Solar power

Solar power's share of Finnish electricity production is still small (usually under 5 %) but growing. Finland's latitude poses a seasonal challenge: solar panels operate near full rated output at midday in June, but at only 5–10 % of rated output at midday in December.

Household solar panels affect the bill in two ways: 1) during self-consumption, the panels' electricity does not come from the grid, so you save both energy and transfer costs, 2) surplus production can be sold to the utility, typically at the spot price or a fixed agreed rate.

In the Finnish system, solar production correlates negatively with the spot price in spring and summer: on sunny days the spot price drops around midday because a lot of cheap solar electricity flows into the grid.

Solar power seasonality in Finland

In June a typical Finnish solar panel system (5 kWp) produces about 650–750 kWh/month. In December production is only 20–40 kWh/month — more than a 20× difference. However the annual yield in Finland (900 kWh/kWp) is surprisingly close to Central European values, because long summer days compensate for short winter days.

Ideal Finnish installation: 30–45° tilt, south-facing (deviation ±30° is still good). Panel costs dropped 60 % during 2015–2024 — a 5 kWp system with installation now costs 7,000–11,000 €.

Economic impact of solar panels

Self-consumed solar electricity saves both the energy fee (about 7–10 c/kWh) and the transfer fee (3–5 c/kWh). The saving is thus 10–15 c/kWh — clearly more than the sell-to-grid price (typically 4–6 c/kWh on spot or an agreed fixed price).

Payback time for a 5 kWp system in Finland is currently about 8–12 years. If you use an EV or hot-water boiler during daytime, payback shortens because self-consumption share rises.

Solar power in the spot price

In midsummer sunny Saturdays are often the cheapest electricity days of the year — the spot price can drop below 0 c/kWh at 10:00–14:00 (negative price). A spot-contract customer benefits: daytime consumption is then free or you even get money back.

If you have an EV, consider charging on sunny Saturday–Sunday afternoons in summer: the cheapest hours of the year on a round-the-clock basis fall precisely there.