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The prediction of global solar radiation for the regions is of great importance in terms of giving directions of solar energy conversion systems (design, modeling, and operation), selection of proper regions, and even future investment policies of the decision-makers. With this viewpoint, the objective of this paper is to predict daily global solar radiation data of four provinces (Kırklareli, Tokat, Nevşehir and Karaman) which have different solar radiation distribution in Turkey. In the study, four different machine learning algorithms (support vector machine (SVM), artificial neural network (ANN), kernel and nearest-neighbor (k-NN), and deep learning (DL)) are used. In the training of these algorithms, daily minimum and maximum ambient temperature, cloud cover, daily extraterrestrial solar radiation, day length and solar radiation of these provinces are used. The data is supplied from the Turkish State Meteorological Service and cover the last two years (01.01.2018–31.12.2019). To decide on the success of these algorithms, seven different statistical metrics (R2, RMSE, rRMSE, MBE, MABE, t-stat, and MAPE) are discussed in the study. The results shows that R2, MABE, and RMSE values of all algorithms are ranging from 0.855 to 0.936, from 1.870 to 2.328 MJ/m2, from 2.273 to 2.820 MJ/m2, respectively. At all cases, k-NN exhibited the worst result in terms of R2, RMSE, and MABE metrics. Of all the models, DL was the only model that exceeded the t-critic value. In conclusion, the present paper is reporting that all machine learning algorithms tested in this study can be used in the prediction of daily global solar radiation data with a high accuracy; however, the ANN algorithm is the best fitting algorithm among all algorithms. Then it is followed by DL, SVM and k-NN, respectively. • Comparison of four machine learning algorithms in the prediction of daily global solar radiation. • Discussion of the performance success of the algorithms with seven metrics. • Different regions come different algorithms to the fore in terms of prediction success. • ANN is generally presenting better prediction results in comparison with those of DL, SVM, and k-NN. • k-NN algorithm is giving the worst prediction results for almost all metrics. [ABSTRACT FROM AUTHOR]

According to the Vision 2023 agenda, the Turkish government plans to produce 30% of Turkey's electricity demand from renewable energy sources in 2023. This means hydroelectric, wind and solar energy capacities would increase to 36,000 MW, 20,000 MW and 3000 MW, respectively. Increased hydroelectric capacity would indeed benefit stability and flexibility of the existing energy infrastructure. However, increased wind and solar capacity could bring intermittency problems due to nature of these energy sources. Recently, pumped hydroelectric energy storage (PHES) has become a hot topic in Turkey. And, its potential applications via synergistic utilisation with wind and solar energy to solve the aforementioned intermittency problems is being discussed. Yet, detailed information in the literature about PHES in Turkey is scarce. Therefore, this paper was intended to provide this crucial information. Detailed analysis showed even if all obstacles are overcome and all potential PHES capacity is used PHES could only provide a storage capacity worth equivalent to 0.6-0.8% of Turkey's annual electricity demand in 2023. It is estimated that the overnight capital cost required to develop this PHES potential is between 3.6 and 6.5 billion US$. Even so, there would be serious economic risks of PHES plants. Because, PHES systems are currently net consumers of energy. Current study also showed that instead of focusing on PHES, flexibility of Turkish electricity market could be sustained by diversifying energy sources and increasing nuclear energy capacity. It is estimated that an additional 490 MW of nuclear capacity could provide the same potential PHES capacity. By this way, intermittency problems associated with increased share of solar and wind energy can be easily tackled without imperilling the Vision 2023 energy targets. [ABSTRACT FROM AUTHOR]

Energy production in a safe and hazard free manner is one of the world׳s greatest concern. Since the inception of Kyoto Protocol, which was adopted in 1997 and entered into force in February 2005, countries have started to adopt different measures for emission reduction such as electricity generation from renewable energy sources; as the source is free from green house gas (GHG) or CO 2 emission. Legislations and financial incentives have been provided by some governments for encouragement and ensuring good returns to the investors in renewable energy sector. This paper analyzes how a 500 kWp solar photovoltaic (PV) system for electricity generation contributes significantly in the GHG emission reduction and also the potential impact of introducing CO 2 emission reduction cost in the solar PV electricity generation. The result shows that the emission reduction is of the order of hundreds of tons of CO 2 and CO 2 emission reduction cost has a positive impact on the cumulative cash flow of the system. [ABSTRACT FROM AUTHOR]

