How we calculate
432 scenarios per city, calculated 2026-11-10. The examples are for Stockholm.
Engine
The same as our calculator. The sun's position is calculated every 15 minutes; power, battery and car hour by hour, one full year. Each city has 432 scenarios: six roof directions, three sizes, with and without a battery, with and without an electric car, three levels of power use and two day patterns.
House
Made up, in the city centre: 27° roof, no shade, 420 W panels, a 10 kWh battery. The car drives 30 km a day.
Weather and power price
Weather: PVGIS for the place. Power price in Stockholm: SE3 spot 2025-11-10 to 2026-11-10 + markup 0,05 kr + Ellevio 0,21 kr + energy tax 0,36 kr (Swedish Tax Agency 2026) + 25% VAT = 1,76 kr/kWh. The data
Price
Numsolar's example price list for installers (version 9), incl. VAT, after the green tech deduction for one owner. The same price in every city. No charger. Your installer's price will differ.
Payback and net
Payback = price ÷ first-year savings. Net over 25 years = 25 years of no-battery savings + 10 years of battery savings − price. The battery counts only during its warranty.
Not counted
Panel ageing (about 0.4%/yr), an inverter swap after 12–15 years, a changed power price, peak charges. They cut the net by about 15%; the ranking holds.
The power price per city
What a bought kWh costs in each city, with the source of the grid fee.
| City | Zone | Spot average | Grid fee | Energy tax | Per bought kWh |
|---|---|---|---|---|---|
| Malmö | SE4 | 1,05 kr | 0,28 kr | 0,36 kr | 2,17 kr |
| Växjö | SE4 | 1,05 kr | 0,28 kr | 0,36 kr | 2,17 kr |
| Västerås | SE3 | 0,79 kr | 0,43 kr | 0,36 kr | 2,04 kr |
| Lund | SE4 | 1,05 kr | 0,16 kr | 0,36 kr | 2,02 kr |
| Helsingborg | SE4 | 1,05 kr | 0,14 kr | 0,36 kr | 1,99 kr |
| Uppsala | SE3 | 0,79 kr | 0,36 kr | 0,36 kr | 1,95 kr |
| Halmstad | SE4 | 1,05 kr | 0,08 kr | 0,36 kr | 1,92 kr |
| Örebro | SE3 | 0,79 kr | 0,28 kr | 0,36 kr | 1,85 kr |
| Norrköping | SE3 | 0,79 kr | 0,28 kr | 0,36 kr | 1,85 kr |
| Eskilstuna | SE3 | 0,79 kr | 0,24 kr | 0,36 kr | 1,80 kr |
| Jönköping | SE3 | 0,79 kr | 0,23 kr | 0,36 kr | 1,80 kr |
| Stockholm | SE3 | 0,79 kr | 0,21 kr | 0,36 kr | 1,76 kr |
| Göteborg | SE3 | 0,79 kr | 0,18 kr | 0,36 kr | 1,73 kr |
| Borås | SE3 | 0,79 kr | 0,13 kr | 0,36 kr | 1,66 kr |
| Gävle | SE3 | 0,79 kr | 0,12 kr | 0,36 kr | 1,65 kr |
| Linköping | SE3 | 0,79 kr | 0,12 kr | 0,36 kr | 1,65 kr |
| Karlstad | SE3 | 0,79 kr | 0,08 kr | 0,36 kr | 1,61 kr |
| Sundsvall | SE2 | 0,46 kr | 0,21 kr | 0,36 kr | 1,36 kr |
| Umeå | SE2 | 0,46 kr | 0,18 kr | 0,26 kr | 1,20 kr |
| Luleå | SE1 | 0,45 kr | 0,00 kr | 0,26 kr | 0,95 kr |
- Stockholm: Ellevio, Säkringsabonnemang 16–63 A, priser from 1 June 2026
- Göteborg: Göteborg Energi Elnät, 2026 års elnätspriser för villa (read 2026-11-08)
- Uppsala: Vattenfall Eldistribution, Säkringsabonnemang 2026 Privat, from 1 January 2026
- Linköping: Tekniska verken, Prislista standard, from 1 January 2026
- Västerås: Mälarenergi Elnät, Priser privat- och företagskunder, from 1 July 2026 (read 2026-11-09)
- Helsingborg: Öresundskraft Elnät, Elnätsavgifter villa, from 1 January 2026 (read 2026-11-09)
- Jönköping: Jönköping Energi Nät, Priser säkringstariff, from 1 September 2026 (read 2026-11-09)
- Umeå: Umeå Energi Elnät, Elnätspriser 2026, from 1 January 2026 (read 2026-11-09)
- Lund: Kraftringen Nät, Komplett prislista för elnätsavgifter, from 1 July 2026 (read 2026-11-09)
- Borås: Nätkraft Borås, Säkringsabonnemang utan effektavgift, from 1 January 2026 (read 2026-11-09)
- Eskilstuna: Eskilstuna Energi och Miljö Elnät, Elnätsavgift 2026, from 1 January 2026 (read 2026-11-09)
- Halmstad: HEM Nät, Uttagsabonnemang, from 1 January 2026 (read 2026-11-09)
- Gävle: Gävle Energi, Elnätspriser from 1 January 2026 (read 2026-11-09)
- Karlstad: Karlstads Elnät, Elnätsavgifter 2026, from 1 January 2026 (read 2026-11-09)
- Sundsvall: Sundsvall Elnät, 2026 Säkringsabonnemang Privat, valid until 31 December 2026 (read 2026-11-09)
- Luleå: Luleå Energi Elnät, Prislista Elnät, fuse 20 A (N020), from 1 January 2026 (read 2026-11-09). No variable grid fee, only a fixed fee of 668 kr/month.
