Hello from Sweden!
There is a good discussion ongoing on the topic of time-variable grid fees here. Status is (as I understand it) that Victron is working on implementing time-variable costs in the DESS. But I think that my question is slightly different:
We will get something similar to time-variable grid fees in 2026. The grid fees (meaning kr / kWh) will stay the same during the day, but there’s an additional fee for the average of three peak kWh/h readings each month. If I, for example, during three different hours this month pulled 4, 5, and 6 kWh from the grid (and less during all other hours), I would pay 5 * 45 kr in addition to the grid fees. This peak-fee is independent of the total energy used during the month.
In 2026, this fee will become time-variable and will be about 130 kr per peak kWh/h during weekdays and 0 kr during nights and weekends. This means I can save quite some money by avoiding high-consumption hours. I am therefore looking for a way to limit the total energy pulled from the grid each hour. This is not exactly the same as the peak shaving implemented in the ESS, as that limits the short-time power, not the hourly energy. Of course peak-shaving will limit the hourly energy as well, but I’m happy to allow higher peak power drawn under short periods.
It’s more a smearing out of the energy pulled from the grid that I’m after. If I by 12:40 notice that I’ve only pulled 0.5 kWh, but I’m averaging 2 kWh this month (or have set the 2 kWh target by some other heuristic), I can charge the battery during the remaining 20 minutes. Likewise, if I’ve pulled 2.1 kWh from the grid and it’s only 13:30, I would like to discharge the battery for the next 30 minutes instead of using the grid. Of course, making smart decisions becomes more complicated in combination quarterly energy prices.
Does anyone have an idea where I can even start? We have a 3-phase MP-II ESS setup with a 10 kWh battery, a Cerbo GX. I use HomeAssistant and I’m not unfamiliar with programming but I haven’t used Node.Red.
Thanks a lot for your help!