Dynamic ESS: Introducing fixed price slots of 30 minutes

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Barbara (Victron Energy) asked Jun 4, '24

Dynamic ESS: Introducing fixed price slots of 30 minutes

We are happy to announce that Dynamic ESS now supports fixed prices set to 30 minutes slots.

In countries like the UK, energy prices vary as much as every 30 minutes. To facilitate for this, you can now set up a fixed price schedule using half hours. To try this out, open Dynamic ESS settings in Victron on Beta VRM. Select fixed prices for selling and/or buying energy. Fill out a time slot for 30 minutes in which the price varies. From now on, your Dynamic ESS schedule for consuming, selling and buying energy will be adjusted to this entered schedule.

For UK users that use dynamic prices, we are still working on adding those. Expectancy is that this will be ready at the end of June.

Update 2024-06-17: We've moved this to regular VRM.

dynamic ess DESS fixed price uk

screenshot-2024-06-04-at-165843.png (57.7 KiB)

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Ants Kosmos commented · Jun 16 at 03:05 PM

In Estonia we have different taxes for day, night and weekends with dynamic electricity prises. Good to know if this possible use in formulas . :D

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Answer 1 · 2024-06-04T16:28:21Z

John Dent answered · Jun 04 at 04:28 PM

Ooo this is great news!

Out of interest, can the slots be filled in with a POST request?

I’m thinking some quick (and relatively dirty) Node Red flow to take Octopus’s 30 minute slots and post them into the VRM DESS web form.

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Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 06 at 07:15 PM

This should be possible from next week. I'll post an article then describing on how to do just that.

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John Dent Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 13 at 08:35 PM

Saw your article. It didn't precisely explain how to set the price slots, but it seems to work so I hope that's the intention. Great stuff — can finally teach DESS about Octopus Agile rates!

In case anyone is wondering, it's simply a matter of poking the Modify DESS config node with a payload of { "buyPriceSchedule": <new buy price schedule> }.

It grumbles if you give it an incomplete schedule, which is slightly annoying. So that means you have to install it at a time when you still have at least a full day's worth of 'runway'. (That or make up placeholder rates, which is a bit weird.) It is workable, even if not quite ideal. I'll report back if any issues.

Thanks!

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Dirk-Jan Faber (Victron Energy) ♦♦ John Dent commented · Jun 14 at 07:38 AM

Getting the JSON right might be a bit tricky, but that should indeed work.

We also got preliminary support for the dynamic prices of Octopus on our test setup since yesterday. Let me contact you directly to check if you want to be the first to run that.

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fellside Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 18 at 03:59 PM

Where can we find the article you mentioned?

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daniel-feist fellside commented · Jun 18 at 04:19 PM

Pretty sure it's this one: https://community.victronenergy.com/content/kbentry/293324/node-red-vrm-api-and-dynamic-ess-1.html

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Answer 2 · 2024-06-04T22:22:42Z

daniel-feist answered · Jun 04 at 10:22 PM

This is welcome progress, but I personally still find that DESS doesn't behave as expected and therefore isn't usable.

As a concrete example, my export tarriff is 15p 24/7 and between 23.30->5.30 my import tarrif is 7.5p but DESS "trade mode" doesn't:
- Sell to the grid prior to 23.30 even when it is clear there is a profit to be made given the upcoming cheap import tarrif.
- Fully leverage cheap 7.5p overnight import to charge battery when this is a no-brainer. Instead it relies on unreliable PV forcasts for the following day and only partly charges overnight (if at all). Then, if the sun doesn't shine as expected, it imports at 30p/kWh (four times the price).
- Prioritize charging battery with PV to cover evening forcast usage. Instead, it first exports and only later in the day charges the battery. This means that, if PV generation doesn't happen it will import in the evening at 30p/kWh when it shouldn't need too.
- Use only grid for consumption during cheap 7.5p rate. Instead it consumes from battery for some strange reason some of the time.

Before there was some discussion of some of the oustanding issues being tackled. But was there any progress on any of these?

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frantiseksobotka commented · Jun 05 at 08:23 AM

Hello, you are right. DESS is also from my point of view not usable.

Issues which are/were reported are still pendling and green mode neither node-red version not solved most of the problems till now.

I tried personally 4 different ESS optimizers. Victron DESS, Victron node red DESS, one optimizer made by Czech company and one made by Polish programmer, you can now him from this forum.

Unfortunatelly Victron DESS is the worst and best one which I am using is the optimizer from Piotr Maciejewski. It is a bit user unfriendly at the beginning, but when you have setup done, you don´t need any more daily or hourly babysitting of your system. Just setup and forget. With full control of all the parameters.

