Price calc

Home assistant custom component for calculating price of running a electric appliance with non-linear energy usage.

For getting the electricity prices the awesome Energi Data Service custom component from @MTrab is required.

Simulates the price using a rolling window: ![price_calc_principle]

Blue: electricity price
Black: energy usage
Red: calculated price for running appliance

THIS IS ONLY TESTED USING A SHELLY PLUG S

Creates a single sensor with current price and following attributes:

Entities with home charger

Attribute	Description
current_time	Datetime matching the price_now sensor.
next_lowest	Datetime of the lowest calculated price with available energy prices that has not yet parsed.
next_lowest price	Lowest calculated price with available energy prices that has not yet parsed.
diff_now_and_next_lowest	Difference in calculated price now compared to the next cheapest calculated price.
delay_hours	Delay in whole hours to cheapest start hourly from now. Be aware that this is not necessarily the absolute cheapest time.
delay_hours_price	Calculated price when delaying for delay_hours.
diff_now_and_delay	Calculated price difference when starting appliance now versus delaying for delay_hours.
todays_highest	The highest calculated price with available energy prices.
today_highest_time	Datetime of the highest calculated price with available energy prices.
todays_lowest	The lowest calculated price with available energy prices.
today_lowest_time	Datetime of the lowest calculated price with available energy prices.
price_data	All calculated prices and datetimes with available data. This is optional to add during setup. Be aware that this attribute can contain a lot of data!

Data

History

For best results a consistent energy usage of electric appliance is needed. I have tested it using af Shelly Plug S. When using default Shelly integration data was updated with inconsistency, ranging from update interval from 45-75 seconds.
When adding a REST sensor like this:

rest:
  resource: http://192.168.1.83/meter/0
  scan_interval: 1
  sensor:
    - name: "shelly_rest_energy"
      unique_id: "shelly_rest_energy"
      unit_of_measurement: "kWh"
      value_template: "{{ value_json.total / 60000 }}"

Update interval variance was less than 1 second. Make sure to delete this sensor after creating the price calc sensor to reduce network traffic.

File

If you already have downloaded a config file or added to the custom_components/price_calc/data you can select this file during setup. Be aware that you need to restart Home Assistant if file is added while Home Assistant is running.

URL

You can share and download config files from https://github.com/fars-fede-fire/price_calc_data

1. Find the file you want to use in the repo and open it.
2. Click 'Raw' in the upper right corner.
3. Copy the URL and insert during setup when prompted.