Heat-hit coal plants force Poland’s PSE to activate capacity market again

Reserve falls below the security requirement

Polish transmission system operator Polskie Sieci Elektroenergetyczne, or PSE, activated the country’s capacity-market mechanism again on 6 August 2026 as high temperatures constrained several coal-fired power stations. Energia.rp.pl reported that the legally required generation reserve would be unavailable between 17:00 and 22:00. PSE expected the reserve to fall to between 932 MW and 597 MW during the most constrained period from 17:00 to 19:00.

The low point was below 600 MW, compared with nearly 660 MW during the previous activation on 4 August. PSE uses 1,000 MW, approximately the capacity of one large coal-fired power plant, as an operational reference for remedial action. The capacity margin available above consumer demand was also substantially below the 9% required for secure operation of the power system.

The activation did not indicate an imminent blackout. It required generators covered by capacity contracts to make their committed capacity available or inject electricity into the grid, depending on the type of unit. Contracted consumers were required to reduce demand. PSE said the mechanism would not disrupt household customers, although consumers finance it through the capacity charge included in electricity bills.

Cooling limits reduce output at major coal sites

The immediate pressure came primarily from coal units operated by Enea at Kozienice and Połaniec, with additional capacity losses at PGE’s Turów plant. Energia.rp.pl reported that 10 of Kozienice’s 11 units were recording emergency capacity losses. The B11 unit, Poland’s largest coal unit with capacity above 1,000 MW, was already undergoing a previously scheduled overhaul from the beginning of July until September.

At Połaniec, seven of nine units were affected by high capacity losses, reaching more than 200 MW. Problems were also reported at Turów, while one unit at Orlen’s EC Żerań was not operating. The growing number of constrained units and the extension of the capacity-market activation to four hours showed that the system’s position had deteriorated since 4 August, when the mechanism was called for two hours.

High cooling-water temperatures were identified as the likely reason for the reductions. Water used by the plants is returned to rivers, and its permitted discharge temperature is 35 degrees Celsius. Operators must therefore curb generation when continued operation could breach that limit. Enea Wytwarzanie said it was observing periodic fluctuations in water flows and reduced water levels during high temperatures and prolonged periods without rainfall. At Kozienice, access to water from the Vistula River directly affects the stability of plant processes and the security of Poland’s power system.

Fifth activation tests the backup mechanism

This was the third capacity-market activation in 2026, after calls on 30 June and 4 August, and the fifth since the mechanism began operating. It was also the second activation in the same week. Poland adopted its Capacity Market Act at the end of 2017 to pay generators and participating consumers for remaining available when system reserves become insufficient.

PSE can normally protect the reserve by changing maintenance schedules, ordering higher generation, running plants above standard output or using pumped-storage facilities. Emergency imports were not available in this case because neighbouring systems faced similar conditions, according to Energia.rp.pl. That left the capacity market as the principal instrument for restoring the required buffer while heat continued to limit thermal generation.