Tariffs & forecasts

Tariffs and forecasts are the data that drives cost-optimised and CO₂-aware charging, plus the statistics. evcc distinguishes four kinds:

Grid price (grid): what you pay per kWh drawn from the grid.
Feed-in price (feedin): what you get paid for exported solar energy.
CO₂ intensity (co2): how much CO₂ per kWh of grid power — the basis of CO₂ mode.
Solar forecast (solar): expected solar production for plans and battery control.

Tariff kinds

For grid and feed-in pricing, three kinds are common:

Fixed price: A constant price per kWh. Fits most standard contracts.
Time-based price: A base price plus fixed zones across weekdays, hours, or months. Use this for day/night tariffs, summer/winter rates, or night-time meter setups.
Dynamic / market price: Hourly spot-market prices pulled from an external provider (e.g. Tibber, aWATTar, Octopus, Energy Charts). Required for automatic charging during cheap hours.

You can also bring your own custom data sources — via HTTP, MQTT, scripts, or Modbus. See User-defined and the tariff reference.

Forecasts

CO₂ intensity comes from external services like Electricity Maps or Grünstromindex. Solar forecasts come from providers such as Solcast, Forecast.Solar, or Open-Meteo — usually based on your system parameters (location, orientation, power).