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Unit Commitment (UC) requires the optimization of the operation of generation units with varying loads, at every hour, under different technical and environmental constraints. Many solution techniques were developed for the UC problem, and the researchers are still working on improving the efficiency of these techniques. Particle swarm optimization (PSO) is an effective and efficient technique used for solving the UC problems, and it has gotten a considerable amount of attention in recent years. This study provides a state-of-the-art literature review on UC studies utilizing PSO or PSO-variant algorithms, by focusing on research articles published in the last decade. In this study, these algorithms/methods, objectives, constraints are reviewed, with focus on the UC problems that include at least one of the wind and solar technologies, along with thermal unit(s). Although, conventional PSO is one of the most effective techniques used in solving UC problem, other methods were also developed in literature to improve the convergence. In this study, these methods are grouped as extended PSO, modified PSO, and PSO with other techniques. This study shows that PSO with other techniques are utilized more than any other methods. In terms of constraints, it was observed that there are only few studies that considered Transmission Line (TL), Fuel (F), Emission (E), Storage (St) and Crew (Cr) constraints, while Power Balance (PB), Generation limit (GL), Unit minimum Up or Down Time (U/DT), Ramp Up or Ramp Down Time (R-U/DT) and system Spinning Reserve (SR) were the most utilized constraints in UC problems considering wind/solar as a renewable source. In addition, most of the studies are based on a single objective function (cost minimization) and, few of them are multi-objective (cost and emission minimization) based studies.

Due to environmental and economic drawbacks of fossil fuels, global renewable energy (RE) capacity has increased significantly over the last decade. Solar photovoltaic (PV) is one of the fastest-growing RE technologies. Selecting an appropriate site is one of the most critical steps in utility-scale solar PV planning. This paper aims at proposing a rational multi-criteria decision-making (MCDM) approach based on the Brown&ndash, Gibson model for optimal site selection for utility-scale solar PV projects. The proposed model considers the project&rsquo, s net present value (NPV) along with seven suitability factors and six critical (constraint) factors. The RETScreen software was applied in calculating the NPV, the simple payback period and the carbon emission savings of the project at each alternative site. The weights of the suitability factors were determined using the analytical hierarchy process. Applied to the case study of finding the best location for a 5 MW solar PV project in northern Cameroon, the optimization results showed that Mokolo was the optimal location. The sensitivity analysis results revealed that the rankings of alternative sites based on the project&rsquo, s NPV and the proposed model are not consistent. Compared to the traditional MCDM approaches, the proposed model provides decision-makers with a more practical thinking method in the optimal location process of utility-scale solar projects.

The objective of this work is to examine and compare the techno-economic and environmental feasibility of 40MW photovoltaic (PV) power plant and 40MW parabolic trough (PT) power plant to be installed in two different cities, namely Nicosia and Famagusta in Turkish Republic of Northern Cyprus (TRNC). Long term solar radiation and sunshine data for Nicosia and Famagusta are considered and analysed to assess the distribution of solar radiation, sunshine duration, and air temperature. In addition, these two different technologies with same rated power of 40MW will be compared with the performance of the proposed Solar Power Plant at Bari, Italy. The project viability analysis is performed using System Advisor Model (SAM) through Annual Energy Production and economic parameters for both cities. It is found that for the two cities; Nicosia and Famagusta, considered through this study, the PT plants produce more energy than PV plant. It is also observed that installation of the PT system near an existing steam turbine power plant will make the investment more feasible if the steam produced by the PT system is used to run the steam turbine power plant. The high temperatures that are used to produce steam for the turbines in the PT plant system can be supplemented with a secondary plant based on natural gas or other biofuels and can be used as backup. Although the initial investment of PT plant is higher, it has higher economic return and occupies smaller area compared to PV plant of the same capacity.

In this study, a solar assisted multi-generation system is presented. The exergy and energy performance analyses are the objective of this research. The multi-generation system consists of two Rankine cycles, two absorption cycles and a hot water tank. Solar parabolic trough collectors are used to generate thermal energy from the Sun which in turn is used to power the system. The multi-generation system achieves an energy and exergy efficiency of 77% and 49%, respectively without solar input. Considering the solar PTC, the efficiencies respectively are 57% for energy and 40% for exergy. The COPs for the absorption cycle and other findings from the study are presented in details in the full paper. Exergy destruction in major components is calculated and parametric studies are done to check the performance of the system under varying global solar irradiance conditions.

We propose a method for residential end-use load analysis in developing countries. The times of use of home appliances were established by conducting face-to-face surveys, from which typical hourly load curves are obtained. For N. Cyprus, where the winter peak is the critical load, electrical heating of water and space is the dominant activity. DSM measures can reduce the peak by approximately 53 MW at the expense of US$12 million. A capital investment of $100 million for a new power plant may be deferred for 20 years.