Moreover, wind turbines require limited land cover, compared to solar panels, and cause less landscape transformation than hydroelectric energy. Wind energy is an energy source with a decreasing levelized cost of energy (LCOE) trend and its global energy generation capacity has reached 650.8 GW as of 2019, a number expected to rise to 1000 GW by the year 2030. According to Greece’s National Energy and Climate Plan, Greece should reach 7 GW of installed wind farm capacity by 2030, compared to 3.6 GW in 2020, to meet its environmental targets.
Certainly, Climate change brings the world face-to-face with the need for carbon-free technologies, such as renewable energy sources (RESs), to meet their need for electricity.
However, increasing the proportion of RESs in the power mix creates new challenges for renewable energy production and demand. As far as wind energy is concerned, the intermittent nature of wind potential, due to its dependence on different climate conditions, makes the forecasting of wind energy very difficult and creates the need to use of wind turbines not individually but as a part of a hybrid renewable energy system (HRES). HRESs use at least one form of RES and at least one form of energy storage technology for the excess energy that cannot be used immediately.
Pumped hydro storage (PHS) is an environmentally friendly storage method and can be used in areas where topography and water availability parameters permit. About 96% of the total energy storage installed capacity (160 GW) is through PHS systems. Numerous studies have been published with PHS as a storage solution.
A comparative review of HRESs integrated with PHS storage systems based on techno-economic and environmental analysis was presented in. In, a standalone hybrid wind turbine (WT)/photovoltaic (PV)/biomass/PHS system was designed for the satisfaction of load demand, focusing on the minimization of the cost of energy. In, a PV/WT/PHS energy system was optimized for the techno-economic viability of the project and the supply of electricity at a significantly low cost.
The optimization of an HRES consisting of PVs, WTs and a PHS was presented in. As long as the installation of a PHS is permitted by the topography and wind speeds and solar radiation are high, the results show a promising solution for the electrification of a city in Libya, with a minimum value of LCOE of 0.130 EUR/kWh. In recent years, increasing attention has been given to the investigation of hydrogen as a storage option in HRESs.
Hydrogen can be produced locally, increasing the independence of the energy supply. In contrast to pumped storage systems, much less space is needed for the installation of the hydrogen production unit, and no specific topographic parameters are necessary. Hydrogen is considered a zero-emission fuel; however, when its production is powered by conventional fuels a large amount of CO2 is generated, which means hydrogen is not an environmentally friendly solution. The exploitation of RES for water electrolysis leads to the decarbonization of hydrogen, producing green hydrogen. Surplus energy from RESs can be utilized for the production and storage of green hydrogen for use when RES production is less than the load demand.
The operation of a PV/hydrogen system was examined in by analyzing the demand over 10 years and considering the degradation of the components in the total performance of the system. In a wind energy assessment in Afghanistan was investigated in all capital cities, considering three scenarios and five degradation rates, and a techno-economic analysis was conducted for a WT/hydrogen system to the city with minimum LCOE.
The system was designed to meet the electric load of a residential community by focusing on the increase in RES penetration, the reduction in greenhouse gas emissions and the minimization of the cost of energy. The levelized cost of energy was estimated at 0.14EUR/kWh.
A Guest Editorial