- Växjö: a typical grid fee, because Växjö Energi’s fee follows the spot price and the calculation cannot model that.
- Malmö, Örebro, Norrköping: a typical grid fee, because we have not been able to read E.ON’s price list.
Data
Every scenario as JSON, free to use with attribution (CC BY 4.0).
All cities, one row per city (JSON) · Spot price 2025-11-10 to 2026-11-10. Data from 2026-11-10.
The data
The data behind every number on the page, per month or year. Click a dotted number to open it.
What a bought kWh costs
Every kWh of solar you use yourself is one you do not buy at this price.
| Part | kr/kWh |
|---|---|
| Spot price, average | 0.79 |
| Retailer markup | 0.05 |
| Transfer fee, Ellevio | 0.21 |
| Energy tax | 0.36 |
| VAT 25% | 0.35 |
| Total | 1.76 |
Average over the year; the fixed monthly fee is not per kWh.
Source: priv/data/city_solar/<city>.json · model.import_price, city_facts.dso · Skatteverket (energiskatt)
The SE3 spot price per month and hour
The spot price changes over the year and the day. Solar sold at midday often gets less than the average.
| Hour | Average kr/kWh |
|---|---|
| 00:00 | 0.67 |
| 01:00 | 0.63 |
| 02:00 | 0.61 |
| 03:00 | 0.60 |
| 04:00 | 0.61 |
| 05:00 | 0.67 |
| 06:00 | 0.82 |
| 07:00 | 0.98 |
| 08:00 | 1.00 |
| 09:00 | 0.88 |
| 10:00 | 0.76 |
| 11:00 | 0.68 |
| 12:00 | 0.63 |
| 13:00 | 0.60 |
| 14:00 | 0.62 |
| 15:00 | 0.70 |
| 16:00 | 0.83 |
| 17:00 | 1.00 |
| 18:00 | 1.10 |
| 19:00 | 1.11 |
| 20:00 | 1.04 |
| 21:00 | 0.94 |
| 22:00 | 0.82 |
| 23:00 | 0.71 |
| Year | 0.79 |
Excl. VAT, markup and grid fee. 2025-11-10 to 2026-11-10.
Source: priv/data/city_solar/<city>.json · city_facts.spot_profile, city_facts.zones · Nord Pool via electricity_spot_prices
The price line by line
The price incl. VAT minus the green tech deduction is what you pay. The battery reaches the 50 000 kr cap for one owner.
| System | Price incl. VAT | Green tech | To pay |
|---|---|---|---|
| 10 panels (4.2 kW) | 102 941 kr | −14 978 kr | 87 963 kr |
| 20 panels (8.4 kW) | 154 412 kr | −22 467 kr | 131 945 kr |
| 30 panels (12.6 kW) | 205 883 kr | −29 956 kr | 175 927 kr |
| 10 panels (4.2 kW) + 10 kWh battery | 185 294 kr | −50 000 kr | 135 294 kr |
| 20 panels (8.4 kW) + 10 kWh battery | 236 765 kr | −50 000 kr | 186 765 kr |
| 30 panels (12.6 kW) + 10 kWh battery | 288 235 kr | −50 000 kr | 238 235 kr |
Numsolar's example price list for installers, 2026-11-10; green tech 15%/50% of 97% of the price, at most 50 000 kr per person and year.
Source: priv/data/city_solar/<city>.json · scenarios[*].price_kr, gron_teknik_kr; model.price_list · Skatteverket, grön teknik