OPERATION OF A POWER UNIT AS A PEAK UNIT AND ITS IMPACT ON THE ECONOMY AND RELIABILITY OF THE POWER SYSTEM

For several years in Europe, there has been a dynamic change in the structure of energy sources supplying domestic systems. The driving force behind these changes is, among others: efficiency of fuel energy use, costs of electricity generation, safety and reliability of power plant operation, depleting fuel resources and, what has been the most important recently – ecology. The ecological aspect has its supporters and opponents. EU legislation has forced pro-ecological changes in the structure of energy sources. Among renewable sources, the leader is wind energy, the operation of which depends on changing weather conditions. Giving priority to energy from RES forces the operation of some conventional units as a safeguard for wind power plants and causes difficulties in balancing the system’s demand. In August 2015, for the first time in 30 years, the “20th power rationing level” was implemented, which in short means limitations in energy consumption for industrial customers. The steps taken were to prevent the system blackout. The main reason for this state of affairs was the long-term heat, which limited the possibility of cooling the steam-water circulation of power plants. The low water level in the reservoirs limited the production capacity of water power, and the high-pressure windless weather immobilised almost 4.5 GW of power installed in wind power plants. The summer period is also a natural time to carry out scheduled repairs of power units, which has further intensified the power deficit. All these reasons coincided with time, which resulted in the inability to cover the demand for electricity. Figure 1 shows the course of changes in the maximum power demand in the national system in the peAndrzej RUSIN, Adam WOJACZEK