Energy transition forcing a change in the structure of the electricity generation system is a particularly difficult task in countries such as Poland, where the dominant source of energy is fossil fuels. Due to the nature of renewable sources (stochastic and seasonally variable), it is necessary to study their impact on the power system. Much research was conducted on this subject. They consider modelling power systems in terms of dealing with an increasing amount of renewable energy sources, stabilization of electricity generation or environmental aspects. This article examines one of the key sources of future power systems—offshore wind turbines (OWT). The influence of offshore wind sources on the power system in the fields of stability of generation, methods of regulatory strategies, and economics were examined. One of the aspects that are less considered is the correlation of energy production in OWT with energy demand and with generation in other renewable energy sources, especially in the region of the southern Baltic Sea and the distribution of energy demand in countries such as Poland. The key aspect of the research is to fill this gap. The obtained results indicate that the average monthly power generation in OWT is strongly positively correlated with the demand, and the hourly average is positively correlated moderately. Correlation between generation in OWT and photovoltaic sources is very high negative, and between onshore and offshore wind turbines is highly positive. The study indicates that the OWT has a significant potential for the development and replacement of conventional sources, due to the very high capacity and a positive correlation with demand. Moreover, future offshore wind farms can cooperate with photovoltaic sources as these sources complement each other. On the other hand, a significant saturation of the system with offshore and onshore wind sources may pose a threat to the power system due to their positive correlation.

Today, the increasing amount of waste is a growing ecological and financial problem. Another issue is the need to limit the share of controllable sources powered by fossil fuels. A hybrid generation system (HGS) is proposed to solve both problems. The system consists of renewable energy sources (RES) and a waste gasification system. Contrary to many papers, it is proposed to include syngas storage and use gas turbines as balancing sources. The HGS was modeled, and electricity generation, capacity factors, and efficiencies were calculated. The economic (LCOE and PP) and environmental parameters (CO₂ emission and reduction) were analyzed and calculated for different RES capacities. The results show that the proposed HGS covered 45.7–80% of municipal demand. The HGS was characterized by high CO₂ emissions, due to the low efficiency of gasification-gas turbine installation and the need to compress syngas. However, the HGS can be environmentally beneficial due to the reduction in waste disposal in landfills. The LCOE was EUR 174–191 with a minimum at the RES capacity of 14 MW. Any change in waste disposal costs and emission allowances would cause significant changes in the LCOE. It was found that it can be beneficial to use a gasification system as a balancing source in a HGS.

This paper presents factors affecting the effectiveness of photovoltaic (PV) plants and issues occurring in the distribution system network due to the high penetration of conventionally designed PV plants. Factors analyzed in this paper are shading, distance between panels, location of PV plants, European grid code requirements, and network constraints. Their impacts on the effectiveness of the PV power plant are presented one by one. Furthermore, the 1-year power profile of a real PV plant is rescaled to different orientations, and the energy effectiveness of different variants is compared. Finally, the economic aspects are considered by multiplying the energy produced by the energy prices. At the end, final conclusions are given and further research is outlined.