Automatic solar reduction during negative export pricing

[herbi3]

Getting charged to export to the grid isn't quite ideal, especially when there is no control over what the inverter is doing.

Luckily, Solaredge inverters support TCP Modbus, and I am able to send the command to the inverter to ZERO export (solar production matches consumption only) this helps the grid reduce its surplus requirements and I also don't get charged to export.

This setup, I run a ubuntu virtual machine, using emoncms as a service, a custom script to pull pricing from amber API, and another custom script that polls both solaredge inverters and pulls data from all of the registers (production, consumption, export etc.)

All of the data is posted into InfluxDB via telegraph (mqtt plugin, connecting to the emoncms mqtt as its source) - within emoncms after setting up each feed, I have each one then publish to its own mqtt server, which telegraph picks up and ships it to the influx database. Then visualised with Grafana.

If anyone else has the same inverters and meter attached, I am more than happy to help duplicate this setup. you'll need your own amber api key, hardware etc. Solaredge TCP modbus is now available for setapp enabled inverters, over secured WiFi, it just needs to be enabled by directly connecting to the inverter.

Here is the automated dashboard, there are x3 publicly available - just select different ones from the top left of the page

[tjc998]

Looks very cool. Modbus does seem to be a much more responsive way of getting data than by polling their API.
Do you have a link to the modbus register map?

[herbi3]

The result is instant, as the amber api is polled every 10s or so to get the real-time price

I’m using this great tool by nmakel here

https://github.com/nmakel/solaredge_modbus

Writing data to some registers is still be worked on

[purcell-lab]

I'm very interested in this functionality as well.

I originally enrolled my solar inverters in SmartShit with the hope that Amber could automate the zero export. Unfortunately the SmartShift solution ended up resetting the SolarEdge inverters and not switching to zero export so Amber had to switch off that functionality and have a firmware fix underdevelopment with SolarEdge.

In the meantime I have been trying to setup zero export locally via SetApp, but every time I change my export values they switch back to defaults after 30 seconds. SolarEdge support have said this is because my inverters are enrolled in (Grid Services) external control via SmartShift. So I'm in the process of un-enrolling my solar inverters from SmartShift so I can enable local control of zero export. Note, my battery (Powerwall2) remains enrolled in SmartShift because that is working well.

With SolarEdge inverters there is also the need to change the AdvancedPwrControlEn register to on, which I presume I could do with a ModBus call as I don't seem to be able to do that with SetApp.

[herbi3]

That’s a good point, I found when reading the AdvancedPwrControlEn via modbus, it was already enabled on both of my 10kwh threephase inverters (follower was probably set from the master inverter). I haven’t yet been successful in changing that status via modbus just yet - the reading of that register seems to be different when writing back to the register.

[wh0phd]

2 weeks later — did you have any luck @herbi3 ?

[herbi3]

@wh0phd - not yet, since it’s already enabled this setting for me so far at least, won’t be needed to change often. It can be changed anyway via going directly through the inverter web gui too, so it’s not essential to be included (yet)

[wh0phd]

I just had a look around the web GUI — sorry where is this setting to change?

[herbi3]

@wh0phd - it was already enabled when RRCR was changed (that’s what I noticed at least). What does the register say when you read the data from the inverter? Was yours already enabled by default too?

[tux43]

I’ve done something very similar after being a customer for about a month. I have skills with Home Automation and have managed to do a few things that you might find interesting.

My setup:-

• 7.8kW of Solar Panels with 6kW inverter
• Electric Vehicle
• No battery (yet!)

Functionality achieved:-

• When solar feed-in tariff is negative spin down the inverter to only cover household demand (TCP/IP connected modbus inverter required)
• Maximise Electric Vehicle charging by using only surplus solar power when the feed in tariff is negative
• Spin down the inverter to 0W output when power prices go negative plus activate high load appliances such as EV charging, Air Conditioner, Hot Water, Flood Lights, Pool Pump etc…
• Turn off appliances when prices surge above $1kW/h, reenabling after surge has subsided
• Set your own off-peak & peak thresholds so dishwasher, washing machines etc… run during favourable times
• [Battery could be discharged to the grid when price hit a threshold. I haven’t tested this however relatively easy.]

[purcell-lab]

I have skills with Home Automation and have managed to do a few things that you might find interesting

I would be very interested so see how you have implemented these automations, can you share your automation scripts?

Here are my automations in Home Assistant:

https://community.home-assistant.io/t/running-devices-when-energy-is-cheaper-and-greener/380011?u=markpurcell

[tux43]

Sure, I did a bit of a writeup here - https://community.home-assistant.io/t/automate-fronius-soft-limit/465124/6 I am happy to share anything that might be missing.

[tux43]

I’ve done something very similar after being a customer for about a month. I have skills with Home Automation and have managed to do a few things that you might find interesting.

Update: I've had a couple of days where this worked very favourably, allowing me to charge EV during times where power cost was <= $0!

You will see in the below graphs that the majority of my usage was when cost is $0. This makes Amber great!!

