Solar Photovoltaic Facilities Research Articles

Drivers and barriers to public acceptance of future energy sources and grid expansion in the United States

With the coming of the 21st century in the U.S., reliance on fossil fuels, in particular coal, decreased while renewable energy sources increased their contribution to the U.S. energy portfolio. The factors behind this emerging trend toward a decreased reliance on coal are many, including economic as well as policy goals. Nationally, support is strong for the general transition to renewable energy, but this support can decline at the local level particularly if renewable energy is perceived as have negative local economic impact, impeding implementation. However, some look at this as part of a transition to a new economic power structure. Due to a lack of research on identifying public preferences for energy production in the United States, the authors conducted a national survey to identify drivers and barriers of acceptance of different types of electrical energy production. Results show that nationally, most Americans support decarbonization of the energy sector, especially if wind and solar photovoltaic facilities are located at least 5 miles (8 km) from their home. This is also supported by strong preference for an energy mix containing a larger percentage of energy produced by renewable energy sources. Environmental sustainability, economic viability, and social acceptance were of roughly equal importance in pairwise comparison of policy objectives. Results also demonstrate the importance of analyzing socio-demographic characteristic's role regarding acceptance of renewable energy sources. The information is useful for policy makers to better implement renewable energy development and improve acceptance of such technologies at the local level.

Digital elevation model-based convolutional neural network modeling for searching of high solar energy regions

The prediction of potential solar energy at candidate sites plays a key role in the search for high solar energy regions to accommodate solar photovoltaic facilities. However, the estimation of solar irradiation can be inaccurate when site conditions are not similar to the ones at observation stations. In particular, regional effects caused by adjacent terrains have rarely been modeled in the estimation process. This study thus presents a digital elevation map-based convolutional neural network modeling method for the prediction of annual solar irradiation under clear-sky conditions. Using map data as an input, the sole impact of neighboring topography on available solar energy can be understood at a large scale. Specifically, with elevation maps and corresponding solar irradiation maps, the mean of solar irradiation values for each map is calculated. This mean value is then used as an output to identify the non-linear and hidden relationship between such values and the input maps in training processes. The proposed network model uses terrain map datasets and hence enables the recognition and learning of complex topographic features and patterns in the datasets. As a result, the network model has a mean absolute percent error of 0.470% for testing datasets. This implies that the topographic patterns on a large scale may coincide with variations of available solar irradiation prior to the effects of weather. Thus, the integration of raster map data with solar energy prediction has emerged to systematically learn the terrain patterns in order to predict the annual amount of solar irradiation in a region of interest. This approach can aid the determination of suitable locations for the installation of solar panels.

Ensemble models for solar power forecasting—a weather classification approach

Solar power integration has shown a significant growth in many power systems during the last decade. The intermittent nature of solar irradiance tends to vary the amount of solar power in the system and an accurate solar power forecasting method can be used to tackle this in power system planning and operation. In this paper, authors have proposed a generalized ensemble model integrating deep learning techniques to generate accurate solar power forecasts for 21 solar photovoltaic facilities located in Germany. Most important weather parameters for solar power generation are selected through a feature selection process. In addition, a weather classification approach is used to cluster the dataset and for each cluster, a separate ensemble algorithm is assigned. Finally, considering the prediction errors in each cluster, a novel ensemble model is developed. The proposed models are evaluated using root mean square error and results are compared with single machine learning techniques and available forecasting models in the literature. Compared to deep belief network, support vector regression and random forest regression models, the proposed ensemble model with cloud classification reduces RMSE error by 10.49%, 7.78%, and 7.95% respectively. Results show that the weather classification approach reduces the forecasting error by a considerable margin and the proposed ensemble model provides a better forecasting accuracy than single machine learning methods.