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daniel-feist frantiseksobotka commented · Jun 05 at 08:40 AM

I am also using gbboptimizer (I didn't see the Czech one though). Works great for me too, even though I agree it was initially somewhat complex. However, every time I see a DESS announcment I test it again just in case I'm pleasantly suprised. Every time though I see the same issues again. (I just added one more to the list above that happened last night)

If you are on fixed tariff, green mode is no different to using ESS + scheduled charge is it?

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frantiseksobotka daniel-feist commented · Jun 05 at 09:35 AM

Same for me :) I tried it yesterday and have to switch off after one hour.

DESS just finished 6kW grid feed in and just afterwards started to buy 6kW expensive grid to push it to battery during nice sunny PV 11kW production when over max 100% was predicted for afternoon.

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frantiseksobotka daniel-feist commented · Jun 05 at 09:41 AM

Yes, green mode is ESS with automatic charge at low price (which I do not need 10 month).

The biggest DESS problems for me are: unwanted feed-in followed by charging and not possibility to trade to defined SOC only and use rest ot battery till minSOC as buffer.

Both are solved at gbboptimizer.

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Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 06 at 07:37 PM

Lets see if we can get this working nicely for you then. First of all, I notice that on your site (assuming that is c0619ab38079) your currency still is set to Euro. Under Settings -> General -> Currency, you can set that to be Sterling.

The maximum import power and maximum output power are also set quite high, or at least higher than I would expect. What is the amperage of your main breaker?

Also your points 1 and 3 seem to clash. In order to mitigate point 3, you'd better switch the system to "green mode".

The system also needs a bit of run time (a few days) without too much tweaking. And your system hasn't been running long stretches for a while.

A colleague also took a look at your system to check why it didn't charge. And he did discover a bug in the system, when the sell price was higher than the buy price. He fixed and released that. So that shouldn't happen again.

Then about gbboptimizer. Feel free to switch to that if that works better for you. I don't mind at all (as long as you use Victron equipment, I am happy). I am personally perhaps a bit hesitant on letting a third party take control on my system. But I am probably more paranoid than most users.
But I did take a look at gbboptimizer a while ago and I found it quite complex to setup. The more settings you can do, will certainly help in getting the optimal results. With the VRM implementation we try to get the best results with minimal adjustments needed in a user friendly way.

Lastly about "outstanding issues being tackled". That is a bit of a general remark, so I'll answer it a bit generic too. We did close a lot of those tickets in the last months. So yes, there is progress and no, the todo-list isn't empty yet.

And please do keep reporting issues; the more concrete, the easier it is for us to look into and to find a cause and solution (dates, times and vrm ids help a lot on quickly troubleshooting). I try to read all messages and react to a lot of them. But as this is quite an active topic I am sure I'll overlook some posts. All time I spend on community is time I don't spend on coding.

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daniel-feist Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 06 at 09:34 PM

Appreciate your detailed response. Yes. c0619ab38079 is me!

Fixed euro->sterling, didn't find setting before.
Max import is 3x100A (three-phase). Max export (approved) is 22.1kW.
Max discharge is based on 4.4kW/phase. Max charge is more than 5kW, but I limited this before to be kinder on battery.
1 and 3 don't clash. They are different issues, they wouldn't happen on the same day:
- 1 is about selling for 15p in evening when you know you can buy back for 7.5p overnight. If you are in "trade" mode this should be obvious thing to do. This is more an issue in summer, in winter you would likely not have exess in evening with heating on (at least with my battery capacity).
- 3 is about the approach used to charge battery from PV to allow for evening usage. This is more important in winter/spring/autumn when there is less PV (and when cheap energy that charged battery overnight may have been used for heating). If DESS knows (based on forecast) that 50% charge is needed for the evening, it has a choice. Either i) charge to 50% from PV and then export ii) export and then charge to 50% in the late afternoon. Currently it is doing ii) and the risk of this approach is that weather may change, cloud might come out and it can't charge to 50%, and then import is required in the evening. It is best to take the more conservative approach and it reduces risk of expensive import and don't reduce profits. Others have also raised this.
Do you have any details on the bug, what it impacts specifcially and what release it will be fixed in? If the system was getting confused when sell price is higher than buy price that could explain a lot!!
I am open-minded as to different solutions. GbbOptimzer is definitely a steeper learning curve vs DESS and I avoided it for a long time. Eventually I took the time to onboard because DESS (previous versions) was actually loosing me money. That said, the reason I keep coming back to DESS and trying it again is because I really believe that Victron (via firmware updates and introduction of core functionality) has the ability to provide the best solution e.g. via min/max-setpoints etc. I'm not yet seeing this though.