[purcell-lab]

I managed this for the first time this week.

Set my solar inverters to zero export and it curtailed my solar production to meet my household load.

[purcell-lab]

Here is my Home Assistant automation.

alias: Zero Export Automation
description: ""
trigger:
  - platform: numeric_state
    entity_id: sensor.amber_feed_in_price
    below: 0
  - platform: numeric_state
    entity_id: sensor.amber_feed_in_price
    above: 0
  - platform: numeric_state
    entity_id: sensor.amber_general_price
    above: 0
  - platform: numeric_state
    entity_id: sensor.amber_general_price
    below: 0
condition: []
action:
  - choose:
      - conditions:
          - condition: numeric_state
            entity_id: sensor.amber_feed_in_price
            below: 0
          - condition: numeric_state
            entity_id: sensor.amber_general_price
            above: 0
        sequence:
          - device_id: 8e8f45345219e32b8a645ce8dfb767c3
            domain: select
            entity_id: select.solaredge_i1_limit_control_mode
            type: select_option
            option: Export Control (Export/Import Meter)
          - device_id: 8e8f45345219e32b8a645ce8dfb767c3
            domain: number
            entity_id: number.solaredge_i1_site_limit
            type: set_value
            value: 200
      - conditions:
          - condition: numeric_state
            entity_id: sensor.amber_general_price
            below: 0
        sequence:
          - device_id: 8e8f45345219e32b8a645ce8dfb767c3
            domain: select
            entity_id: select.solaredge_i1_limit_control_mode
            type: select_option
            option: Production Control
          - device_id: 8e8f45345219e32b8a645ce8dfb767c3
            domain: number
            entity_id: number.solaredge_i1_site_limit
            type: set_value
            value: 0
    default:
      - device_id: 8e8f45345219e32b8a645ce8dfb767c3
        domain: select
        entity_id: select.solaredge_i1_limit_control_mode
        type: select_option
        option: Disabled
mode: single

[herbi3]

@purcell-lab - did you get a response on the inverter resetting issue from amber? even though now you are out of Smartshift integration

[herbi3]

thanks @purcell-lab - with the DC coupled batteries, they charge directly from the panels so setting to zero export, the batteries will continue to charge from excess solar available.

for your power wall, I can think of a way in python with emoncms as the database to automate the export limit value. it'll just check the current battery charge % and only apply the site limit value to 0 once the battery % reaches above 95% for example. however, it would have to not change the site limit value too often, because each time this value changes, the inverter drops out for around 30s as it re-initiates to the new site limit value. within the script, I would have it apply just once when prices are negative, and then change the value to a hard 0 once the battery % is over 95%.

I only use emoncms as the database and value processing so I can combine multiple values easily and post as one object. it also gives me a local API to be able to read the data out of the emoncms database.

I have configured homeassistant also, but my goal of HA is to use it as an in home display so everyone can disable or enable certain virtual switches, which then my python services adjust the junctions to suit whatever has now been enabled or disabled.

before switching to Amber, I had a virtual switch to change between amber live pricing and origin pricing. when the switch was changed to amber pricing, the solar curtailment was automagic and it would dynamically switch the relay for the hotwater heating (with the scripts overall goal to only heat from solar to a limited daily 15kWh limit, then forced off. on overcast or raining days, the hotwater would switch on for three hours starting at 2pm until 5pm) - If there was a Smartshift API available, I would change to the Smartshift API, as my current python services aren't "smart" in the sense of knowing how to correctly handle the pricing forecast.

Ultimately before Amber, my automations were based on amber pricing, so the virtual switch was needed so I could maximise the invoicing from Origin.

[herbi3]

@purcell-lab - I also did have x2 10kW three phase inverters, but within the last couple weeks I changed these to x3 10kW single phase inverters purely so I could have x3 solaredge batteries installed. I was told the three phase inverters were hybrid, but when it came to crunch time for the battery installed, solaredge came back and said the current DC batteries aren't compatible / approved in Australia, so they upgraded all inverters for me at their cost. its a small amount for them, but when I am spending nearly $40k on batteries, it was certainly in their interests to provide a free upgrade.

Now with the single phase inverters, I have blackout protection on two phases (no, I don't have any three phase AC or devices so rotational offset between each phase isn't a concern (yet)) - during blackout, the batteries continue to charge from whatever is available through the panels while also keeping the house running. if we lowered our consumption to necessary devices only, we could theoretically run in blackout for a few days, if not weeks given the sun is shining!

[purcell-lab]

@purcell-lab - I also did have x2 10kW three phase inverters, but within the last couple weeks I changed these to x3 10kW single phase inverters purely so I could have x3 solaredge batteries installed. I was told the three phase inverters were hybrid, but when it came to crunch time for the battery installed, solaredge came back and said the current DC batteries aren't compatible / approved in Australia, so they upgraded all inverters for me at their cost. its a small amount for them, but when I am spending nearly $40k on batteries, it was certainly in their interests to provide a free upgrade.

