Sustainable generation is impacted by the adoption of renewable energy, the growth of energy markets, and economic strategies. This paper offers a sustainable strategy and a technoeconomic analysis of off-grid hybrid energy systems (HES) in remote islands of Iran, including Lavan, Larak, and Failaka, utilizing PV module, wind turbine, and hydrokinetic turbines. Hourly wind speed, solar irradiation, and hydrovelocity have been implemented under load following (LF) and cycle charging (CC) dispatch strategies in order to ascertain the most appropriate systems. Lavan Island achieves the winning HES with a CC dispatch strategy, which consists of 3 hydroelectric turbines, 1 wind turbine, 349 kW of solar power, 150 kW of generator power, 316 kWh of batteries, and 287 kW of the converter. This ideal HES, which generates a consistent generation profile and reasonable net present cost (NPC) and cost of energy (COE) of M0.160$ and $0.013 kWh, respectively, can be practically attained in these areas. LF-controlled optimal solutions use less fuel than CC-based ones, leading to a higher share of renewable energy. Compared to Larak and Lavan, the CC- and LF-controlled options on Failaka Island generate cleaner electricity with emissions that are 57% and 44% lower. Regarding the ability to recoup the project’s initial investment costs, long-term energy production would be more financially viable than short-term. Short-term projects with higher financial uncertainty due to the salvage cost should use the CC method.

This study presents a combination of optimal placement and power system development with the aim of supplying electricity for Nuclear Power Plant after the trip of power plant. Power supply to the internal loads of power plant by the off-site power system is one of the main fields of research in achieving the safety Nuclear Power Plant. One of the main purposes in this article is to introduce a suitable and safe place for the construction and connection of a Nuclear Power Plant to the power system. These locations are identified by the power plants on-site loads and the average of the lowest number of relay protection after the Nuclear Power Plant trip, based on electricity considerations. Along with the optimal placement in this paper, the power system development, including the generation and transmission development in order to provide electricity with higher reliability to the Nuclear Power Plant after the trip is also presented. Monte Carlo and Latin Hypercube Sampling probabilistic methods are proposed for locating the site of a Nuclear Power Plant and algorithms of Genetic and Particle Swarm Optimization for locating and developing power generation and transmission systems. The simulation results are implemented on the IEEE RTS 24-bus system, and finally suitable locations for the construction of the Nuclear Power Plant and the generation and transmission development with the aim of feeding the power plant from the off-site power system and sufficient assurance that the reactor core does not melt after the trip, are determined.

Every year, the load growth in distribution networks causes various challenges such as voltage drop. Since some of these challenges are due to the lack of reactive power sources, these problems can be solved by installing reactive power resources such as capacitors. On the other hand, considering that the installation of capacitors in the network based on one or more hours of the study period (due to the impracticality of carrying out load flow studies in all the hours of the multi-year study period) caused to over investment in capacitors and becomes uneconomical, a solution should be provided in order to optimally allocate these resources based on all the hours of the multi-year study period. Therefore, in order to solve the problem raised and in order to rationally allocate reactive power compensation devices in distribution networks, a method based on fuzzy logic is developed in this paper to take into account the amount of network load in all hours of the study period and at the same time the execution of simulations be very short in order to solve such problems. Hence, in this paper, as the first contribution, the considered problem has been solved using the method based on standard fuzzy logic, taking into account all the hours of the study period, and then as the second contribution, the optimization of the parameters of the fuzzy membership functions has been discussed, and the proposed method has been upgraded. The simulation results showed that the developed method has sufficient efficiency and it can be used to optimally allocate capacitors in the network by considering all the hours of the study period. Also, the developed method was able to improve the objective functions to a greater extent by optimally setting the parameters of the fuzzy membership functions. Optimizing the parameters of the fuzzy membership functions made the objective function of the total costs to be improved by 0.8, 1.9 and 2.5 percent by installing one, two and three capacitors, respectively. Also, this optimization caused the objective function of voltage profile to improve by 0.4, 0.7, and 1.2 percent, respectively, by installing one, two, and three capacitors.