Home Assistant Czech Energy Spot Prices

Home Assistant integration that provides current Czech electricity spot prices based on OTE.

Features

• Provides real-time Czech electricity spot and gas prices from OTE.
• Supports multiple currencies (EUR, CZK) and energy units (kWh, MWh).
• Configurable templates for buy/sell prices, including VAT and distribution fees.
• Includes sensors for monitoring current, cheapest, and most expensive electricity prices.
• Compatible with Home Assistant automations for energy optimization.

Important note

OTE (Czech market operator) uses hourly prices indexed from 1, where:

• 1 (first hour of the day) corresponds to 00:00 - 01:00.
• It does not mean 01:00 - 02:00, as one might expect.

Keep this in mind when comparing prices reported by this integration with other sources (e.g., OTE, your electricity provider/distributor).

Screenshot

See Displaying a chart for details.

Buy and sell prices

The integration shows just spot prices by default. If you want to also use actual prices for buying and selling (so including distribution fees, VAT, etc), you need to configure it. Use the "Configure" button in integration details and set templates for buying/selling.

Variables:

• hour variable to see what hour is currently being computed.
• value is base spot price for given hour.

Example templates

Electricity cost when buying

{% set tax_kWh = 28.30 / 1000.0 %}
{% set system_services_kWh = 212.82 / 1000.0 %}
{% set oze_kWh = 495 / 1000.0 %}
{% set low_distrib_kWh = 450.43 / 1000.0 %}
{% set high_distrib_kWh = 644.30 / 1000.0 %}
{% set operator_cost_kWh = 350.0 / 1000.0 %}
{% set vat_percent = 21 %}

{% set distrib_kWh = low_distrib_kWh %}
{% if as_local(hour).hour in [9, 12, 16, 20] %}
  {% set distrib_kWh = high_distrib_kWh %}
{% endif %}

{{ (value + distrib_kWh + tax_kWh + oze_kWh + system_services_kWh + operator_cost_kWh) * ( 100.0 + vat_percent ) / 100.0 }}

Electricity cost when selling

{% set operator_cost_kWh = 0.25 %}
{{ value - operator_cost_kWh }}

Installation

You can install the integration using HACS (preferred) or manually.

HACS (preferred)

1. Open HACS in your Home Assistant instance.
2. Search for "Czech Energy Spot Prices" and install it.
3. Restart Home Assistant.

Manual

1. Download the custom_components/cz_energy_spot_prices directory.
2. Copy it into the custom_components folder in your Home Assistant configuration directory.
3. Restart Home Assistant.

Add and configure the integration

1. Go to Settings -> Devices & Services -> Add integration.
2. Search for "Czech Energy Spot Prices" and select it.
3. Configure the currency and energy unit.
4. (Optional) Use the "Configure" button to set templates for buy/sell prices (see above).

Sensors

The integration provides several sensors to monitor electricity/gas prices and related data. Below is a list of available sensors and their attributes:

Sensor	value	attributes
Current Spot Electricity Price	electricity price for current hour	dictionary with timestamps as keys and spot price for given hour as values
Spot Cheapest Electricity Today	price of the cheapest electricity today	At Hour
Spot Most Expensive Electricity Today	price of the most expensive electricity today	At Hour
Spot Cheapest Electricity Tomorrow	price of the cheapest electricity tomorrow	At Hour
Spot Most Expensive Electricity Tomorrow	price of the most expensive electricity tomorrow	At Hour
Current Spot Electricity Hour Order	order of current hour when we sort hours by its price (1=cheapest, 24=most expensive)	dictionary with timestamps as keys and order, price as values
Tomorrow Spot Electricity Hour Order	no value	dictionary with timestamps as keys and order, price as values
Spot Electricity Has Tomorrow Data	On when data for tomorrow are loaded, Off otherwise
Spot Electricity Is Cheapest	On when current hour has the cheapest price, Off otherwise	Start Start hour End End hour Min Max Mean
Spot Electricity Is Cheapest X Hours Block	On when current hour is in a block of cheapest consecutive hours, Off otherwise	Start Start hour End End hour Min Max Mean

If you configure templates for buy and sell prices, there will also be similar sensors for buy/sell prices.

