Analysis of cooperation between cogeneration power plants and renewable energy sources to enhance the stability of the National Power System: Case study of Poland

In Poland rapid growth in renewable capacity presents new challenges for power system operators. In recent years, electricity price fluctuations and constraints on renewable energy generation have become increasingly common in the Polish electricity market. These constraints are mainly caused by short-term surpluses of weather-dependent renewable generation, most frequently occurring around midday. At the same time, Poland possesses one of the most developed district heating systems in the world, supplying heat to over 15 million customers. A substantial share of this heat is produced in cogeneration units that generate electricity and heat simultaneously. The installed electrical capacity of these units exceeds 7 GW. Given the rapid expansion of renewable energy and the advanced state of the heating sector, there is a strong case for enhancing cooperation between different sectors and technologies. Such integration can improve the operational security of the power system, enhance supply stability, and increase the flexibility of generation assets. In this context, the present study focuses on analyzing the operation of selected existing cogeneration units and their multi-level potential for integration with renewable sources such as wind turbines and photovoltaic farms. The goal is to maximize the stability of energy production during periods of demand within the National Power System. The study also seeks to determine the extent to which cogeneration units can cooperate with wind turbine and PV installations, and to identify metrics suitable for evaluating this cooperation under varying conditions of heat and electricity demand. The analyses cover hourly, daily, and monthly time scales. • CHP units significantly improve hourly, daily, and monthly power system balancing. • Strong negative correlation with PV shows high CHP potential for Duck Curve mitigation. • CHP plants provide rapid flexible response with large intra-hour generation variability. • Seasonal synergy with wind and heat demand enhances CHP value during low-RES periods.