Your day
Scroll through a day at your home
The scene follows your scrolling. Every number comes from your own inputs.
France
Typical values for France
Starting values only. Your bill is the source of truth: enter your own import and export price in the simulator above.
| Typical import price | € 0.22 – 0.27 per kWh all-in |
|---|---|
| Export | Obligation d'achat, roughly € 0.10 – 0.13 per kWh for surplus |
| Solar yield | about 1,000 – 1,400 kWh per kWp per year, north to south |
| Battery prices | about € 600 – 900 per usable kWh installed |
Questions
Good to know
Autoconsommation avec vente du surplus or sans?
The simulator models self-consumption with export of the surplus. Enter the surplus purchase price as your export price.
Does the prime à l'autoconsommation count?
Yes, subtract it from your solar cost per kWp in the advanced fields.
Heures creuses?
Off-peak tariffs are not modelled yet. They can make a battery more useful; treat the result as conservative.
Other countries: NetherlandsGermanyBelgiumUnited KingdomIrelandSpainItalyAustriaSwitzerlandAustraliaUnited StatesSouth Africa all countries
Start here
Three questions, then your year
Each answer changes the picture right away. You can refine everything later in the full simulator.
How much electricity do you use per year?
Or use your real meter data
Upload the export from your smart meter or energy app (CSV). It stays in your browser; nothing is sent anywhere.
Where do I get this file?
- Netherlands: a P1 reader app (HomeWizard, Enelogic, Slimme Meter Portal) exports 15-minute or hourly CSV. Your grid operator's site only gives daily totals; that is not enough.
- Belgium: Fluvius "Mijn verbruik" → download kwartierwaarden (CSV).
- Germany: your Messstellenbetreiber portal or a smart-meter gateway app; Tibber, Octopus and Rabot show downloads in the app.
- UK: Octopus (Account → Download data, 30-minute), or any supplier with a smart meter; also n3rgy.
- Australia: your retailer or distributor portal (30-minute interval data; NEM12 files are not supported yet).
- Anywhere: two columns are enough: date-time and kWh per interval. Readings in watts or cumulative meter readings also work.
No file yet? Try the sample file to see how it works.
What is on your roof, or what could be?
What do you pay, and what do you get for export?
€
€
you pay (all-in)you get for export
Your year
Twelve months, where your power comes from
The simulator
The full simulator
Every setting, including yield and investment costs. Change anything; results, your day and your year update instantly.
Today, grid only
€ 1,050
electricity per year
With solar
€ 455
saves € 595 per year
Solar + battery
€ 181
battery adds € 274 per year
Self-sufficient
68%
of your use from your own roof
Solar used at home
63%
rest is exported
Payback solar
7.6 yr
€ 4,400 invested
Payback battery
11.6 yr
€ 3,000 invested
Which battery size pays off?
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 |
|---|
Compare two set-ups
Your set-up against an alternative. Move the alternative to answer the real question: which one.
| Per year | Yours | Alternative |
|---|
How it works
A whole year, every quarter of an hour
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.
Step 1
Your consumption
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.
Step 2
Your solar roof
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.
Step 3
The battery decides
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.
Assumptions and limits
Honest numbers, not a sales pitch
What we assume
- Battery usable between 10% and 100%, power 0.5 × capacity, 90% round trip.
- Solar shape for mid-latitudes; your yield per kWp sets the total.
- Prices stay flat over the years; no inflation, no degradation, no subsidies.
- Payback = investment ÷ yearly saving, before interest.
What it does not do
- Hourly prices follow one real past year (2025 wholesale market), not a forecast; available for NL, DE, BE, FR, AT, IT, CH, PL, Australia (New South Wales) and the US (California).
- No electric car, heat pump or grid services (peak shaving, trading).
- No taxes, levies or feed-in rules beyond the two prices you enter and the export rule.
- Standard profiles, not your smart-meter data.
What makes it accurate for you
- Use the all-in price you really pay per kWh, from your bill.
- Use the export price your supplier really pays.
- For a quote, ask an installer to check roof orientation and shading.
- Want it on your own measured data? See below.
For energy suppliers, installers and platforms
Put this engine in your own app
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.
- Rule-based, explainable calculations with visible assumptions. No black box.
- Runs on your side as a module, or as an API hosted by us.
- White-label: your brand, your currency, your tariffs, your languages.
- Proven in production with Dutch households since 2026.
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.