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As energy system will increasingly become renewable, they will face new challenges that mainly arise due to the varying output by many renewable energy technologies. An issue that is especially prominent for countries with high shares of hydropower in their electricity generation is the varying yearly output of these technologies. This work aims to propose a techno-economically optimized energy system for such a country, using Portugal as example. For this purpose the current situation is analyzed and an energy demand model for 2050 created. The energy system is optimized for years with different outputs of hydropower to analyze the system's behavior using the simulation tool EnergyPLAN. As the tool does not possess inherent optimization capabilities it was coupled with the gray wolf optimization algorithm using Matlab. Subsequently, a system is proposed that is able to cover Portugal's expected energy demand under all circumstances. The future system will rely strongly on wind and solar power as they are expected to cover around 75% of Portugal's electricity demand. Furthermore, the analysis showed that Portugal needs to build up electrolyzer capacities of 4.2 GW and SynGas capacities of 2.4 GW as the SynGas will be used to balance supply in demand, especially in years with lower hydropower output. The system's cost will be between 22 and 35% cheaper than the created reference model. Furthermore, the primary energy demand is expected to decrease from 253 TWh to around 150 TWh while the electricity demand rises from 49 TWh to around 110 TWh. • We propose an optimized 100% renewable energy system for countries with high shares of hydropower. • The proposed system can cover Portugal's expected energy demand in 2050. • Wind and solar power are expected to cover around 75% of Portugal's electricity demand. • Portugal needs to build up electrolyzer capacities of 4.2 GW and SynGas capacities of 2.4 GW. • The system's cost will be between 22 and 35% cheaper than the created reference model. [ABSTRACT FROM AUTHOR]

The integration of intermittent renewable energy sources (RES) represents a great challenge for any energy system. In particular, islanded microgrids with a high penetration of renewables experience a strong need for technologies that allow to match demand and production at any moment. This work aims at proposing an optimised design for the energy system of Faial, an island in the Azores archipelago, featuring the highest possible renewable energy penetration that can be obtained respecting the technological and financial feasibility constraints. To this purpose, a model has been developed, using weather and electric demand measured data to combine and size optimally the components of a hybrid energy system. The model can be varied in its constraints to fit at best the multi-objective nature of the problem, where the conflicting objectives are the Net Present Value, its Renewable Energy Fraction and the Energy Index of Reliability. Once a set of possible optimal design has been determined, a system design featuring 5504 kW of geothermal installed power and 6208 kWh of BESS (Battery Energy Storage System) capacity, together with the already present thermal generators and 4250 kW of wind turbines, has been analysed more in detail. Monte Carlo simulations with synthetic time series have been performed to investigate the impact on the project of the variability in wind speed and in energy demand, highlighting the robustness of the selected design. • We propose an optimised design for the energy system of Faial, an island in the Azores archipelago. • The model features the highest possible renewable energy penetration respecting the technological and financial constraints. • Monte Carlo simulations were performed to investigate the impact of the variability in wind speed and energy demand. [ABSTRACT FROM AUTHOR]

The Polish coal-based power system faces the necessity of a pressing transition. Partially, the challenge may be addressed by floating photovoltaics. Since there is no analysis covering the implementation of this technology in Polish conditions, in this paper the design process of a 1 MWp floating photovoltaic system and its technical and economic assessment were performed. To find the best solution different floating assemblies were considered. Floating systems were compared with the reference ground mounted system and, based on simulations conducted in PVsyst, economic study with sensitivity analysis was carried out. The results revealed that even in case of the best performing floating system the extra yield cannot compensate the higher CAPEX. Currently, in Polish market conditions, this technology is not as profitable as the ground-mounted systems and higher product maturity stage need to be achieved for it to be considered as competitive. [ABSTRACT FROM AUTHOR]