A techno-economic-environmental assessment of a hybrid-renewable pumped hydropower energy storage system: A case study of Saudi Arabia

The depletion of valuable resources like oil and natural gas and the growth of greenhouse gas emissions have led governments worldwide (e.g. Saudi Arabia) to prioritise renewable energy sources. However, designing and implementing such sources are subject to sensitive technical, economical, and environmental factors. The current study aims to accurately design each component of a hybrid renewable energy system consisting of photovoltaic/wind turbines/pumped hydropower energy storage relying on the development of a multi-objective optimisation model. To increase the robustness of the model outcomes, objectives include incorporating a head loss factor into the model, considering a capacity factor as the main metric for energy storage design, and conducting a techno-economic environmental assessment considering greenhouse emission credit. Three algorithms (non-dominated sorting, reference direction-based, and two-archive evolutionary) are developed, and a comparative analysis with Saudia Arabia as a case study is carried out. The results show that considering a combination of solar and wind energy in a hybrid renewable energy system could cover up to 93 % of total demand, with a maximum pumped hydro capacity factor of 27 %. This combination is much better than using solar or wind alone (i.e. 62 % and 70 %, respectively) at a capacity factor of pumped hydro of 18 %. The levelised cost of energy for the proposed system ranges between 0.07 and 0.22 $/kWh, largely influenced by proposed Saudia Arabia government subsidies. Regarding environmental assessment, the total amount of greenhouse gas emissions generated annually from all proposed systems is between 2.4 and 11 million tonnes.