Export rules, prices and sunshine differ per country, and so does the answer. Pick your country for starting values and a short explanation, then enter your own tariff.
Net metering until 31 Dec 2026, then a feed-in fee of roughly 1 – 8 cents per kWh
EEG feed-in tariff, roughly € 0.08 per kWh for small roofs
Injection tariff of roughly € 0.03 – 0.06 per kWh with a digital meter
Smart Export Guarantee, typically £ 0.04 – 0.15 per kWh depending on supplier
Clean Export Guarantee, roughly € 0.18 – 0.24 per kWh
Obligation d'achat, roughly € 0.10 – 0.13 per kWh for surplus
Compensación de excedentes, roughly € 0.05 – 0.08 per kWh, capped per month
Ritiro dedicato, roughly € 0.08 – 0.12 per kWh
Market-based feed-in, roughly € 0.05 – 0.10 per kWh (OeMAG or supplier)
Set by the local utility, roughly CHF 0.05 – 0.12 per kWh
Feed-in tariff, often A$ 0.02 – 0.08 per kWh
Net metering in many states; net billing at $ 0.03 – 0.08 per kWh in others (e.g. California NEM 3.0)
Often not paid; some municipalities credit roughly R 0.70 – 1.00 per kWh
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.