendations for improving financing and other economic mechanisms to enhance renewable energy development in Ukrainian households have been developed. [ABSTRACT FROM AUTHOR]

The photovoltaic-thermal (PV/T) hybrid collector is the most generative technology solar energy, which has been invented to utilise electrical energy and heat from the solar system. This paper presents a numerical analysis and experimental validation of the thermal and electrical behaviour of the air PV/T collector based on the geometric design and the Tunisia climate conditions. PV/T system has lower thermal efficiency and higher electrical efficiency (14%) at high wind speeds. To improve the thermal efficiency, a sensitivity analysis studied across a range of the air channel depth (0.01–0.08 m) with different air mass flow rate. It was concluded that the thermal energy for a PV/T air system depends on the optimal depth and variations in mass flow rate. [ABSTRACT FROM AUTHOR]

The Levelised Cost of Energy is frequently used for assessing the economic competitiveness across different technologies. Unfortunately, there are caveats and a significant problem is that opportunity costs are ignored. This paper therefore addresses how to calculate the Levelised Cost of Energy for Solar Photovoltaics more correctly than today starting from the premise that an energy source has to guarantee an output at a system level. Thus, energy storage systems are required. Furthermore, uncertainty must be handled, and Monte Carlo methods are used here. The lowest Levelised Cost of Energy occurs when the system is designed for continuous operation, as opposed to peak shaving, with 80% of its solution space found between 203 USD/MWh to 252 USD/MWh and an expected value of 226 USD/MWh. This is almost 3 times higher than a narrowly defined Levelised Cost of Energy, which ignores opportunity costs. Hence, it is clear that Solar Photovoltaics can guarantee output within economically feasible limits, albeit currently expensive. [ABSTRACT FROM AUTHOR]

As the share of variable generation in power systems increases, there is increasing value in more flexible use and generation of electricity. The paper compares the economic value of several flexibility options in a large power system with a large amount of reservoir hydro power. Generation planning models are needed to consider the impact of flexibility options on other investments in a power system. However, generation planning models do not include all the relevant operational details. The approach in the paper combines a generation planning model with a unit commitment and dispatch model. The results demonstrate the value of coupling the heat and power sectors and the value of transmission. Low-cost electricity storage does not appear to be as decisive in the Northern European context with wind power as the main variable generation source. The paper also addresses methodological issues related to the inclusion of operational constraints in generation planning. [ABSTRACT FROM AUTHOR]

Consumption of fossil fuel generated electrical energy can be reduced substantially by the application of renewable energy systems in transportation-related facilities like airports. This paper focuses on present trend of usage of three domestic airports of India located geographically at different locations and proposes a detailed design and feasibility analysis of grid-connected solar photovoltaic power plants for three airports located at Udaipur, Raipur and Aurangabad. The capacity of solar PV power plants designed at Udaipur, Raipur and Aurangabad airports are 2.43 MWp, 3.20 MWp and 2.08 MWp respectively. Carbon dioxide emission reduction due to the energy generated by solar PV power plants at Udaipur, Raipur and Aurangabad airports are 3919.156 tCO2, 4634.596 tCO2 and 3167.559 tCO2 respectively. [ABSTRACT FROM AUTHOR]

Israel's Southern Arava region has experienced a boom in solar infrastructure development since 2011. Public acceptance of renewable energy installations is key to their successful implementation. The objective of this paper is to understand the level of acceptance of solar installations among Southern Arava communities and identify the factors that contributed to the widespread implementation of solar infrastructure in the region. Surveys and semi-structured interviews were distributed to five local kibbutz communities and local solar developers to gauge their attitudes about renewable technology in general and their acceptance of solar installations in their community. The results point to strong acceptance of solar technology in this region. Several factors contributed to this high level of support including kibbutz co-ownership of solar assets, transparent communication between stakeholders, and the kibbutz decision-making structure. [ABSTRACT FROM AUTHOR]

The demand for solar photovoltaic (SPV) systems is growing all over the world due to the continuous increase in the cost of conventional means of power. India has the advantage of around 300 clear sunny days in a year. However, the biggest problem is conversion efficiency. In this paper, an attempt has been made for evaluating the second law efficiency of 160 Wp stand-alone SPV systems installed in RKGIT Ghaziabad premises. The performance of a SPV system depends on climate conditions like temperature, air velocity and a number of sunny days. The solar energy striking the solar panels gets converted into electric and thermal energy. In this work, we have considered the effect of ambient temperature and air velocity on the efficiency of solar panels. The average second law efficiency of SPV systems was found to be 10.7%, whereas maximum second law efficiency was 13.8% at 9am on the same day. The efficiency of the SPV system can be improved by maintaining the temperature of the module. [ABSTRACT FROM AUTHOR]

