question

Michelle Konzack avatar image
Michelle Konzack asked

Cerbo GX, Venus OS Large and Nordpol

Good evening,

I have a new customer which will get 200kWh of batteries with three MultiPlus-II 48/5000 he has currently a Grid connection with 25A and is allowed to feed in up to 15kW.


However, he only want to feed in, if the Energy price is above 18¢/kWh, e. G.

----8<----------

Teavitame Teid, et homne elektrienergia börsihind ületab Teie poolt seatud hinnahäire piiri 18.00 senti/kWh (koos käibemaksuga) 21.08.2023 järgnevatel tundidel:

07 - 08: 42

08 - 09: 39.011

09 - 10: 65.99

10 - 11: 30.01

11 - 12: 57.962

12 - 13: 30.011

13 - 14: 30.008

14 - 15: 30.006

15 - 16: 41.27

16 - 17: 36.005

18 - 19: 36.005

19 - 20: 65.994

20 - 21: 30.008

21 - 22: 24.527

22 - 23: 20.28

----8<----------


Good that I am Off-the-Grid and save me the headaches.


Is there an option to use the Nordpol API for the feed in?


We need to configure the System in that way, that

1) first come the selfconsumption

2) charging the battery

3) if SOC=>95% Feed-In surplus energy.

4) if Energy price is higher then e.G. 18¢/kWh Feed-In until SOC reach 40% (better would be a algorithm, which select from the Nordpol list the most suitable time to Feed-In.


Since I have currently only a ColorControl GX, I can not play around with the Venus OS Large and depend on your suggestions and ideas.


Thankyou from Estonia

Michelke


feed-innordpol
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2 Answers
matt1309 avatar image
matt1309 answered ·

You can do this using Node red assuming your energy provider has an API. I believe a lot of people in the UK have done similar with octopus energy.


Node red will allow you to set all sorts of custom criteria, like you said based on SoC etc.

I'm not sure if there's a better way but I personally would get node red to query Energy Provider api (using HTTP node within node red).

Then use a switch node to check if price < defined number

Then use more switch nodes to check if > 40% SoC (may also want to check various other things like current loads)

Or if you want more complex logic just use a function in node red (it's javascript based).

Then if all criteria met for exporting then I would adjust the grid set point in ESS settings so that the power is exported.

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Michelle Konzack avatar image Michelle Konzack commented ·
Thankyou.


My provider (Eesti Energia) does not have its own API and direct peoples to use the Nordpol API since the Feed-In is based on the bourse price anyway.


However, i can also spider the EMail i get every day, if the price is above a customised limit (I have set it to 18¢/kWh.


I do not know how to program JavaScript. Only Asembler, C and PHP.


However, since the Feed-In prices are fixed one day before, i can calculate in the night before basrd on the SOC and predicted weather forecast how much i can feed in and creste somehow an algorithm which drop feeding in even at 30¢/kWh if I can sell the same day with e.g. 50 or 60 ¢/kWh.


Maybe there is someone who has done this already and is willing to share the code.

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matt1309 avatar image matt1309 Michelle Konzack commented ·
If you've got C then js will be no bother but the below link from @luphi looks promising
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luphi avatar image
luphi answered ·

Have you seen this: https://github.com/victronenergy/dynamic-ess


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