The power fee: when your peak costs money
A power fee is based on how much electricity you use at the same time. It rewards spreading loads out.
Checked by Radif Partners · Editorial policy · Method and sources
A power fee is the part of the network fee set by a site’s highest power, meaning simultaneous use, not just the energy consumed. Of the calculator’s 72 networks, 3 have household products with a power fee (Helen Sähköverkko, Lahti Energia, Kuopion Sähköverkko). Helen charges 1.97 euros per kilowatt per month, based on the month’s third-highest hourly average power, with 80% of night-time power counted. Kuopio charges 1.32 euros per kilowatt per month on the billing month’s highest hour. At a 5 kW peak the power fee is about €118 a year with Helen and €79 in Kuopio. Lahti Energia’s power products use the highest hour of the previous 12 months and are the only choice there for a detached house. You lower the peak by staggering large appliances across hours: car charging, the sauna stove, the water heater and direct electric heating are the usual culprits.
What does the power fee cost?
Power fee per year
€142
| Per month | €11.82 |
| Rate | €1.97/kW/month |
| Each kW less saves per year | €23.64 |
Power fees in the calculator’s networks
| Network and product | Power fee | Basis | 5 kW per year | 10 kW per year |
|---|---|---|---|---|
| Helen Sähköverkko, Aikasiirto | 1.97 €/kW/month | third-highest hourly average power of the month; night-time power counted at 80% | €118 | €236 |
| Lahti Energia, Yleissiirto teho | 1.00 €/kW/month | highest hourly average power measured over the previous 12 months | €60 | €120 |
| Lahti Energia, Yösiirto teho | 1.00 €/kW/month | highest hourly average power measured over the previous 12 months | €60 | €120 |
| Kuopion Sähköverkko, Aikasiirto | 1.32 €/kW/month | highest hourly average power of the billing month | €79 | €158 |
The basis varies: some operators use the month’s highest or third-highest hour, Lahti Energia the highest hour of the previous 12 months. A fee based on the annual peak punishes a single large hour for longer, so managing the peak pays especially in such a network.
What drives the peak up
- Sauna stove: a 6–9 kW stove lifts the hourly average almost by its full power while heating. See sauna cost.
- Car charging: a three-phase 16 A charger charges at 11 kW. See EV charging.
- Water heater: typically a few kilowatts, often at night.
- Direct electric heating: in frost all radiators may be on at once.
When these land in the same hour the peak can exceed 20 kW. Staggering them across hours can keep it under half that.
How to lower the peak
- Charge the car at lower power for longer, or use the charger’s load management, which cuts charging while other appliances run.
- Do not heat the sauna while the car charges or the water heater warms up.
- Move large loads to the night if your product counts only part of night-time power, as Helen’s does.
- Follow your hourly use in the operator’s portal to see which hours set the fee.
Motiva’s demand-flexibility guide explains how home automation can steer loads. Note the tension with spot pricing: concentrating use in the cheapest quarter can raise the peak. The best approach spreads the load over several cheap hours.
Why power fees are used
A grid is sized for the largest simultaneous demand, not the year’s energy. A power fee allocates network costs where power is needed and encourages smoothing use. Motiva’s transfer fee page explains the structure of network fees. Compare networks in the transfer fee comparison, where you can enter your own peak power.
Example: an ordinary winter evening
Picture an electrically heated house on a winter evening. Radiators run, the car goes on charge after work, and the sauna is heated later. If these land in the same hour, the hourly average can be several times a normal hour. With a third-highest-hour basis one such evening may not set the fee, but repeated evenings lift the peak for good. Charging overnight, heating the sauna before plugging in the car and timing the water heater for the early hours shrink the evening peak, and every kilowatt cut saves twelve times the monthly rate a year.
Automatic load management
Many car chargers measure the house’s total use and throttle charging when other appliances draw a lot; home automation can do the same for the water heater and heating. That keeps the peak down without anyone remembering to stagger appliances, and it also protects the main fuse from tripping.
Check your contract before switching to a power-fee product, and use the hourly data in your operator’s portal to estimate your typical monthly peak.