Hi everyone, I hope you have a great day!
As a small Sunday project, I decided to display the European power grid frequency in HA. I don’t have any hardware to measure it at home, so I searched for a way to utilize free online services. And why not share my solutions with the rest of you :). Ideas and recommendations are very welcome, I’m also fairly new to HA.
Why
I am living in Germany and I saw a video about the power grid and how the frequency reflects the health of the grid. This made me curious and wanted to dive deeper into the topic. I also wanted to represent the data in my HA dashboard.
Providers
At the time of writing this post, I found three data providers.
- netzfrequenz.info
- Pros
- Simple
- High update rate
- Cons
- Data provided by a private project
- Pros
- gridradar.net
- Pros
- API
- Professional service
- Cons
- Low update rate (1m)
- Pros
- netzfrequenzmessung.de
- Pros
- Also provides phase-angle relative to 50Hz
- High update rate (up to 1s)
- Cons
- Limited queries per day
- No official API
- Pros
Solutions
Solution 1: netzfrequenz.info
BEST
My most recent and also preferred solution. The endpoint returns just the current frequency without any bells and whistles. An update frequency of 1-second is also nice to have. The project is run by a single person and the provider states that the data should not be used for any controlling tasks.
Update Nov. 2024: I have updated the sensor configuration based on an improvement provided by @haip 
Add the sensor config to your: /homeassistant/configuration.yaml
sensor:
- platform: rest
name: Netzfrequenz
resource: "https://www.netzfrequenz.info/json/act.json"
force_update: true
scan_interval: 3
value_template: >
{% set netzfrequenz = float(value_json) | round(2) %}
{% if netzfrequenz == 49 %}
{{ states('sensor.netzfrequenz') }}
{% else %}
{{ netzfrequenz }}
{% endif %}
icon: mdi:sine-wave
unit_of_measurement: Hz
state_class: measurement
Solution 2: gridradar.net
Good
Gridradar sells its grid data for monitoring and analysis and provides an API. A better and more solid solution. A gridradar.net user account is required for this sensor. It works well so far, is simple, and provides API documentation. The update rate seems to be limited to around one query every ~60 seconds. The API returns a list of data points since the last query with the provided key, my implementation just picks the last one from the list and discards the rest.
Note: You have to set your API token in your secrets.yaml.
Example: gridradar_net_token: Bearer your-token
- platform: rest
# Grid Frequency (gridradar.net)
name: gridradar_net_frequency_ucte
resource: "https://api.gridradar.net/query"
headers:
Authorization: !secret gridradar_net_token # bearer token
Content-Type: application/json
payload: '{"metric":"frequency-ucte-median-1s", "aggr":"1m"}'
force_update: true
scan_interval: 60 # the request interval for the free plan is limited, updating every 1 minute has proven to be the best
value_template: "{{ float(value_json[0].datapoints[-1:][0][0]) | round(2) }}"
unit_of_measurement: "Hz"
state_class: "measurement"
Solution 3: netzfrequenzmessung.de
Limited
Probably the last solution you should use. The biggest downside of this provider is the statement that the display of the network frequency is limited per day. From my understanding, they say “display” because pulling the XML is not officially documented. Another limitation is the XML content type used by the website. It is defined as plain text, which makes HA not being able to convert it from XML to JSON automatically. If there is an option to force XML as the resource content type, please let me know :). Right now I’m going through a public XML to JSON converter. Ugly & fragile.
- platform: rest
# Powergrid Frequency (netzfrequenzmessung.de)
# Limitiations:
# - Requires "xml-to-json" proxy
# - Limited requests per day: https://www.netzfrequenzmessung.de/konzept.htm
name: netzfrequenzmessung_de_dataprovider
resource: "https://api.factmaven.com/xml-to-json/?xml=https://netzfrequenzmessung.de:9080/frequenz02.xml" # proxy is required because endpoint returns plain text content type
force_update: true
scan_interval: 10
json_attributes_path: "$.r"
state_class: "measurement"
value_template: "OK"
json_attributes:
- f2
- p
- platform: template
sensors:
netzfrequenzmessung_de_frequency_ucte:
unit_of_measurement: "Hz"
value_template: "{{ float(state_attr('sensor.netzfrequenzmessung_de_dataprovider', 'f2')) | round(2) }}"
netzfrequenzmessung_de_phase_angle_ucte:
unit_of_measurement: "°"
value_template: "{{ float(state_attr('sensor.netzfrequenzmessung_de_dataprovider', 'p')) }}"
Extra: I also found an iframe on netzfrequenz.info that can be implemented as a panel webpage. The labels are in German though. https://www.netzfrequenz.info/charts/gauge_full.php
Wish you all the best, Tilman 