Energy storage needs for an Australian national electricity market grid without combustion fuels

AbstractThe opportunity to achieve a wind and solar energy only Australian national electricity market (NEM) grid is linked to the development of massive energy storage systems. Photovoltaic solar energy is unavailable nighttime and reduced when it is cloudy or raining. Wind energy also drops some days to zero, with similarly large fluctuations between maximum and minimum energy supplies. This fundamental aspect is being ignored when only trying to increase the nominal capacity of wind energy and solar photovoltaic facilities. The need for a massive energy storage system to properly use this increased capacity is highlighted by the high‐frequency energy generation data by source that we show for the NEM that is covering most of South Australia, Victoria, Tasmania, New South Wales, and Queensland, with the only exception of Western Australia and the Northern Territory. This analysis highlights the present energy storage needs for a NEM wind and solar only. The nominal capacity of wind and solar, and the energy storage, that is supposed to increase up to unbelievably high values, to only cover the electricity production, is due to increase even more, to cover the TPES demand, and not only the electricity demand, of a country without combustion fuels.

Hydrogen as an energy vector to optimize the energy exploitation of a self-consumption solar photovoltaic facility in a dwelling house

Solar photovoltaic (PV) plants coupled with storage for domestic self-consumption purposes seem to be a promising technology in the next years, as PV costs have decreased significantly, and national regulations in many countries promote their installation in order to relax the energy requirements of power distribution grids. However, electrochemical storage systems are still unaffordable for many domestic users and, thus, the advantages of self-consumption PV systems are reduced. Thus, in this work the adoption of hydrogen systems as energy vectors between a PV plant and the energy user is proposed. As a preliminary study, in this work the design of a PV and hydrogen-production self-consumption plant for a single dwelling is described. Then, a technical and economic feasibility study conducted by modeling the facility within the Homer Energy Pro energy systems analysis tool is reported. The proposed system will be able to provide back not only electrical energy but also thermal energy through a fuel cell or refined water, covering the fundamental needs of the householders (electricity, heat or cooling and water). Results show that, although the proposed system effectively increases the energy local use of the PV production and reduces significantly the energy injections or demands into/from the power grid, avoiding power grid congestions and increasing the nano-grid resilience, operation and maintenance costs may reduce its economic attractiveness for a single dwelling.

Integrating wind, photovoltaic, and large hydropower during the reservoir refilling period

Hydropower facilities are an ideal solution to complement the intermittent production of energy from wind and solar photovoltaic facilities in electric power systems. However, adding this task to the multiple diverse duties of a reservoir (e.g., flood mitigation, water supply, and power generation) poses a challenge related to pursuing multiple and sometimes conflicting objectives. This study proposes an approach for integrating hydro, wind, and photovoltaic power during a reservoir’s refill period. Specifically, this approach simultaneously minimizes the fluctuation in the combined power output of these three resources and maximizes their combined power generation while adhering to the target reservoir’s water levels. The proposed approach uses a multiobjective optimization model that prescribes a day-ahead optimal hourly operation for a hydropower facility in terms of spilled water, water stored in the reservoir, and water used for power generation, while meeting a daily target to refill the reservoir. The prescribed scheduling is then used as the input into a model that simulates the actual operations of the power system. This study focuses on a hydro-wind-photovoltaic system located in southwestern China, where the peak power generating capacity of the hydropower facility is ten percent larger than the combined installed capacity of the wind and solar power. The results show that by using the proposed model, the hydropower facility effectively smooths the fluctuations in the combined power output caused by variable wind and photovoltaic power and concurrently meets the reservoir replenishing targets under dry, moderate, or wet hydrologic scenarios. Furthermore, the trade-offs between power generation maximization and power fluctuation reduction were found to depend on two conditions: whether the reservoir is full, and whether the turbine is generating electricity at its maximum capacity. The hydro-wind-photovoltaic integration is more cost-effective when the reservoir is not full and the turbines are not generating electricity at their maximum capacity. When the reservoir is full, hydropower still has the ability to balance the wind and photovoltaic power without curtailment but tends to result in water spillage (22–402 m3/s) and reductions in electricity generation (0.1–11.4 GWh per day). The proposed method for scheduling operations allows hydropower facilities to complement wind and photovoltaic power output, while meeting the target water levels during the refill period.

