Spot Electricity Calculator

How the price of spot electricity is formed

In a spot-price contract the energy price follows the spot price of the Nord Pool power exchange, where a separate price is set for every hour of the day based on supply and demand. Finland forms its own bidding zone, so the prices you pay are the Finnish area prices. On top of each hour's market price you pay the seller's margin, typically around 0.2–0.6 cents per kilowatt-hour. The hourly prices for the next day are published already in the previous afternoon, so expensive and cheap hours are known in advance.

Transmission and electricity tax are always paid separately to your local grid company — they are the same regardless of whether you have a spot-price or a fixed-price contract, which is why they are not included in this comparison. Any fixed monthly fees are also left out, as they are usually of a similar size in both contract types. Spot prices vary strongly: cold and calm winter spells push prices up, while on windy nights the price can fall close to zero. If you want to estimate the consumption and cost of individual appliances, also try our electricity cost calculator.

Spot or fixed price — which one suits whom

Spot-price electricity suits you if you can tolerate variation in your monthly bill and can at least partly shift your consumption to cheap hours. Over the long term spot-priced electricity has often been cheaper than fixed contracts, because a fixed price includes the seller's risk premium. On the flip side, a single cold and low-wind winter month can temporarily push your bill well above normal — you need to be able to carry that risk.

A fixed contract suits you if you want a predictable electricity bill and do not want to follow hourly prices. Especially in a house with electric heating, where consumption is concentrated in the most expensive winter hours and heating cannot easily be shifted, a fixed price reduces the risk significantly.

The break-even price shown by the calculator tells you at what annual average spot price the two options cost the same: it is the fixed price minus the margin. If you believe the realised average will stay below it, spot-price electricity is the cheaper choice on paper — and vice versa. Remember to make the estimate based on your own consumption profile: heating electricity concentrated in winter raises your realised average price.

How to reduce your spot electricity bill

The biggest advantage of spot-price electricity is that you can influence your own bill. The spot price is typically at its lowest at night and in the early morning hours and on windy days, and at its highest on weekday mornings and early evenings when demand is high. Schedule large loads — laundry, the dishwasher, electric car charging, water heater and sauna heating — to cheap hours with a timer or smart control.

The hourly prices for the next day are published in the previous afternoon, so the cheapest hours can be checked in advance from free apps and services. In a house with electric heating you can store heat in the structures by heating a little more during cheap hours and letting the temperature drop during expensive ones. Note that timing does not affect the transmission fee or the electricity tax, unless your grid company offers separate night-time transmission pricing. Even modest load shifting can clearly lower your realised average price — try different average spot prices in the calculator and see how the result changes.

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