In the present scenario, all over the world, electrical energy is produced by conventional or non-renewable energy supply system. These systems produce a large amount of atmospheric pollution. This predicament is principally conquered by the concentrated use of alternative or renewable energy system. The research work reported in the paper shows the profoundness of performance prediction and investigation of solar-tidal integrated renewable energy system using a different optimisation technique. The works on macro-level include a novel tidal-solar system in the coastal area of Cochin, India and modelling of tidal-solar energy system by the HOMER software. Duration of the project is assessed by a project management technique critical path method, optimisation of the HOMER software cost assessment result for the study area using teaching, learning-based optimisation, cuckoo optimisation and through the grasshopper technique, further reliability and life-cycle analysis of the system and result are validated by regression analysis. [ABSTRACT FROM AUTHOR]

Solar-driven trigeneration systems are able to cover all the building energy needs in heating, cooling and electricity using only the solar energy. The objective of this paper is to evaluate a solar trigeneration system under different criteria in order to make clear that there are numerous factors which have to be taken into consideration in the trigeneration system design. The examined system consists of parabolic trough solar collectors, a storage tank, an organic Rankine cycle and an absorption heat pump. The system is evaluated using different evaluation criteria which are associated with the energy, the exergy and the financial performance of the system. Moreover, a new criterion which takes into account the building energy needs is introduced and is investigated in different scenarios. The final results of this work clearly indicate that the optimisation of the solar driven trigeneration systems is depended on the desired design conditions and goals. Abbreviations: COP, Coefficient of performance; ECO, Economizer; EES, Engineering Equation Solver; EVAP, Evaporator; ORC, Organic Rankine Cycle; PTC, Parabolic trough collector; SC, Scenario [ABSTRACT FROM AUTHOR]

Solar Photovoltaics (PV) is considered a highly competitive technology supporting the transition towards a low-carbon energy system. However, increased shares of its deployment have caused a set of mainly regulatory and financial challenges which require solutions. This paper identifies key research challenges for the further development and deployment of Solar PV, aiming to bridge the gap between expressed market needs and scientific research inquiries. The findings revealed a heterogeneous landscape of Research Priorities and Research Needs focused around the issues of renewable energy sources' variability, the impacts of curtailment, material (re-)use and module efficiency, synergies with the cooling/heating sector, quality criteria and standardisation, as well as new support schemes and business models. These findings can be taken up by academic institutions or technology associations to shape further directions for research. Finally, a list of implications to guide potential end-users involved in the field of policy and practice is provided. [ABSTRACT FROM AUTHOR]

One challenge in designing a photovoltaic (PV) system is to predict its generation, given parameters such as location, meteorological conditions, and layout. A greater challenge is to predict the generation of such a system under snow-cover condition. Publicly available snowfall data provide records for horizontal surfaces. However, the effect of snow accumulated on a tilted PV module remains unknown. Hence, irradiance is insufficient for predicting the output of PV systems having any given layout configuration. The research in this paper aims to predict the daily generation of PV systems through the development of a predictive model flexible enough to accommodate different layout configurations based on long-term monitoring data collected from 85 sites. Snow coverage loss factors are derived empirically to enhance the performance of the model. A feed-forward artificial neural network model is developed and implemented with snow adjustments (snowfall data and snow coverage loss factors). Promising results are obtained and validated. [ABSTRACT FROM AUTHOR]

Concentrated solar collectors have high efficiency. Therefore, when concentrating collectors are used for water heating application, the system yields higher efficiency. From a hot climate perspective, there is a huge potential available for low-cost solar water heating systems. With the system described in this paper, the needs of hot water in the domestic sector can be fulfilled instantly. Authors used the parabolic dish collector for instant water heating. This paper describes the effect of variation of mass flow rate on performance of the parabolic dish water heater prototype. Design of the solar parabolic dish collector consists of a novel truncated cone-shaped helical coiled receiver made up of copper at focal point. This prototype was evaluated for its performance during the month of April and May 2010. [ABSTRACT FROM AUTHOR]

This paper presents an economic analysis of stationary and dual-axis tracking photovoltaic (PV) systems installed in the US Upper Midwest in terms of life-cycle costs, payback period, internal rate of return, and the incremental cost of solar energy. The first-year performance and energy savings were experimentally found along with documented initial cost. Future PV performance, savings, and operating and maintenance costs were estimated over 25-year assumed life. Under the given assumptions and discount rates, the life-cycle savings were found to be negative. Neither system was found to have payback periods less than the assumed system life. The lifetime average incremental costs of energy generated by the stationary and dual-axis tracking systems were estimated to be $0.31 and $0.37 per kWh generated, respectively. Economic analyses of different scenarios, each having a unique set of assumptions for costs and metering, showed a potential for economic feasibility under certain conditions when compared to alternative investments with assumed yields. [ABSTRACT FROM AUTHOR]

