with dynamic electricity prices from the EPEX day-ahead, ESS already has a strong foundation for smart load shifting and cost optimization. However, a new factor is coming into play: dynamic/variable grid fees.
These fees vary depending on grid load and time of day. That means the “true” cost per kWh is not just the spot market price, but rather spot price + grid fee. Optimizing only by exchange prices might soon miss part of the picture.
This is not only relevant in Germany. Other countries are also introducing or already applying variable grid tariffs – for example Sweden, Norway, the Netherlands, parts of the UK,
For example:
it would much more often pay off to charge the battery during cheap/low-fee hours and discharge it during peak hours.
The actual cost difference for running large loads (heat pumps, EV charging, storage cycles) could be far greater once both elements are included.
My prices in western Germany are
0:15-5:59 — 2,65 ct/kwh
6:00-15:44 — 6,63 ct/kwh (standard)
15:45-20:29 — 8,30 ct/kwh
20:30- 00:14 — 6,63 ct/kwh (standard)
That’s why I think it could be very interesting if Victrons DESS did not only integrate dynamic exchange prices, but also considered dynamic grid fees in its optimization logic. This would allow for more precise cost savings and closer alignment with how future tariffs are structured.
My question: Do you think Victron could implement such a calculation within DESS in 3.70?
Certainly not within any version of the Venus. However, you were present at the discussion with @Barbara . She promised that this will be implemented in the VRM soon. That they were working on the VRM’s new outfit first.
I think the combination of the exchange electricity price and the temporarily reduced grid fees makes it so attractive to charge during the cheaper times and bridge the more expensive times.
Overall, DESS would be able to operate much more efficiently.
Yep. I find myself a bit frustrated about this. Maybe nobody from Victron dev team has dynamic grid fees? For people who have them, it’s an obvious missing feature.
I’m also frustrated by this issue. I’m also disappointed that this problem, which from my layman’s perspective would be relatively easy to solve (time-varying component in the pricing formula), is still occurring. But I find the insinuation that it’s because the developers aren’t personally affected to be outrageous. @Barbara explained that the priorities were on the new layout and that it can be implemented better with this new layout. Furthermore, I think that implementing the 15-minute price intervals required some effort. I think the problem of time-varying prices is understood, and @Barbara has promised a timely solution. We should hold Victron to this statement.
Flexible network tariffs are also already in the test phase in Austria. They have already been activated on a trial basis in some households, including ours. It’s really time for Victron to finally implement this!
Here in Germany, they’ve been available as an option for a few months now; in my area, they can account for one-third of my electricity costs. My home storage, wallbox, and heat pump are all designed for this. Only the integration of DESS is still missing. That’s a shame, but hopefully, that will change soon.
Excluding taxes, electricity vs. grid costs were 24% vs. 76%.
June was a cheap-kWh month and shares vary across the year, but as my system grows and becomes more efficient—and as I add more batteries — grid fees account for a larger share of the bill.
For context: we knew we were changing the design of the Dynamic ESS configurator, and we wanted to prevent our team spending time building this feature in the old configurator and the new one.
I’ll update the beta-vrm side of community as soon as the change goes to BETA, and in this community category you’ll find my update when it goes live!
I recommend adding a second variable “gf” as greed fee or “tc” as time based constant, which get time based values.
This can be integrated into the main formular.
That way the formulas does not need to be copy’n pasted and adjusted several time for a day.
Real example for Hamburg:
00:00-00:30 standard 12,11ct/kWh
00:30-07:00 low 4,84ct/kWh
07:00-17:15 standard
17:15-21:00 high 16,25ct/kWh
21:00-24:00 standard
The timeslits and prices are fixed for 3 months.
The Victron-suggested formula-hours based system is more flexible though. For example, imagine if you have a contract with zero price “EV charging” hours, and the rest of the day with dynamic pricing. And maybe some hours with low/high grid fee as well.
Anyway, I am very happy to see progress on this! Thanks Victron.
Thanks, Barbara, that’s really good news. How you implement this is secondary to me personally. The main thing is to make it simple enough that it doesn’t cause any other problems and flexible enough to be usable for all the conditions of all our European neighbors. From my regional perspective, three different daily periods are sufficient, but I know of other regions in Germany where there are only three daily rates (high rate, standard rate, low rate), but these rates apply at six different times a day. Thanks for your work… to the entire team.
