Under the Smart Export Guarantee you receive a few pence to around 15p per exported kWh, while you pay 25p or more to import. Many UK households also use time-of-use tariffs, which this version does not model yet. Start with UK values and enter your own rates.
Starting values only. Your bill is the source of truth: enter your own import and export price in the simulator above.
| Typical import price | £ 0.24 – 0.30 per kWh |
|---|---|
| Export | Smart Export Guarantee, typically £ 0.04 – 0.15 per kWh depending on supplier |
| Solar yield | about 850 – 950 kWh per kWp per year |
| Battery prices | about £ 400 – 700 per usable kWh installed |
The export rate on your actual tariff. Rates differ a lot between suppliers; a high SEG rate makes a battery less valuable.
Not yet. Time-of-use tariffs can make a battery worth more, by charging cheaply at night. That is on the roadmap.
Enter the all-in price you pay per kWh, including VAT. The result is then in the same terms as your bill.
Other countries: NetherlandsGermanyBelgiumIrelandFranceSpainItalyAustriaSwitzerlandAustraliaUnited StatesSouth Africa all countries
Change anything. Results update instantly. Pick a country for typical starting values, then type your own tariff from your bill.
Same roof and prices, only the battery changes. Bigger is not always better: once the battery covers your evenings, extra kWh sit idle.
| Battery | Battery saving / yr | Self-sufficient | Cycles / yr | Payback |
|---|
Every 15 minutes the simulator decides where each kilowatt-hour goes. Solar covers your use first, the surplus charges the battery, the battery covers your evening, the rest goes to or comes from the grid.
Your yearly kWh is spread over 365 days using a daily pattern for your profile: evening peaks for a home, daytime use for a business, more in winter than in summer.
Your panels produce a bell curve each day, long in summer and short in winter, scaled to the yield per kWp for your region. Nothing at night.
Every 15 minutes: solar covers your use first, the surplus charges the battery, the battery covers your evening, the rest is exported or imported. With 90% round-trip efficiency.
The same calculation runs on real smart-meter data in the WVE customer portal in the Netherlands: a virtual battery that follows a customer's measured 15-minute consumption for a month, with notifications and a report. Suppliers and installers can licence the engine for their own app, their own data and their own customers.
Free option: put the simulator on your own website in two minutes. Pricing for the engine starts with a pilot; software licence from € 995 per month including 100 simulations. We reply within two working days.