I undestand progress is being made and that's great, this is really appreciated. Just since it came out of beta, there seems to be a less visibility of whats being improved/fixed and I wasn't sure if/when I should come back and re-test it.

I'm happy to keep DESS enabled for a few days without touching anything if you have someone looking at my install. It will be interesting to see how many of the 4 issues I mentioned are fixed by the bug you mentioned. The PV charge/export priority I thought you mentioned was in node-red version already, is this correct? When will this make it into VRM version?

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daniel-feist daniel-feist commented · Jun 07 at 05:08 PM

The plan looked better, so it seems the bug you mentioned is fixed. Although ideally:
- Discharge should happen later in the evening to be more conservative
- Discharge should be more gradual, not 11kW which is less efficient. (I can limit charge/discharge rate, but shouldn't really need to

BUT, in practice the there was was minimal discharge and the new plan now doesn't have discharge.

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daniel-feist daniel-feist commented · Jun 07 at 05:18 PM

OK. So it has now planned another discharge. No discharge though. Could this be another bug or an issue with my sytem?

How is the discharge implemented. Is it via ESS set-point or some other approach?

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daniel-feist daniel-feist commented · Jun 10 at 08:30 AM

So, @Dirk-Jan Faber (Victron Energy) I've been observing behaviour for the past couple of days and things look like they are now much better with the price bug fixed. I think bug probably resolved 1, 2 and 4 from my list of issues. A couple of observations/issues though:

- There are still occasions where grid import occurs when it shouldn't. It's not a significant amount and I'd expect this from basic/external controls. But DESS should be able to avoid this. Examples are 9-11pm last night and 8am this morning (10th June).

- I don't know if it's an issue with my system specifically, but the planned discharges (seen in screenshots above) simply doesn't happen as planned. On some days (e.g. yesterday) I do see some discharge happening, but it seems it's not working as expected.

- Planned discharge is sometimes early than it needs to be (less conservative) and very aggressive rather than spread out over time. (Although, I haven't seen this aggressive discharge happen yet due to a potential issue)

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daniel-feist daniel-feist commented · Jun 12 at 08:39 AM

Actually 4) isn't fixed. As during the night, when planned discharge fails, it is often using the battery. If we can workout why the planned discharge doen't work, this might resolve this.

(11th June 2024)

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Dirk-Jan Faber (Victron Energy) ♦♦ daniel-feist commented · Jun 12 at 05:58 PM

Just to be sure. You mean that this blue predicted feeding between 2:00 and 3:00 is probably not going to happen?

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daniel-feist Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 12 at 09:02 PM

Yes, this doesn't happen (you can look at previous days too). And in the period where discharge doesn't happen it often uses battery.

There is also discharge problem in the evening, where plan wants to emply battery before 11.30-> cheap rate (given export available profit), but the planned discharge just doesn't happen. or only small amount happens. You can see this in my screenshots where I show what was planned and then what happpened.

I don't know how discharge is controlled (via ESS setpoint or something else?) but it's clearly not working for me. Don't know if this is general DESS issue or something specific to my install.

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Dirk-Jan Faber (Victron Energy) ♦♦ daniel-feist commented · Jun 13 at 06:22 AM

We'll look into it. It sure helps that it is consistent.

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Dirk-Jan Faber (Victron Energy) ♦♦ daniel-feist commented · Jun 13 at 04:53 PM

There is a restriction logic: if the sell price is at its minimum, then disable discharging to grid (mirror logic to disable charging when buy price is maximum).This rule is now showing its undesirable effect. It seems with a lot of our decisions really had the unsaid bias of buy price always being above sell price.
So your situation is kinda rare, where the sell price is above the buy price.
We'll adjust the logic to better handle this and hope we don't introduce new side-effects. I'll update once we role the fix out, which will hopefully be tomorrow.

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daniel-feist Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 13 at 05:04 PM

This may explain why dischage at night isn't working, but it doesn't explain why evening discharge doesn't work!

How is discharge supposed to work? By adjusting set-point, or some other mechanism?

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Dirk-Jan Faber (Victron Energy) ♦♦ daniel-feist commented · Jun 13 at 06:04 PM

True, but I'd like to solve one issue at a time. And, while the discharge in the afternoon is a lot less as first predicted, it isn't zero either.

