Influence of the wind energy sector on thermal power plants in the Polish energy system

Wind power is one of the most popular renewable energy sources, characterized by a rapid growth of installed power in the energy mix of many countries. This trend is also observed in Poland, where the share of wind energy in the electricity production has grown over 25 times in the last decade, now reaching almost 10%. The remaining part of the power system, consisting mostly of coal-fired power plants, does not remain unaffected. Since renewable energy has priority in access to the grid, the dispatchable coal-fired power plants need to adjust their load, compensating for the intermittent operation of wind turbines. This causes additional consumption of primary energy due to more frequent shut-downs/start-ups of the power units and due to efficiency penalty when operating below nominal parameters. In this paper, actual data on the operation of Polish power plants in several years are analyzed. The analysis, together with simulations of performance of the power system without the presence of wind energy, aims to answer the question how strong is the influence of wind power plants on the utility coal-fired ones. A conclusion is that current share of wind energy at the level of 10% is enough to be perceptible by the coal power plants, but too small to significantly decrease the overall efficiency of the power system.