A Study for Planning Optimal Location of Solar Photovoltaic Facilities using GIS

A Study for Planning Optimal Location of Solar Photovoltaic Facilities using GIS

Dispatchability of solar photovoltaics from thermochemical energy storage

Solar photovoltaic plants are today a competitive alternative to power plants based on fossil fuels. Cost reduction in photovoltaics modules, scalability and ease of installation of these plants are enabling a rapid worldwide expansion of the technology. Nevertheless, dispatchability still remains as the major challenge to overcome due the intrinsic variability of solar energy. Most of the current solar photovoltaic facilities at large scale lack energy storage while those with storage systems rely on expensive batteries. Batteries are based on elements such as nickel, lithium or cadmium whose scarcity hinder their sustainability for storing energy in the large scale. This manuscript presents a novel concept to integrate thermochemical energy storage in photovoltaic plants. Furthermore, the concept is also directly adaptable to wind power plants to store surplus energy. The paper analyses the suitability of the Calcium-Looping process as thermochemical energy storage system in solar photovoltaics plants. The system works as follows: part of the power produced in the solar plant provides electricity to the grid while the rest is used to supply heat for calcination of calcium carbonate. After calcination, the products of the reaction – calcium oxide and carbon dioxide- are stored separately. When power production is required, the stored products are brought together in a carbonation reactor wherein the exothermic reaction releases energy for power production. The overall system is simulated to estimate the process behaviour and results show that storage efficiencies of ∼40% can be achieved. Moreover, an economic analysis is developed to compare the proposed system with batteries. Due to the low price of natural calcium oxide precursors, such as limestone, and the expected longer lifetime of equipment as compared to batteries, the Calcium-Looping process can be considered as a potential alternative for improving dispatchability in solar photovoltaic plants.

How should government and users share the investment costs and benefits of a solar PV power generation project in China?

Under the circumstances of global carbon emissions reduction, it has become a trend to promote the adoption of clean energies, such as solar energy. With the increasing maturity of photovoltaic (PV) technology, household-type distributed solar PV power generation projects are increasingly popular in China. Nevertheless, compared with conventional power generation, the initial cost of a solar PV project remains relatively high. Therefore, to mobilize the incentives of the general public, there is an urgent need for studies on how to share the costs and benefits of a solar PV power generation project between the government and users. By adopting the Shapley Game methodology, this paper has conducted a theoretical analysis of the cost-sharing among the central government, local government, and users and has built an investment cost-sharing model (Ci′=P(i)−Vs(i)−Vri,i=1,2,3), which is able to coordinate the benefit of all three stakeholders. This is followed by a case study. The results show that, under China's central government subsidy of 0.42 yuan per kWh, the best strategy for the local government to encourage the public to install solar PV facilities is to provide a one-off compensation equal to 30% of the initial investment. Finally, this paper proposes relevant policy recommendations to promote the development of solar PV power generation for emissions reduction in China.

Transient analysis and simulation of a grid-integrated large-scale photovoltaic (PV) energy system

Photovoltaic (PV) power generation is the fastest growing technology in the distributed generation sector. In addition to integrating renewable energies, current grid is required to be reliable, stable, and of high-quality power. The large-scale integration of PV power into the grid is bound up with problems of the safe operation of the grid, bringing new challenges to the GCC (Gulf Cooperation Council) system. The objective of this paper was to study and analyze the integration of large-scale PV facilities into the GCC power grid and to address their energy security and environmental challenges. A new simulation model was developed to analyze and investigate the impact of integrating large-scale solar PV facilities into the distribution power grid and to carry out transient stability analysis.

Mean flow through utility scale solar facilities and preliminary insights on dust impacts

Deposition of dust on solar collectors has the potential to be a costly part of utility-scale solar energy production operation and maintenance. Large facilities are frequently located in arid regions with dusty soils. The orientation of solar fields with respect to the wind may affect how vulnerable or protected the soil surface is from the erosive power of the wind. Field measurements of wind flow through a utility-scale solar photovoltaic facility are presented. Multiple measurements of wind speed by spinning cup anemometer and wind direction by rotating vane were collected between consecutive rows of panels at two heights above the ground. This dataset provides preliminary insight into the mean flow field for a nominally two-dimensional solar array. A better understanding of non-steady flow components, turbulence, and conditions for the initiation of sand transport is needed for accurate prediction of dust impacts of such facilities.