This paper presents an energy performance analysis of three different photovoltaic (PV) modules technologies under İzmit, Kocaeli weather conditions in Northwest of Turkey. Some comparative analyzes were conducted for showing solar energy potential of İzmit, Kocaeli. For this purpose, by using crystalline (c-Si), multi crystalline (mc-Si) and cadmium–telluride (Cd–Te) modules, three on-grid photovoltaic power systems (PPS) were installed on the rooftop of the Engineering Faculty at Kocaeli University. These PPSs were monitored from October, 2013 to December, 2014. In order to determine the energy performances of PV modules and PPSs, normalized energy of systems, performance ratios (PRs), mean array efficiencies (MAEs) and capacity factors (CFs) were calculated. The results show that due to the low dependency on weather changes, MAE of Cd–Te arrays result in higher value than that of the other arrays. Changes in PRs of c-Si and mc-Si arrays are lower than Cd–Te arrays within the measurement period and mean values of PRs are 83.8%, 82.05% and 89.76% for mc-Si, c-Si and Cd–Te arrays, respectively. Since Cd–Te array has the highest CF during all months, Cd–Te array can be accepted as more reliable array under İzmit climatic condition. On the other hand, one of the outcomes of this study is to reveal the solar energy potential of İzmit by on-site measurements. So, it is shown that contrary to measurement taken between 1985 and 2006 from 156 stations by General Directorate of Renewable Energy (GDRE) and Turkish State Meteorological Service (DMI), İzmit has more solar energy potential by rate of 23.79%. [ABSTRACT FROM AUTHOR]

Abstract: Thermal energy storage (TES) is regarded as among the most feasible environmentally friendly solutions for saving energy. R&D activities for heating and cooling of buildings lead to the development of various technology types. This paper attempts to give an overview of the energy situation, solar energy potential, TES concepts and technologies used in solar applications around the world with the emphasis on two Mediterranean countries, Turkey and Slovenia. Energy savings and CO2 emission reduction potential when TES is used in various solar applications of buildings are also discussed. [Copyright &y& Elsevier]

Abstract: Turkey is a rich country from the point of variety and potential of renewable energy resources. Hydros, winds, biomass, solar and geothermal are important renewable and environmentally friendly sources for energy in Turkey. Turkey produces large amount of hydropower with a total gross hydropower potential of 433TWh/yr, which is equal to 13.8% of the total hydropower potential of Europe. Technically useable potential is 216TWh/yr and economic potential is 140TWh/yr. The main aim of the present study is to investigate hydropower potential of Turkey and small hydropower plants in Eastern Black Sea Region for sustainable energy development in Turkey. The geography of Turkey especially, Eastern Black Sea Region supports and suitable the development of the small hydro plants to increase the energy generation and utilization of available water sources in Turkey. Besides, the paper deals with hydropower policies to meet ever increasing energy demand for sustainable development of Turkey. [Copyright &y& Elsevier]

Abstract: This paper deals with finding the optimum tilt angle of solar panels for solar energy applications. The optimization of tilt angles was performed using solar radiation data measured for eight big provinces in Turkey. The optimum angle for tilted surfaces varying from 0° to 90° in steps of 1° was calculated by searching for the values of which the daily total solar radiation was at a maximum for a specific period. It was found that the optimum tilt angle changed between 0° and 65° throughout the year in Turkey. It was seen that the optimum tilt angle reached a minimum of 0° in June and July and, the monthly average daily total radiation at this angle was generally at a maximum. In addition, the optimum tilt angle increased during the winter months and reached a maximum in December in all provinces. Likewise, general correlations were developed to estimate the optimum tilt angle of solar collectors used in Turkey and their accuracies were compared on the basis of statistical error tests of Mean Bias Error (MBE), Root Mean Square Error (RMSE), t-statistic (t-stat) and correlation coefficient (r). [Copyright &y& Elsevier]