Technological breakthroughs in renewable energy technologies (RETs) enabled them to attain grid parity thereby making them potential contenders for existing conventional resources. To examine the market participation of RETs, this paper formulates a scheduling problem accommodating energy market participation of wind- and solar-independent power producers (IPPs) treating both conventional and RETs as identical entities. Furthermore, constraints pertaining to penetration and curtailments of RETs are restructured. Additionally, an appropriate objective function for profit incurred by conventional resource IPPs through reserve market participation as a function of renewable energy curtailment is also proposed. The proposed concept is simulated with a test system comprising 10 conventional generation units in conjunction with solar photovoltaic (SPV) and wind energy generators (WEG). The simulation results indicate that renewable energy integration and its curtailment limits influence the market participation or scheduling strategies of conventional resources in both energy and reserve markets. Furthermore, load and reliability parameters are also affected. [ABSTRACT FROM AUTHOR]

In India, uniform price was assigned to renewable energy certificate (REC) irrespective of renewable energy (RE) type, technology, and location. Moreover REC price bands are higher than existing preferential tariff. There are distinct renewable purchase obligations (RPOs) specified for various RE types, whereas there is lack of efficient tools to check RPO compliance. Because of these reasons, REC market stabilisation is getting delayed. This paper proposes a method using plant performance multiplier to convert non-solar and solar REC to single equivalent REC with competitive REC pricing, which can be traded on unified REC market. The method combines solar and non-solar RPOs into a single composite RPO, to make RPO compliance and its checking simple and efficient. A sample illustration of the proposed method is given. The benefits offered by the proposed method in REC pricing, REC trading and RPO compliance are discussed. A comparative economic analysis of present and proposed method is reported. [ABSTRACT FROM PUBLISHER]

Solar energy is the primary resource for all biological, chemical and physical processes. The amount of global solar radiation is an important parameter for solar energy applications. It is common to estimate a monthly average of daily global solar radiation using different regression models. These models in turn exploit the correlation between solar radiation and various atmospheric factors. These factors are commonly derived from meteorological, geographical and climatological data that are readily available for majority of weather stations across the world. In this paper, a novel regression model that can predict location-independent daily global solar radiation is presented. The proposed exponential quadratic model captures the correlation between measured global solar radiation values, sunshine hour and Air Pollution Index for Indian cities. In addition to this, an extended study of several other regression models (e.g. linear, quadratic, exp.-linear and exp.-quadratic) is also presented. This analysis with real data from Indian cities suggests that air pollution is a more significant factor than location when predicting solar radiation. Finally, the model parameters (regression coefficients) for each model are listed out. Additionally, the generalised model equation for the best performing model is also presented. [ABSTRACT FROM PUBLISHER]

The amount of solar radiation received on the earth's surface is known to be highly influenced by the weather conditions and the geography of a particular area. This paper presents some results of an investigation that was carried out to find the effects of weather patterns on the solar radiation in Brunei Darussalam, a small country that experiences equatorial climate due to its geographical location. Weather data were collected at a suitable location in the University Brunei Darussalam (UBD) and were compared with the available data provided by the Brunei Darussalam Meteorological Services (BDMS). It has been found that the solar radiation is directly proportional to the atmospheric temperature while it is inversely proportional to the relative humidity. It has also been found that wind speed has little influence on solar radiation. Functional relationships between the solar radiation and the atmospheric temperature, and between the solar radiation and the relative humidity have also been developed from the BDMS weather data. Finally, an artificial neural network (ANN) model has been developed for training and testing the solar radiation data with the inputs of temperature and relative humidity, and a coefficient of determination of around 99% was achieved. This set of data containing all the aforementioned results may serve as a guideline on the solar radiation pattern in the geographical areas around the equator. [ABSTRACT FROM AUTHOR]

Most of the studies conducted on solar energy assessment and solar system siting focus on flat terrains that are usually difficult and expensive to acquire in urban areas. This paper investigates the possibility of using inclined terrains for siting photovoltaic (PV) power plants surrounding urban area. Both analytical analysis and simulations are carried out in order to analyse and validate the effectiveness and benefits of the use of inclined land for PV siting. Geographical information system and numerical weather prediction were used to implement the suggested original approach and to select suitable inclined terrains for the PV system installation and to calculate the total generation potential for energy production. Muscat, the capital of Oman, was selected as a reference for the implementation of this approach. [ABSTRACT FROM PUBLISHER]

