Updated Sensor YAML for 2023/24: Adding National Grid’s DFS Dates to Home Assistant

National Grid have brought back the DFS scheme for the winter of 2023-24 and have made some changes to both how the scheme works and the data that is exposed via the API. Most significantly in terms of data, there is now a single combined dataset instead of one for the Live and Test events.

Home Assistant Sensor YAML

I strongly suggest using a package to keep the sensor yaml together rather than cluttering up your configuration file. The code below should be placed in file called national_grid_dfs–202324.yaml located in the directory /homeassistant/packages/National Grid DFS 2023-24/. You can of course pull the relevant code out of the below example and directly insert it in your configuration file.

This following package will create two sensors, one for the start date and time, and one for end date and time for the latest event. This loops through the data checking for the latest event, and then keeps looking to find the start time of the first session, and the end time of the last session in that event. This example is set for Octopus Energy, see the original post Adding National Grid’s DFS Dates to Home Assistant for information on how to change this to another supplier.

national_grid_dfs_202324:
## National Grid Demand Flexibility Service
    sensor:

        # Test Events - Octopus Accepted
        
        # Start Time and Date
      - platform: rest
        resource: "https://api.nationalgrideso.com/api/3/action/datastore_search_sql?sql=SELECT%20COUNT(*)%20OVER%20()%20AS%20_count,%20*%20FROM%20%22ed7019b0-32b7-425c-a2fb-5ba9e32733fb%22%20WHERE%20%22Status%22%20=%20'Accepted'%20AND%20%22Registered%20DFS%20Participant%22%20=%20'OCTOPUS%20ENERGY%20LIMITED'%20ORDER%20BY%20%22_id%22%20ASC%20LIMIT%20100"
        scan_interval: 900
        name: National Grid ESO Latest DFS Event Start 23-24
        unique_id: 2324_national_grid_eso_latest_event_dfs_start
        value_template: >-
            {% set d = value_json['result']['records'][0]['Delivery Date'] %}
            {% if '/' in d %}
                        {% set ns=namespace(start_time = strptime(d+' '+value_json['result']['records'][0]['From'],'%d/%m/%Y %H:%M')) %}
                        {% for record in value_json['result']['records'] %}
                          {% if record['Delivery Date'] == d -%}
                            {% if strptime(d+' '+record['From'],'%d/%m/%Y %H:%M') <= ns.start_time -%}
                              {% set ns.start_time = strptime(d+' '+record['From'],'%d/%m/%Y %H:%M') %}
                            {%- endif %}
                          {%- endif %}
                        {% endfor %}
            {% else %}
                        {% set ns=namespace(start_time = strptime(d+' '+value_json['result']['records'][0]['From'],'%Y-%m-%d %H:%M')) %}
                        {% for record in value_json['result']['records'] %}
                          {% if record['Delivery Date'] == d -%}
                            {% if strptime(d+' '+record['From'],'%Y-%m-%d %H:%M') <= ns.start_time -%}
                              {% set ns.start_time = strptime(d+' '+record['From'],'%Y-%m-%d %H:%M') %}
                            {%- endif %}
                          {%- endif %}
                        {% endfor %}
            {% endif %}         
            {{ns.start_time}}

        # End Time and Date
      - platform: rest
        resource: "https://api.nationalgrideso.com/api/3/action/datastore_search_sql?sql=SELECT%20COUNT(*)%20OVER%20()%20AS%20_count,%20*%20FROM%20%22ed7019b0-32b7-425c-a2fb-5ba9e32733fb%22%20WHERE%20%22Status%22%20=%20'Accepted'%20AND%20%22Registered%20DFS%20Participant%22%20=%20'OCTOPUS%20ENERGY%20LIMITED'%20ORDER%20BY%20%22_id%22%20ASC%20LIMIT%20100"
        scan_interval: 900
        name: National Grid ESO Latest DFS Event End 23-24
        unique_id: 2324_national_grid_eso_latest_event_dfs_end
        value_template: >-
            {% set d = value_json['result']['records'][0]['Delivery Date'] %}
            {% if '/' in d %}
                        {% set ns=namespace(end_time = strptime(d+' '+value_json['result']['records'][0]['To'],'%d/%m/%Y %H:%M')) %}
                        {% for record in value_json['result']['records'] %}
                          {% if record['Delivery Date'] == d -%}
                            {% if strptime(d+' '+record['To'],'%d/%m/%Y %H:%M') >= ns.end_time -%}
                              {% set ns.end_time = strptime(d+' '+record['To'],'%d/%m/%Y %H:%M') %}
                            {%- endif %}
                          {%- endif %}
                        {% endfor %}
            {% else %}
                        {% set ns=namespace(end_time = strptime(d+' '+value_json['result']['records'][0]['To'],'%Y-%m-%d %H:%M')) %}
                        {% for record in value_json['result']['records'] %}
                          {% if record['Delivery Date'] == d -%}
                            {% if strptime(d+' '+record['To'],'%Y-%m-%d %H:%M') >= ns.end_time -%}
                              {% set ns.end_time = strptime(d+' '+record['To'],'%Y-%m-%d %H:%M') %}
                            {%- endif %}
                          {%- endif %}
                        {% endfor %}
            {% endif %}         
            {{ns.end_time}}

Using the Sensors

Now that you’ve got the data, its possible to create automations in Home Assistant to turn off any unnecessary devices at the start time of the event, and turn them back on at the end. To do this, I created 2 date-time helpers which trigger such an automation. To update the date-time helper you need to create an automation that runs on a regular basis, or is triggered by the refreshing of the sensors. You can use similar to the below in the action section of an automation. Repeat this for each of the helpers and their corresponding sensors.

      - service: input_datetime.set_datetime
        data:
          datetime: >-
            {{
            strptime(states('sensor.2324_national_grid_eso_latest_event_dfs_start'),
            '%Y-%m-%d %H:%M:%S') }}
        target:
          entity_id: input_datetime.dfs_event_start