Time of use Tariff


I am currenlty implementing a time of use tarrif provider that has different prices for feed in and feed out (so buying and selling of energy) but looking at the interface openEMS does not have/account for that. Is this intended and if so how do i tell the system that buying is expensive but selling is negative for example?

Hi @nlamarti,

indeed there is currently no separate “Sell-To-Grid Tariff” (I am not sure about the correct technical term) API defined in OpenEMS, but only a dynamic “Buy-From-Grid Tariff”.

This is something we have in mind, but as there is currently no legislation here in Germany that would incentify this, there has not been any development yet.

Can you give some more insight?

  • What is the application you are trying to develop?
  • For which market are you developing it?
  • Can you point me to the API of the provider?

Thanks & Regards,

Hi Stefan,

sometimes in Germany aswell the Tarif (of for example Tibber) is negative. In such cases it would be great that the EMS knows that it is okay to charge the Storage or to not discharge it if it is not allowed in Germany to charge it from the Grid.

How are such cases handled right now in the Tibber Impl ?


@Sn0w3y I am also Tibber user (see https://www.youtube.com/watch?v=RQ9Xt474d-c). Real negative prices (not only the electricity price, but also transmission costs etc.) are very seldom in Germany; but even though this would be already coverred.

Charging a battery from Grid is already in development and field test in Sweden: Implementation of new Time of Use Tariff controller by venu-sagar · Pull Request #2238 · OpenEMS/openems · GitHub; developed by @venu-sagar for FENECON.

This thread is actually about “time variable feed-in-tariffs”. This is something we already see in Germany in “Direktvermarktung”, but I have not seen it till now combined with “time of use tariffs” (“zeitvariabler Netzbezugspreis”).


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I’m actually looking at the same thing.
I’m in Belgium and using the Entso-e prices.

I’ve adapted the TimeOfUseEntsoe code to include markup costs. I’m still finishing the code and cleaning it up, but should initiate a PR soon.

For buy from grid I need to add:
-commercial margin taken by my energy provider (ENGIE in this case)
-vat: 6% in my case
-all sorts of taxes issued by the government.

For injection, it’s the base Entso-e day ahead price.

Ideally I’d like to dynamically charge/discharge the battery based on the difference of those prices so I cannot only optimise self consumption, but also “turn a profit” by charging and discharging the battery at the correct time.

Any pointing in the right direction is appreciated