Abstract: The Republic of Turkey, located in Southeastern Europe and Southwestern Asia (that portion of Turkey west of the Bosporus is geographically part of Europe). Nowadays, Turkey with its young population and growing energy demand per person, its fast growing urbanization, and its economic development, has been one of the fast growing electrical energy markets of the world for the last two decades. Unfortunately, Turkey''s energy is largely dependent on foreign countries and the country''s energy is imported spending billions of dollars each year. On the other hand, the effects on global and environmental air quality of pollutants released into the atmosphere from fossil fuels in electric power plants provide strong arguments for the development of renewable energy resources. Solar energy is one of the best available among renewable energy sources. There are possess many advantages of solar energy such as relativity, viability, silent, non-polluting, little maintenance, suitable for remote site application, not require any fuel and independent from electricity network. Turkey has advanced a great deal in the generation of electricity from solar energy because of much higher solar energy potential than lots of developed countries on solar energy applications. This study is taken into account that overview of the photovoltaic technology status and perspective in Turkey and the contains of photovoltaic power systems utilization and potential status in the world, energy consumption and demand in Turkey, geographic description of the solar energy in Turkey, PV industry current and potential status in Turkey, solar energy legislation framework in Turkey, R&D status of photovoltaic industry in Turkey, future strategy of PV industry in Turkey, current and future status photovoltaic power systems economics in the world. Also, this paper on the basis of this subjects is analyzed the SWOT of Turkey''s photovoltaic industry, its advantages, weaknesses, opportunities and threats. [Copyright &y& Elsevier]

Abstract: Limited fossil resources and severe environmental problems require new sustainable electricity generation options, which utilize renewable energies and are economical in the meantime. Concentrating solar power (CSP) generation is a proven renewable energy technology and has the potential to become cost-effective in the future, for it produces electricity from the solar radiation. In Turkey, the electricity demand is rapidly increasing, while the solar resources and large wasteland areas are widely available in the western and southeastern part of Turkey. To change the energy-intensive and environment-burdensome economical development way, Turkish government supports the development of this technology strongly. These factors altogether make Turkey a suitable country for utilizing CSP technology. In this paper, the potential of CSP in Turkey was studied and strategies to promote development of this technology were given. [Copyright &y& Elsevier]

Abstract: The most important renewable sources are hydropower, biomass, geothermal, solar and wind. Turkey''s geographical location has several advantages for extensive use of most of these renewable energy sources. In recently, electricity has demand increased significantly; it is the fastest growing end-use of energy. Therefore, technical, economic and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix. In the world, particularly in the developing countries renewable energy resources appear to be one of the most efficient and effective solutions for sustainable energy development in Turkey. Turkey''s geographical location has several advantages for extensive use of most of the renewable energy sources. This paper deals with policies to meet increasing energy and electricity demand for sustainable energy development in Turkey. Turkey has a total gross hydropower potential of 433GWh/year, but only 125GWh/year of the total hydroelectric potential of Turkey can be economically used. [Copyright &y& Elsevier]

Abstract: Decentralized wind, hydropower, biogas and biomass, geothermal, solar thermal and solar electricity energy systems are the most commonly found renewable energy technologies promoted for rural energy supply within sustainable developments programs. They are, therefore, seen to have a central place in the practice of sustainable development and in allowing less development countries to bypass the environmentally damaging fossil fuel intensive paths made by industrialized countries. On the political front, many less development countries are critical of pressure on them to adopt environmental energy technologies. Turkey is situated the meeting point of three continents (Asia, Europe and Africa) and stands as a bridge between Asia and Europe. The country is located in southeastern Europe and southwestern Asia. As Turkey’s economy has expanded in recent years, the consumption of primary energy has increased. Presently in order to increase the energy production from domestic energy resources, decrease the use of fossil fuels as well as reduce of green house gas emissions different renewable energy sources are used for energy production in Turkey. The share of energy production from renewable energy sources has increased during the last 10 years. Turkey must import most of the energy to meet her needs. Turkey also has a large potential for renewable energies. The lack of knowledge about renewable energy technologies by most policy-makers, potential consumers, and energy firm managers has played against renewable energy developments. The paper presents renewable energy used in Turkey and Europe Union and evaluation of the market conditions and barriers of renewable energy use in Turkey. [Copyright &y& Elsevier]