Solar Power Zero Grid Export - Home Assistant Automation

README.md

Solar Power Zero Frid Export - Home Assistant Automation

Prerequisites

• grid power / smart meter, connected to Home Assistant (e.g. Bayha Electronics Tasmota IR)
• locally reachable inverter with variable output control, connected to Home Assistant (e.g. APSystems EZ1
• SunLit Solar Custom Integration installed in Home Assistant (e.g. via HACS)

Description

• run on every change to the current total power (grid) consumption or production
• alternatively: trigger every 9s
• only if the delta is <> 10W
• calculate interver target power to achieve 0W grid consumption
• use min power setting when the battery minimum level is reached

Global Variables

Variable	Description
battery_level_entity_id	Entity for the current battery level, i.e. "Average Battery Level" from the SunLit REST HACS integration
batter_level_min_entity_id	input_number helper id to configure minimum battery level to stop the power output
grid_current_power	Current total grid consumption. Negative means export, positive mean consumption
inverter_control_entity_id	Inverter entity to set desired power output
inverter_rated_power	Inverter rated power (maximum output you want to allow), e.g. 800W
inverter_min_power_entity_id	input_number helper id to configure the inverter's min power setting. E.g. 30W for APSystems EZ1-M. Used once min battery level is reached.
inverter_min_power	Value from above entity
step	Step size in which to increase / decrease power output

Action Variables

Variable	Description
battery_level_min	Minimum battery level configured. Stops power output once reached.
battery_level_current	Current Battery level from battery_level_entity_id
inverter_current_power	Currently set inverter power output from inverter_control_entity_id
inverter_current_power_stepped	inverter_current_power normalized to the next step, e.g. 34 => 40
grid_current_power_stepped	grid_current_power normalized to the next step, e.g. 123 => 130, -44 => -40
target_power	Calculated desired output power to set on the inverter
target_power_clamped	target_power contraint to min and max values of the inverter
log_message	some debug output
inverter_control_number_set_value_action	internal purposes only

Helpers

Helpers used in this automation.
Either create them in your Home Assistant instance, or use hard-coded values in their place.

Name	Description
input_number.solar_battery_level_min	Minimum battery level at which the automation stops
input_number.solar_inverter_rated_power	Rated Power output of your inverter. Used to clamp the calculated target power output
input_number.solar_inverter_output_min	Minmum target output power. Used once minimum battery level is reached. The automation can not turn off your inverter!
input_select.solar_power_feed_strategy	List of available strategies. Automation checks for value zero grid export

automation.yaml

alias: "solar_power_feed_zero_export"
triggers:
  # Trigger when power consumption changes
  - trigger: "state"
    entity_id: "sensor.energy_power_current"
    # set `to` to `null`, otherwise the automation will trigger
    # for both `from` and `to` states, as well as attribute changes
    to: null
  # Trigger every 9 seconds
  # - trigger: "time_pattern"
  #   seconds: "/9"
variables:
  # Battery
  battery_level_entity_id: "sensor.home_solar_system_average_battery_level"
  battery_level_min_entity_id: "input_number.solar_battery_level_min"
  # Current grid power (positive = importing, negative = exporting)
  grid_current_power: >
    {{ states("sensor.energy_power_current") | int(0) }}
  # Inverter number entity controlling output power
  inverter_control_entity_id: "number.solar_max_output"
  # Inverter max rated output power
  inverter_rated_power: >
    {{ states("input_number.solar_inverter_rated_power") }}
  # Inverter min output power setting
  inverter_min_power_entity_id: input_number.solar_inverter_output_min
  inverter_min_power: >
    {{ states(inverter_min_power_entity_id) }}
  # Step size for power calculations
  step: 10

conditions:
  # Don't run if grid consumption/production is within acceptable parameters
  - condition: "template"
    value_template: >
      {{ not (-(step) < grid_current_power < step) }}
  # Don't run if strategy isn't active
  - condition: "state"
    entity_id: "input_select.solar_power_feed_strategy"
    state: "zero grid export"
  # Don't run if the grid connection is interrupted
  - condition: "state"
    entity_id: "switch.0xa4c13833f21e39cf"
    state: "on"
actions:
  - variables:
      # Minimum battery level
      battery_level_min: >
        {{ states(battery_level_min_entity_id) | int(0) }}
      battery_level_current: >
        {{ (states(battery_level_entity_id) | int(0)) }}
      # Current output power set on the inverter
      inverter_current_power: >
        {{ states(inverter_control_entity_id) | round(0) }}
      # Normalize to steps
      inverter_current_power_stepped: >
        {{ (inverter_current_power // step) * step }}
      # Calculated target power setting (in steps of `step`)
      grid_current_power_stepped: >
        {{ ((grid_current_power // step) + 1) * step }}
      # New target output power value for inverter
      target_power: >
        {{ (inverter_current_power_stepped + grid_current_power_stepped) }}
      # New Target output power, clamped for min and max values
      target_power_clamped: >
        {{ [([target_power, inverter_rated_power] | min), inverter_min_power] | max }}
      # Debug logging message
      log_message: >
        {{
          "Grid:" ~ grid_current_power ~ "W | " ~
          "Grid (stepped):" ~ grid_current_power_stepped ~ "W | " ~
          "Inverter current:" ~ inverter_current_power ~ "W | " ~
          "Inverter current (stepped):" ~ inverter_current_power_stepped ~ "W | " ~
          "Inverter rated:" ~ inverter_rated_power ~ "W | " ~
          "Target:" ~ target_power ~ "W | " ~
          "Target (clamped):" ~ target_power_clamped ~ "W"
        }}
      # Switch action based on inverter_controller_entity type
      inverter_control_number_set_value_action: >
        {% if inverter_control_entity_id.startswith("input_number.") %}
          input_number.set_value
        {% else %}
          number.set_value
        {% endif %}

  - action: "system_log.write"
    data:
      level: "info"
      message: "Zero Power Feed: {{ now().strftime('%H:%M:%S') }} | {{ log_message }}"

  - if:
      # Don't set calculated target power when battery is low
      - condition: "template"
        value_template: >
          {{ battery_level_current >= battery_level_min }}
    then:
      - action: "{{ inverter_control_number_set_value_action }}"
        target:
          entity_id: "{{ inverter_control_entity_id }}"
        data:
          value: "{{ target_power_clamped }}"
    else:
      # Instead, set inverter min power when battery is low
      - action: "{{ inverter_control_number_set_value_action }}"

        target:
          entity_id: "{{ inverter_control_entity_id }}"
        data:
          value: "{{ inverter_min_power }}"