Discharging is indeed done by adjusting the set-point, but not where you probably expect it to be. It is located under com.victronenergy.hub4, path /Overrides/Setpoint.
You can check the source code here.

You can already check the /Overrides/MaxDischargePower path of com.victronenergy.hub4 to see if that is set while it is discharging in the afternoon. To be honest I doubt that is causing it, but that is the first thing to check.

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daniel-feist Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 13 at 09:47 PM

In the evening "MaxDischarge" is being used and constantly updated preventing discharge.

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Dirk-Jan Faber (Victron Energy) ♦♦ Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 14 at 09:31 PM

Bit late update, but today we implemented a fix for this. At the moment it is only applied for your site id. If it works as intended for a few days, we put it in for everyone that has higher sell price than buy price.

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daniel-feist daniel-feist commented · Jun 13 at 08:44 AM

Here you can see dischrge at 1-3am didn't happen. Also it consumed from battery rather than grid. You can also see it's planning discharge at 5pm so that battry reaches 20% by 11.30pm. This doesn't/won't happen either, and last night battery was at 65%, rather than 20%. (planned discharge should ideally also be less aggressive and not all in 1hr)

TODAY

YESTERDAY

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Dirk-Jan Faber (Victron Energy) ♦♦ daniel-feist commented · Jun 21 at 04:41 PM

We adjusted the logic on setting the restriction, which should resolve the issue of not discharging. Please check during the weekend and let us know if it now works correctly (I'll check again on Monday too).

Do note that your contract is really special. It really isn't that logical that the sell price is above the buy price. You'd almost be tempted to pull a cable from you neighbours house (if he has the same contract) and directly feed that energy back to your grid, splitting the money you make.

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daniel-feist Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 21 at 04:55 PM

Great, I will monitor and report back.

Have the team also looked at the issue with weird target SoC and discharge rates during discharge period? My battery size is currently set 32kWh (actual size is 28.6kWh) and the weirdness was still happening. Did you find a bug with this? Can/should I put battery capacity back to what it was or do I need to increase this further?

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Dirk-Jan Faber (Victron Energy) ♦♦ daniel-feist commented · Jun 21 at 05:01 PM

Afaik we are still looking into finding the cause. I'll check and provide an update on that on Monday.
Meanwhile, please leave it set to 32 kWh.

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daniel-feist Dirk-Jan Faber (Victron Energy) ♦♦ commented · Jun 21 at 07:02 PM

I'll leave battery at 32kWh, I'l need to leave the 7.5kW inverter power limit in place though, because otherwise (with this bug) it ignores the 7.5kW in DESS and drives inverters at full power making lot of noise in the middle of the night.

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daniel-feist daniel-feist commented · Jun 24 at 12:15 PM

It's behaving better, but still not great:

Discharge rate is not controlled in most cases and exports at up to 14kW which is not at all desirable when i) it is not required ii) 7.5kW limit has been configured.
Discharge to grid doesn't always happen in the evening, which would be the most conversative approach to avoid of import, instead it's more eager and trusts forcast a bit too much. (similair issue in winter with trusting PV forcasts and exporting before charging battery)
Planner seems to plan to hit minimum 10% at 23.00 or 23.30. It would be ideal to have at least some margin in place. That said, if the algoritm for 2) was improved a margin may not be requied. EDIT: This could also be a side effect on my battery (28.6kWh) being smaller than DESS thinks it is (32kWh), based on what you asked me to configure.

On a seperate note is there any information anywhere to help better understand how DESS now it has been significnalty improved? I can understand part of it from looking at code your shared, but things like this would be really interesting (and helpful) to understand):

How often is it re-planning?
What data is sent/returned as part of updating the plan?
What are the primary stategies used locally and when are they employed?

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daniel-feist daniel-feist commented · Jul 03 at 09:58 PM

@Dirk-Jan Faber (Victron Energy) Do you plan to look into this any further? If you need my system to test then I can leave DESS enabled, but otherwise I will turn it off. For the two reasons I mentioned above:

- Uncontrolled discharged rate.
- Discharge to grid (for trading) is over-optimisitc and ends up importing at expensive rate (for no need) between 10-11.30pm.

I could try putting the battery size back to 28.6kWh to see if this helps with second problem (maybe it things there is more left in the battery than there is). But, you had asked me to leave it at 32kWh while debugging the first issue, remember..

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Answer 3 · 2024-06-17T10:24:01Z

Galin Radoslavov answered · Jun 17 at 10:24 AM

Hi,

This is a good new BUT when you will fix the diagram for BULGARIA?

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Dynamic ESS: Introducing fixed price slots of 30 minutes

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