Very nice setup, when I was getting my system (12 months ago) I was really on fence for which type of batteries. I liked the look at control that solaredge were promising, but ended up with SolarEdge 3 phase inverters and AC coupled powerwall.

Now with the single phase inverters, I have blackout protection on two phases (no, I don't have any three phase AC or devices so rotational offset between each phase isn't a concern (yet)) - during blackout, the batteries continue to charge from whatever is available through the panels while also keeping the house running. if we lowered our consumption to necessary devices only, we could theoretically run in blackout for a few days, if not weeks given the sun is shining!

Blackout protection wasn't a priority for me so I was happy to manage the risk (I'm sure if I need it I may consider otherwise).

The powerwall is a nice product but the controls inside the walled garden are frustrating. Things are getting a little better with both local and cloud APIs maturing and offering the same functionality as the Tesla app, but really only set SOC %, Backup, Self-Consumption and Time Based Control modes available. A discharge mode would be wonderful, but not currently available. The US seems to have lots of restrictions on grid exports which I guess is where Tesla are taking their cues
.

[purcell-lab]

Looks like we have a bit to talk about...

thanks @purcell-lab - with the DC coupled batteries, they charge directly from the panels so setting to zero export, the batteries will continue to charge from excess solar available.

One of the real advantages of DC coupling, also being able to oversize your array and battery without worrying about grid export restrictions.

for your power wall, I can think of a way in python with emoncms as the database to automate the export limit value. it'll just check the current battery charge % and only apply the site limit value to 0 once the battery % reaches above 95% for example. however, it would have to not change the site limit value too often, because each time this value changes, the inverter drops out for around 30s as it re-initiates to the new site limit value. within the script, I would have it apply just once when prices are negative, and then change the value to a hard 0 once the battery % is over 95%.

Delaying the setting the export limit to 0W until the SOC is over 95% is a good way to avoid the small leakage and also sometimes the SolarEdge inverters move too quickly and I can curtail earlier than I would like. Delaying setting the export control should be straight forward in Home Assistant automation as well.

With EMHASS I get a couple of signals for what to do with the battery, I graduate my charging schedule. If I set the backup reserve over my current SOC it will charge from solar/ grid at 5 kW, if I put into backup mode it will charge at 10 kW. So I have two automations, everytime the forcast SOC changes, I set the backup reserve to follow and if my forecast battery charge is > 10 kW, I also put into backup mode.

You can see the powerwall charge chasing and following the SOC forecast:

I haven't seen the inverter resetting when I change backup reserve, what would I be looking for.

I only use emoncms as the database and value processing so I can combine multiple values easily and post as one object. it also gives me a local API to be able to read the data out of the emoncms database.

I have configured homeassistant also, but my goal of HA is to use it as an in home display so everyone can disable or enable certain virtual switches, which then my python services adjust the junctions to suit whatever has now been enabled or disabled.

before switching to Amber, I had a virtual switch to change between amber live pricing and origin pricing. when the switch was changed to amber pricing, the solar curtailment was automagic and it would dynamically switch the relay for the hotwater heating (with the scripts overall goal to only heat from solar to a limited daily 15kWh limit, then forced off. on overcast or raining days, the hotwater would switch on for three hours starting at 2pm until 5pm) - If there was a Smartshift API available, I would change to the Smartshift API, as my current python services aren't "smart" in the sense of knowing how to correctly handle the pricing forecast.

I would suggest you have a look at the Home Assistant addon EMHASS, its a python module so you will feel right at home and the level of scheduling optimisation and control you would be able to achieve would outperform SmartShift as you can tune it to your site and you can also control your other loads (like DRED AC) for an even bigger impact. As you may know SmartShift is also based on a Linear Programming model, but without the level of end user control that is enabled by your own local instance. I have EMHASS and SmartShift running in parallel which allows me to independently verify and often preempt activities that SmartShift would take. The EMHASS author anticipates a 5-10% performance increase on rules based automations.

My setup is documented here: https://community.home-assistant.io/t/running-devices-when-energy-is-cheaper-and-greener/380011?u=markpurcell

I have documented my simple rules based system on Amber pricing and my more complex EMHASS configuration.

[herbi3]

thanks @purcell-lab - again, this is excellent! - The inverter won't reset as such, however if you run the command which changes the site limit, you'll hear the inverter 'tick' a few times, during that time it takes around 30s to start responding to modbus read/write requests. its something minimal when you're only reading data. I don't know what impact this has if the setting is changing very frequently.

EMHASS looks interesting, the python side seems depreciated now. which EMHASS looks great to use, I worry that if I use the pure python side, in the future it might be cumbersome to maintain or update. My homeassistant is running on a linux virtual machine using snap (dirty, but it works for my simple display)

Im wondering if there is something that has a web gui and runs as its own service where it has its own API with simple outputs (i.e charge battery now, discharge etc.)

[tux43]

I've now got around to create a blog showing how I created this #123 (comment)

https://www.smartmotion.life/2023/09/12/home-assistant-and-amber-electric-your-pathway-to-smarter-energy-management/