An assessment of photovoltaic potential in shopping centres

The solar photovoltaic is a renewable energy source which allows nowadays, in many places, the generation of electricity at a cost comparable with the conventional thermal generation methods. However, ending 2014, with a worldwide power capacity installed of 177 GW, the integration level in the electricity generation mix was still far from the targets set up for this technology in the global warming mitigation strategies.Technical, financial and regulatory barriers slow down a massive penetration of photovoltaic generation facilities, hence practical and innovative measures are necessary to facilitate a wider deployment.The building integration of solar photovoltaic facilities offers an efficient solution because the electricity is generated near the consumption point and gives a new economic value to roofs and facades. In this paper we develop a scientist methodology for determining the potential in shopping centres, to establish that, in terms of photovoltaic integration, these present important competitive advantages over other alternatives, i.e. the residential buildings. The power capacity potential obtained making use of this methodology in the countries selected is 16,8GW, that means 10% of the worldwide capacity installed at the end of 2014, with a yearly electricity generation of 22,7TWh equivalent to 14% of the worldwide generation in 2014.

Decision-Making for Risk Management in Sustainable Renewable Energy Facilities: A Case Study in the Dominican Republic

Today, Renewable Energy Sources (RES) are a key pillar to achieving sustainable development, which is the main reason why energy projects are being carried out not only in developed countries but also in many emerging countries. Since the technical and financial risk remains a major barrier to financing renewable energy projects, several mechanisms are available to reduce risks on investment into clean energy projects. This paper discusses risk management tools in solar photovoltaic facilities based on the guide to the Project Management (PMBOK Guide). To do this, a combination of different decision-making methodologies will be carried out. These methodologies enable to not only extract the knowledge by experts but also to know the causes and effects that help to make the best decision. In order to do so, techniques to seek information (Delphi and Checklist) as well as diagram techniques such as cause and effect diagrams or Strengths Weaknesses Opportunities and Threats (SWOT) are applied. The categorization and prioritization of risks will be carried out through the Analytic Hierarchy Process (AHP). Finally, a sensitivity analysis will allow for providing consistency to the obtained results. A real case in the Dominican Republic will also be presented as case study.

Low Drop-Out Voltage Regulator as a Candidate Topology for Photovoltaic Solar Facilities

This article aims to present the design of a 4.5-V, 450-mA low drop-out (LDO) voltage linear regulator based on a two-stage cascoded operational transconductance amplifier (OTA) as error amplifier for photovoltaic solar DC-DC regulation. The aforementioned two-stage OTA is designed with cascoded current mirroring technique to boost up the output impedance. The proposed OTA has a DC gain of 101 dB under no load condition. The designed reference voltage included in the LDO regulator is provided by a band gap reference with the temperature coefficient (T?) of 0.025 mV/oC. The proposed LDO regulator has a maximum drop-out voltage of 0.5 V @ 450 mA of load current, and has the worst case power supply rejection ratio (PSRR) of [54.5 dB, 34.3 dB] @ [100 Hz, 10 kHz] in full load condition. All the proposed circuits are designed using a 0.35 µm CMOS technology. The design is checked in order to corroborate its performance for wide range of input voltage, founding that the circuit design works fine meeting all the initial specification requirements.