Drying of agricultural food products is one of the most attractive and cost-effective applications of solar energy. The solar dryer is less reliable due to the intermittent nature of solar energy. This shortcoming can be overcome to some extent by storing solar energy. Information on sensible and latent heat storage materials and systems is spread widely in the literature. In this paper, we try to gather information about the previous and current research works in the field of thermal energy storage technology for solar air heater and dryer. The relative studies are classified on the basis of the type of storage material used in solar dryers, i.e. phase change material (PCM), rock, water, etc. Several designs of solar dryers with different heat storage materials were proposed by researchers. Recent studies focused on PCMs such as Paraffin and salt hydrate, due to their high heat storage capacity per unit volume. [ABSTRACT FROM AUTHOR]

This paper examines the role of renewable energy sources (RES), especially the sun, as a potential solution for solar radiation management concerns. It states how photovoltaic (PV), especially low-cost PV and other thin film technology, can be applied and what impact and share they can have on the European market – using the Cyprus market as an example of strategic implementation. The Energy Service of the Ministry of Energy, Commerce, Industry and Tourism currently reports a 7.5% share (as at end of 2012) of RES in overall final energy consumption and suggests ways in which that share can increase. In the near future, PVs will be the most significant electricity source if the cost per kWh produced is further reduced, as was proven recently during the award procedures for PV systems. [ABSTRACT FROM AUTHOR]

Energy supplies particularly in remote and far-flung rural areas are in pathetic situation. Leave aside other needs, most of the rural communities still use wood as a source of energy for cooking. Burning of wood is not only an inefficient method, but also hazardousness for the person working on the stove. People have been working for cleaner and efficient means of cooking for decades. Solar cooker- and biogas-based cook stoves are two of the successfully implemented technologies in this area. Although solar cooker requires no maintenance, the initial investment is quite high for a cluster of villages. In addition to this, the intermittency involved in solar energy makes this an unreliable source. In this paper, a cluster of villages of Narendra Nagar block of Tehri Garhwal district of Uttarakhand, India, has been studied in terms of their thermal requirements. The potential of solar energy and biomass energy has been estimated. An integrated solar–biogas system has been proposed to satisfy this cooking demand. To obtain the optimal sizes of solar cooker and biogas generator, MATLAB codes have been developed. It was found that this system is more economical and much reliable than the other two cases. [ABSTRACT FROM PUBLISHER]

This paper analyses the hybrid solar and pump hydroelectric power plant and its hydrological and hydro-energetic characteristics and indicators. The sustainability of the system is based on stable water and energy budget. The key theoretical relationship for solar-hydro system, between electric powers of solar generator, artificial water resources, and storage is set, including relevant formulas and indicators. Artificial rain, flow, and hydro-energy potential, as indicators of the hybrid power plant, have been derived, as well as hydro-energy production characteristics. The developed and presented hydrological and hydro-energetic indicators are information for hybrid energy system analyses and design. The proposed indicators have been applied on two different climate areas, as paradigms of Continental and Mediterranean climate, using a photovoltaic and a solar thermal generator. The obtained results prove the correctness and usefulness of the proposed indicators for hybrid energy system analysis and development. [ABSTRACT FROM PUBLISHER]

Combined solar heating is an emerging technology that offers the potential for realising more efficient use of solar thermal energy in order to cover space heating and domestic hot-water loads. This paper is focused on small-scale applications of single-family residential dwellings in Greece. A system-level model was developed and validated. The model was exercised to evaluate strategies for optimal design and operation of solar combisystems (SCSs), using a range of performance criteria as objective functions for optimisation. The effect of SCS design and operating variables on steady-state system performance has been investigated. System design and operation optimisation has been performed through the integration and synthesis of system-level modelling with system optimal design, optimisation, and annual simulation studies to provide a comprehensive assessment. [ABSTRACT FROM PUBLISHER]

This paper presents a transformer-less single-stage grid-connected solar photovoltaic (PV) system with active reactive power control. In the absence of active input power, grid-tied voltage source converter (VSC) is operated in the reactive power generation mode, which powers control circuitry and maintains regulated DC voltage. Control scheme has been implemented so that the grid-connected converter continuously serves local load. A data-based maximum power point tracking (MPPT) has been implemented at maximum power which performs power quality control by reducing total harmonic distortion (THD) in grid-injected current under varying environmental conditions. Standards (IEEE-519/1547) stipulates that current with THD greater than 5% cannot be injected into the grid by any distributed generation (DG) source. MPPT tracks actual variable DC link voltage while deriving maximum power from PV array and maintains DC link voltage constant by changing the converter modulation index. Simulation results with the PV model and MPPT technique validations demonstrate effectiveness of the proposed system. [ABSTRACT FROM PUBLISHER]