Common attributes

At

timestamp when the cheapest hour starts

Hour

hour with the cheapest electricity (2 means that cheapest electricity is from 2:00 till 3:00 in timezone you've configured in Home Assistant)

Start

timestamp when consecutive block of cheapest hours starts, only available when the block is in the future

Start hour

hour when consecutive block of cheapest hours starts, only available when the block is in the future

End

timestamp when consecutive block of cheapest hours ends, only available when the block is in the future

End hour

hour when consecutive block of cheapest hours ends, only available when the block is in the future

Min

minimal price in the block, only available when the block is in the future

Max

maximal price in the block, only available when the block is in the future

Mean

average (mean) price in the block, only available when the block is in the future

Displaying a chart

If you want to display a chart with current day (or two days if it's after noon), you can install apexcharts-card card for Home Assistant and then use following config for it:

type: custom:apexcharts-card
header:
  show: true
  show_states: true
  colorize_states: true
graph_span: 2d
span:
  start: day
now:
  show: true
  label: Now
series:
  - entity: sensor.current_spot_electricity_price
    float_precision: 2
    type: column # or "line" if you prefer
    show:
      in_header: raw
    data_generator: |
      return Object.entries(entity.attributes).map(([date, value], index) => {
        return [new Date(date).getTime() + (30 * 60 * 1000), value];
      });

Find cheapest hours in selected interval

This is useful for example if you want to turn on your water heater in the afternoon and then again during the night.

How It Works

• Define intervals as tuples (start_hour, end_hour) (end hour is excluded).
• The sensor will return True if the current hour is the cheapest in any of the defined intervals.
• Alternatively, replace the last line with {{ min.cheapest_hours }} to display the cheapest hours.

Example Template Sensor

{# Define your intervals here as tuples (hour starting the interval, hour ending the interval (excluded)) #}
{% set intervals = [
  (0, 8),
  (8, 16),
  (16, 24),
] %}

{# We need to use namespace so we can write into it in inner cycle #}
{% set min = namespace(price=None, dt=None, cheapest_hours=[]) %}
{% set cheapest_hours = [] %}


{% for interval in intervals %}
  {# Reset min price from previous runs #}
  {% set min.price = None %}

  {# Go through all the hours in the interval (end excluded) and find the hour with lowest price #}
  {% for i in range(interval[0], interval[1]) %}
     {# Get datetime of current hour in current interval #}
     {% set hour_dt = now().replace(hour=i, minute=0, second=0, microsecond=0) %}

     {# Get value for that hour #}
     {% set value = states.sensor.current_spot_electricity_hour_order.attributes.get(hour_dt.isoformat()) %}

     {# Skip if not found #}
     {% if value is not defined %}
       {% break %}
     {% endif %}

     {# value is tuple (order, price), we'll use the price #}
     {% set price = value[1] %}

     {# Min price is not set or is higher than price of current hour => store the min price and hour #}
     {% if min.price is none or price < min.price %}
        {% set min.price = price %}
        {% set min.dt = hour_dt %}
     {% endif %}
  {% endfor %}

  {# Store cheapest hour in current interval #}
  {% set min.cheapest_hours = min.cheapest_hours + [min.dt.hour] %}
{% endfor %}

{# use this to get the cheapest hours #}
{# {{ min.cheapest_hours }} #}

{# return True if current hour is in the cheapest hour of any interval #}
{{ now().hour in min.cheapest_hours }}

Example automation for X cheapest hours

This automation turns on a device (e.g., a heater) during the cheapest X hours of the day. Replace X with the desired number of hours and specify the entity to control.

alias: Turn on for cheapest X hours
trigger:
  - platform: state
    entity_id:
      - sensor.current_spot_electricity_hour_order
condition: []
action:
  - if:
      - condition: numeric_state
        entity_id: sensor.current_spot_electricity_hour_order
        below: X # Replace with amount of hours you want to have it on
    then:
      - type: turn_on
        entity_id: # Add entity you want to turn on
    else:
      - type: turn_off
        entity_id: # Turn off the entity when cheapest interval ends
    enabled: true
mode: single

License

This integration is under Apache 2.0 License, the same license as Home Assistant itself.