Capacity fee

Poland runs a capacity market under the Capacity Market Act of December 8, 2017 (ustawa o rynku mocy). Generators, storage operators and demand response providers win contracts in auctions and are paid for keeping capacity available. The capacity fee (opłata mocowa) funds those payments. Distribution system operators collect it from the users connected to their networks and pass it to the transmission system operator (Article 69). The operators include the rates in their tariffs.

Until the end of 2027 there are two regimes (Article 89a). Households, and other users connected at up to 1 kV with a contracted capacity of up to 16 kW, pay a flat monthly amount that depends on annual consumption: from 4.29 to 24.05 PLN net per month in 2026. Everyone else, which covers nearly every factory, warehouse and office building, pays per kWh drawn from the grid in selected hours. The President of URE, the energy regulator, publishes the rate and the hours every year; an amendment of September 12, 2025 moved the deadline from September 30 to October 31. For 2026 the rate is 0.2194 PLN/kWh net, and the selected hours are the fifteen hours from 7:00 to 22:00 on working days (Monday to Friday, excluding public holidays), the same in all four quarters.

The fee is then scaled by the load profile. Article 70a compares, for each metering point and each day, the average hourly consumption in the peak hours with the average hourly consumption in the other hours of the same working day: difference = (peak-hour average / off-peak average - 1) x 100%. The difference puts the day into one of four groups, and each group has a coefficient A. The fee for the day is A times the energy drawn in peak hours times the rate. A consumer with a flat profile pays 17% of the full rate; one whose peak-hour average is at least 15% above the off-peak average pays all of it. The qualification period was a calendar month in 2021 and 2022 and a ten-day period in 2023 and 2024 (Article 89e). Since 2025 it has been a single day of 24 hours (Article 70a(3)). Groups are assigned per metering point, and a consumer whose points are connected through its own network can ask the operator to merge them so that the group is assigned on their sum (Article 70b).

For a large consumer the capacity fee depends on when energy is used as well as how much. Any software that schedules production, controls a battery or checks invoices for such a site has to model it:

• The rule works on hourly volumes in MWh to three decimal places, per metering point and per day. Meter data at 15-minute resolution has to be summed to hours first.
• Peak hours are defined in local time on working days. The system needs a public holiday calendar and has to convert UTC timestamps correctly on the days the clocks change.
• The rate, the hours and the coefficients are configuration with a validity period. URE publishes new values every autumn for the next year, and the Act allows different rates for each quarter.
• The groups are steps. A few extra megawatt-hours in the peak hours can move a day from K1 to K2 and almost triple that day's fee. An optimizer has to put the fee into the cost function, because a fixed limit hides the trade-off.
• Off-peak hours count as well. Moving load into the night raises the off-peak average and lowers the difference, so a schedule change can improve the group without cutting peak consumption.
• Merged metering points are classified on their sum, so the model must know which points the operator has merged.
• For invoice control the system recomputes the group for every day from its own meter data and compares the result with the operator's bill.

Take a site that draws a flat 10 MW all day, which puts it in K1. If it adds 2 MW for eight hours around midday because the day-ahead price is low, its peak-hour average rises to about 11.07 MW, the difference reaches 10.7% and the day moves to K3. The fee for that day rises from 5,594.70 PLN to about 30,229 PLN. Running the same 16 MWh at night would keep the day in K1, so the midday run pays off only if midday energy is more than about 1,540 PLN/MWh cheaper than night energy. On days with deeply negative midday prices it can be.

The capacity fee is part of PowerShift, a module we built in 2026 for Enerace, an energy procurement advisory. PowerShift helps industrial plants with energy-intensive processes and some time flexibility, such as furnaces, mills, compressors, cold stores and pumps, plan when machines run so that the total cost is lowest. The model combines hourly prices and market signals, the tranches already contracted with their prices, the consumption profile that drives the capacity fee, and the plant's technical constraints and work schedule. It does not assume that crossing a K threshold must be avoided. It calculates whether, at a low enough or negative hourly price, a higher capacity fee still gives a lower total cost.

We added the capacity fee to the PowerShift backend and frontend between April and June 2026, and by October 2026 finished the optimal schedule that includes it. In the same period we corrected time zone handling in PowerShift.