Comparing solar PV (photovoltaic) with coal-fired electricity production in the centralized network of South Africa

South Africa has a highly centralized network, in which almost all electricity is produced in Mpumalanga and transmitted throughout South Africa. In the case of the Western Cape, electricity has to be transmitted over 800–1370 km. This generates losses and entails high transmission costs. Investments in additional production and transmission capacity are needed to cope with the growing demand. Although there is a large potential for solar energy in South Africa, investments are lacking while large investments in new coal-fired power plants are being executed. These coal power plants do not only increase the need for heavier transmission infrastructure, but also have a higher CO2 emission level and a higher pressure on water reserves. This paper performs a more comprehensive cost-analysis between solar energy production and coal production facilities, to make a more elaborate picture of which technologies are more plausible to foresee in the growing demand of electricity. The current centralized electricity infrastructure makes the investment in large production facilities more likely. However, it should be questioned if the investment in large centralized solar parks will be more beneficial than the investments by consumers in smaller solar PV facilities on site.

Operation of TUT Solar PV Power Station Research Plant under Partial Shading Caused by Snow and Buildings

A grid connected solar photovoltaic (PV) research facility equipped with comprehensive climatic and electric measuring systems has been designed and built in the Department of Electrical Engineering of the Tampere University of Technology (TUT). The climatic measuring system is composed of an accurate weather station, solar radiation measurements, and a mesh of irradiance and PV module temperature measurements located throughout the solar PV facility. Furthermore, electrical measurements can be taken from single PV modules and strings of modules synchronized with the climatic data. All measured parameters are sampled continuously at 10 Hz with a data-acquisition system based on swappable I/O card technology and stored in a database for later analysis. The used sampling frequency was defined by thorough analyses of the PV system time dependence. Climatic and electrical measurements of the first operation year of the research facility are analyzed in this paper. Moreover, operation of PV systems under partial shading conditions caused by snow and building structures is studied by means of the measured current and power characteristics of PV modules and strings.

The prospects for cost competitive solar PV power

New solar Photovoltaic (PV) installations have grown globally at a rapid pace in recent years. We provide a comprehensive assessment of the cost competitiveness of this electric power source. Based on data available for the second half of 2011, we conclude that utility-scale PV installations are not yet cost competitive with fossil fuel power plants. In contrast, commercial-scale installations have already attained cost parity in the sense that the generating cost of power from solar PV is comparable to the retail electricity prices that commercial users pay, at least in certain parts of the U.S. This conclusion is shown to depend crucially on both the current federal tax subsidies for solar power and an ideal geographic location for the solar installation. Projecting recent industry trends into the future, we estimate that utility-scale solar PV facilities are on track to become cost competitive by the end of this decade. Furthermore, commercial-scale installations could reach “grid parity” in about ten years, if the current federal tax incentives for solar power were to expire at that point.

The Prospects for Cost Competitive Solar PV Power

New solar Photovoltaic (PV) installations have grown globally at a rapid pace in recent years. We provide a comprehensive assessment of the cost competitiveness of this electric power source. Based on data available for the second half of 2011, we conclude that utility-scale PV installations are not yet cost competitive with fossil fuel power plants. In contrast, commercial-scale installations have already attained cost parity in the sense that the generating cost of power from solar PV is comparable to the retail electricity prices that commercial users pay, at least in certain parts of the U.S. This conclusion is shown to depend crucially on both the current federal tax subsidies for solar power and an ideal geographic location for the solar installation. Projecting recent industry trends into the future, we estimate that utility-scale solar PV facilities are on track to become cost competitive by the end of this decade. Furthermore, commercial-scale installations could reach “grid parity” in about ten years, if the current federal tax incentives for solar power were to expire at that point.

A new and inexpensive temperature-measuring system: Application to photovoltaic solar facilities

This article presents the design, construction and testing of a new and inexpensive digital sensor-based temperature-measuring system, whose principal characteristics are: precision, ease of connection, immunity to noise, remote operation and easy scaling, and all this at a very low cost. This new digital sensor-based measuring system overcomes the traditional problems of digital measuring sensors, offering characteristics similar to Pt100-based measuring systems, and therefore can be used in any installation where reliable temperature measurement is necessary. It is especially suitable for installations where cost is a deciding factor in the choice of measuring system. It presents a practical application of the developed instrumentation system for use in photovoltaic solar facilities. This new temperature-measuring system has been registered in the Spanish Patent and Trademark Office with the number P200803364.