Add docs for easyEnergy integration (#25871)

source/_integrations/easyenergy.markdown

@@ -0,0 +1,54 @@
+---
+title: easyEnergy
+description: Instructions on how to integrate easyEnergy within Home Assistant.
+ha_category:
+  - Energy
+  - Sensor
+ha_release: 2023.3
+ha_iot_class: Cloud Polling
+ha_config_flow: true
+ha_codeowners:
+  - '@klaasnicolaas'
+ha_domain: easyenergy
+ha_platforms:
+  - sensor
+ha_quality_scale: platinum
+ha_integration_type: integration
+---
+
+The easyEnergy integration integrates the [easyEnergy](https://www.easyenergy.com) API platform with Home Assistant.
+
+The integration makes it possible to retrieve the dynamic energy/gas prices
+from easyEnergy in order to gain insight into the price trend of the day and
+to adjust your consumption accordingly.
+
+Companies that use the data from easyEnergy:
+
+- [NieuweStroom](https://nieuwestroom.nl)
+
+{% include integrations/config_flow.md %}
+
+## Sensors
+
+The easyEnergy integration creates a number of sensor entities for both gas
+and electricity prices.
+
+### Energy market prices
+
+In terms of electricity you get two separate services, easyEnergy uses separate
+prices for electricity that you use (buy) or return (sell). Every day around
+**14:00 UTC time**, the new prices are published for the following day.
+
+- The `current` and `next hour` electricity market price
+- Average electricity price of the day
+- Lowest energy price
+- Highest energy price
+- Time of day when the price is highest
+- Time of day when the price is at its lowest
+- Percentage of the current price compared to the maximum price
+
+### Gas market price
+
+For the dynamic gas prices, only entities are created that display the
+`current` and `next hour` price because the price is always fixed for
+24 hours; new prices are published every morning at **05:00 UTC time**.