Control my Hot Water element during peak power times.

hot_water_cylinder.yaml

# ###################################
# ##  Automations
# ###################################
automation:
  - alias: Turn off Hot Water Cylinder Mid-Week
    id: 1d494c80-41eb-42eb-8e22-60a3606c29d9
    trigger:
      - platform: time
        at: '00:01:00'    
      - platform: time
        at: '07:00:00'
      - platform: time
        at: '17:00:00'
    condition:
      condition: time
      weekday:
      - mon
      - tue
      - wed
      - thu
      - fri
    action:
      - service: switch.turn_off
        entity_id: switch.hot_water_cylinder_control

  - alias: Turn on Hot Water Cylinder Mid-Week
    id: c1d865ec-c6dd-4b2b-9a5f-5d6833977d3f
    trigger:
      - platform: time
        at: '05:45:00'    
      - platform: time
        at: '11:00:00'
      - platform: time
        at: '21:00:00'
    condition:
      condition: time
      weekday:
      - mon
      - tue
      - wed
      - thu
      - fri
    action:
      - service: switch.turn_on
        entity_id: switch.hot_water_cylinder_control

  - alias: 'HWC Heating On'
    id: 59a99b3d-6f69-48ae-99c0-37fe9e4311e1
    initial_state: true
    
    trigger:
      - platform: numeric_state
        entity_id: sensor.hwc_shelly_power
        above: 0.4
        for:
          seconds: 10
    condition:
      - condition: state
        entity_id: input_boolean.hwc_element
        state: 'off'
    action:
      - service: input_boolean.turn_on
        entity_id: input_boolean.hwc_element

  - alias: 'HWC Heating Off'
    id: cbb4e38a-5638-46e1-8d56-57034606672d
    initial_state: true
    
    trigger:
      - platform: numeric_state
        entity_id: sensor.hwc_shelly_power
        below: 0.4
        for:
          seconds: 10
    condition:
      - condition: state
        entity_id: input_boolean.hwc_element
        state: 'on'
    action:
        - service: input_boolean.turn_off
          entity_id: input_boolean.hwc_element

input_boolean:
  hwc_element:
    name: Status - Off | On
    initial: off
    icon: mdi:water-boiler      

binary_sensor:
  - platform: mqtt
    name: "HWC Shelly MQTT Status"
    state_topic: "shellies/shelly1pm-76AE0C/online"
    value_template: "{{ value }}"
    payload_on: "true"
    payload_off: "false"
    device_class: connectivity

sensor:
  - platform: template
    sensors:
      hwc_element_status:
        friendly_name: "HWC Element Status"
        value_template: "{% if states('sensor.hwc_shelly_power') | float > 0.4 %}Auto{% else %}Off{% endif %}"

# Reports 'on' time as a decimal #
  - platform: history_stats
    name: HWC Heating Today
    entity_id: sensor.hwc_element_status
    state: 'Auto'
    type: time
    start: '{{ now().replace(hour=0).replace(minute=0).replace(second=0) }}'
    end: '{{ now() }}'

# Converts above sensor from decimal to Hours and Minutes. Only used to UI #
  - platform: template
    sensors:
      hwc_heating_time_on:
        value_template: '{{ states.sensor.hwc_heating_today.attributes.value }}'
        friendly_name: 'HWC Hours Heating'

My complete package above for control of my hot water cylinder. A Shelly1 controls a solid state relay that can handle 25 amps (mounted on a heatsink!). Prevents the cylinder from heating during peak power rates which is 0700-1100 and 1700-2100 Mon-Fri.