The Polish capacity fee: how it works and how to cut it
What the Polish capacity fee is, who pays it and how the daily K1-K4 formula works. Why it is not only how much grid energy you draw that counts but also when - and why dropping from K4 to K1 cuts this bill line by 83%.
The capacity fee is a line on the distribution bill that funds the Polish capacity market - power plants being paid to stay ready when the grid is under stress. Households pay a flat monthly rate, but hourly-settled businesses pay for every kilowatt-hour drawn during peak hours, multiplied by a factor that depends on the shape of their daily load profile. The difference between the best and the worst band is as much as 83% of this bill line.
We have also put the rates, the peak hours and the category thresholds in a guide, Capacity fee: what it is and who pays, with a calculator of the K1-K4 category for one day.
What is the capacity fee?
The Polish power system needs a capacity reserve: plants that are ready to run exactly when demand peaks. The 2017 Capacity Market Act created a mechanism in which generators are paid for that readiness - and its cost lands on consumer bills as the capacity fee (opłata mocowa), collected by distribution system operators.
The key idea: since we pay for the system to be ready during peak hours, the fee should depend on how much energy you draw exactly then. That is why, for hourly-settled businesses, the capacity fee is not a flat charge - it is a function of your load profile.
Who pays, and how much?
Everyone pays the capacity fee, but under two very different models:
1. Households and small consumers (contracted power ≤ 16 kW) - flat rate
A fixed monthly amount that depends only on annual consumption. The 2026 rates:
| Annual consumption | Fee (zł/month, net) |
|---|---|
| below 500 kWh/yr | 4,29 zł |
| 500 – 1200 kWh/yr | 10,31 zł |
| 1200 – 2800 kWh/yr | 17,18 zł |
| above 2800 kWh/yr | 24,05 zł |
You cannot influence the flat rate other than by using less energy overall - so the rest of this article is about the second group.
2. Hourly-settled businesses (contracted power > 16 kW) - a rate on peak-hour consumption
Since 2021-2022 for high- and medium-voltage consumers, and since 1 January 2025 also for low-voltage businesses with contracted power above 16 kW, the fee is charged hourly: on every kilowatt-hour drawn from the grid during peak hours - working days between 7:00 and 22:00 (statutory holidays excluded).
The base rate keeps climbing:
Rates are published yearly by the President of URE (the energy regulator). The 2026 rate is up ~55% year on year.
The formula: K1-K4 bands and the Δs coefficient
Here is where it gets interesting. The law rewards consumers with a flat load profile: if you draw energy evenly around the clock, you pay only a fraction of the rate. If your consumption is concentrated in peak hours - you pay the full rate.
For every single day a coefficient Δs is computed - by how much your average hourly peak-time draw exceeds your average hourly off-peak draw:
The Δs value assigns the day to one of four bands:
| Band | Δs | Rate multiplier |
|---|---|---|
| K1 | < 5% | ×0.17 |
| K2 | 5% – 10% | ×0.50 |
| K3 | 10% – 15% | ×0.83 |
| K4 | ≥ 15% | ×1.00 |
The thresholds are hard: a day at Δs = 14.9% pays ×0.83, while a day at Δs = 15.0% pays the full rate on ALL of that day’s peak energy.
Since 2025 the K band is determined separately for every single day. There is no one "company category" - each working day is classified and billed on its own. One careless day does not ruin the month, but every day is a fresh game you have to win again.
What does it cost in practice?
Take a manufacturing site with ~200 kW of contracted power that draws 1,200 kWh from the grid during peak hours each day. At the 2026 rate (0.2194 zł/kWh):
Per month (~21 working days) that is ~5529 zł vs ~940 zł. With the same peak-hour energy, the difference of about 4589 zł a month comes purely from the K band, that is, from how your grid draw splits between peak hours and the rest of the day.
How to save - and why it is hard
Three levers act on the capacity fee:
- Less grid energy in peak hours - every kilowatt-hour covered from PV or a battery instead of the grid saves rate × multiplier, whatever your band.
- Shifting consumption off-peak - energy drawn at night or on weekends is not charged at all.
- Dropping to a lower K band - the most powerful one: crossing a threshold downwards reprices ALL of the day’s peak energy. K4 to K1 means -83%.
A battery takes over part of the peak-hour draw and refills outside it. The site’s total consumption does not change - what changes is WHEN energy flows from the grid. Δs falls from ~139% (K4) to below 5% (K1).
Sounds simple? In practice this is one of the trickiest optimization problems on an energy bill:
- The formula has two sides. Δs compares the peak with the "quiet" part of the day. The "just use less" intuition can backfire: cutting night-time draw can push you UP a band, because the denominator shrinks. And vice versa - sensibly charging a battery overnight can improve the whole day’s classification.
- Hard thresholds, daily classification. The result is decided by the full day, which you must plan in advance - from consumption and PV forecasts that are never perfect. A few percent of error at a band boundary changes the rate for the entire day.
- The fee competes with energy prices. On dynamic tariffs the cheapest hours often fall inside the capacity-fee peak window. The battery then has two conflicting jobs: buy cheap and keep the profile flat. The optimal decision changes hour to hour and day to day.
- The calendar plays too. Weekends and holidays are entirely off-peak - a plan for Friday and one for Saturday are two different problems.
Steering this by hand - 96 quarter-hours a day, two conflicting objectives, uncertain forecasts and hard thresholds - is practically impossible. This is a job for algorithms.
EnergyPal’s algorithms schedule your battery and PV for every quarter-hour of the coming days, combining energy prices, consumption and generation forecasts and the full capacity-fee arithmetic - daily K classification and its thresholds included. The plan refreshes automatically every few hours as new forecasts arrive.
The plan counts the capacity fee as a cost alongside energy prices and does not force a lower band at any price. If on a given day it is cheaper to charge the battery in the cheapest hours, even when they fall in the peak window, and stay in a higher band, that is what the plan does. The lever available every day, with any battery, is less grid energy in peak hours. Whether a site drops to a lower band depends on the battery size relative to its peak-hour draw, so we check it on the site’s own data before we quote any saving from a lower band. Capacity-fee optimization is a per-connection setting for business connections above 16 kW with hourly settlement on a dynamic tariff.
Summary
- The capacity fee funds the system’s capacity reserve; for businesses > 16 kW it is charged hourly on working-day 7:00-22:00 consumption.
- The K1-K4 multiplier (×0.17 to ×1.00) depends on the daily Δs coefficient, which compares your average hourly grid draw in and outside peak hours. So it is not only how much energy you draw that counts, but also when.
- The rate keeps rising (+55% YoY in 2026), so the value of optimizing rises with it.
- A battery with good planning acts on this bill line in two ways: less grid energy in peak hours, possible with any battery, and a lower K band, as far as K1, where the battery is large enough. The plan uses them when they lower the total bill.
