EV Charging cost blueprint project

# EV Charging Cost Calculator Blueprint
# -------------------------------------
# Project Description:
# This blueprint is designed to calculate the **cheapest hour** to charge your electric vehicle (EV)
# based on electricity prices fetched from the Nordpool integration.
# It also provides calculations for:
#   - The total cost of charging at the current hour
#   - The total cost of charging at the cheapest hour
#   - Potential savings if you wait for the cheapest hour
#   - Energy needed to fully charge the EV (kWh)
#   - Number of hours required to fully charge the EV
#
# The results are stored in helper entities (input_text), which can then be displayed
# on a Home Assistant dashboard (Lovelace) for easy monitoring and decision-making.
#
# Purpose:
# This blueprint allows EV owners to optimize their charging schedules to save money
# by charging during the cheapest electricity hours.
# It considers additional costs like VAT and extra fees per kWh.
#
# Key Features:
# - Automatically calculates the **cheapest charging window**.
# - Displays **savings** when comparing current charging costs to the cheapest hour.
# - Updates results dynamically when electricity prices or battery level changes.
# - Allows integration into Lovelace dashboards for real-time cost tracking.
#
# -------------------------------------
# Installation Instructions:
# 1. Copy this blueprint YAML file and place it in the 'blueprints/automation/[YourFolderName]' directory in Home Assistant.
# 2. Reload the automations or restart Home Assistant.
# 3. Navigate to the Automations section in Home Assistant.
# 4. Create a new automation, select 'Blueprints', and choose 'EV Charging Cost Calculator'.
# 5. Configure the required inputs:
#    - Nordpool Price Entity (sensor)
#    - Battery Percentage Entity (sensor)
#    - Battery Capacity (kW)
#    - Charger Capacity (kW)
#    - VAT Percentage (%)
#    - Extra Cost per kWh (kr)
#    - Default Cost per kWh (kr)
#    - Helper Entities (input_text) for:
#        - Cheapest Start Hour
#        - Cheapest Cost
#        - Current Cost
#        - Savings
#        - Energy Needed
#        - Hours Needed
# 6. Save the automation and it will begin calculating based on the Nordpool prices and your EV configuration.
# 7. Add the helper entities to your Lovelace dashboard for monitoring.
#
# Disclaimer:
# -------------------------------------------------------------
# This blueprint is provided "as is" without any guarantees or warranties.
# I take no responsibility for any issues, damages, or inaccuracies that
# may occur as a result of using this blueprint.
#
# This was my first blueprint and was created as a fun project.
# There may be calculation errors, bugs, or logical mistakes.
#
# **Use it at your own risk.** You are responsible for verifying
# all results and ensuring it meets your needs. This blueprint
# is not professionally tested, and I cannot provide support.
#
# If something goes wrong, or the numbers seem incorrect,
# double-check all calculations and configurations.
# -------------------------------------------------------------



blueprint:
  name: EV Charging Cost Calculator
  description: Calculate the cheapest hour and cost to charge your EV based on Nordpool prices.
  domain: automation
  input:
    nordpool_entity:
      name: Nordpool Price Entity
      selector:
        entity:
          domain: sensor
    battery_percentage_entity:
      name: Battery Percentage Entity
      selector:
        entity:
          domain: sensor
    battery_capacity:
      name: Battery Capacity (kW)
      default: 40
      selector:
        number:
          min: 1
          max: 200
    charger_capacity:
      name: Charger Capacity (kW)
      default: 3.6
      selector:
        number:
          min: 1
          max: 22
    vat_percentage:
      name: VAT Percentage
      default: 25
      selector:
        number:
          min: 0
          max: 100
    extra_cost_per_kwh:
      name: Extra Cost per kWh (kr)
      default: 0.05
      selector:
        number:
          min: 0
          max: 5
    default_cost_per_kwh:
      name: Default Cost per kWh (kr)
      default: 0.5
      selector:
        number:
          min: 0
          max: 5
    cheapest_start_hour_entity:
      name: Cheapest Start Hour Helper
      selector:
        entity:
          domain: input_text
    cheapest_cost_entity:
      name: Cheapest Cost Helper
      selector:
        entity:
          domain: input_text
    current_cost_entity:
      name: Current Cost Helper
      selector:
        entity:
          domain: input_text
    savings_entity:
      name: Savings Helper
      selector:
        entity:
          domain: input_text
    energy_needed_entity:
      name: Energy Needed Helper
      selector:
        entity:
          domain: input_text
    hours_needed_entity:
      name: Hours Needed Helper
      selector:
        entity:
          domain: input_text

trigger:
  - platform: state
    entity_id: !input nordpool_entity
  - platform: state
    entity_id: !input battery_percentage_entity

variables:
  nordpool_entity: !input nordpool_entity
  battery_percentage_entity: !input battery_percentage_entity
  default_cost_per_kwh: !input default_cost_per_kwh
  today_prices: >
    {{ state_attr(nordpool_entity, 'today') | default([default_cost_per_kwh]) | list }}
  tomorrow_prices: >
    {{ state_attr(nordpool_entity, 'tomorrow') | default([default_cost_per_kwh]) | list }}
  combined_prices: >
    {{ today_prices + tomorrow_prices }}
  vat: !input vat_percentage
  extra_cost: !input extra_cost_per_kwh
  battery_capacity: !input battery_capacity
  charger_capacity: !input charger_capacity
  battery_percentage: >
    {{ states(battery_percentage_entity) | float(0) }}
  energy_needed_kwh: >
    {{ ((100 - battery_percentage) / 100) * battery_capacity }}
  hours_needed: >
    {{ (energy_needed_kwh / charger_capacity) | round(0, 'ceil') }}
  current_hour: >
    {{ now().hour }}

  this_cheapest_price: >
    {% set ns = namespace(min_cost=None, start_hour=None) %}
    {% for i in range(current_hour, combined_prices | length - hours_needed + 1) %}
      {% set hourly_cost = combined_prices[i:i+hours_needed] | sum %}
      {% if ns.min_cost is none or hourly_cost < ns.min_cost %}
        {% set ns.min_cost = hourly_cost %}
        {% set ns.start_hour = i %}
      {% endif %}
    {% endfor %}
    {% if ns.start_hour is not none %}
      {% if ns.start_hour < 24 %}
        {{ ns.start_hour }}
      {% else %}
        {{ (ns.start_hour - 24) | string.zfill(2) }} (Tomorrow)
      {% endif %}
    {% else %}N/A{% endif %}

  this_cheapest_cost: >
    {% set ns = namespace(min_cost=None) %}
    {% for i in range(current_hour, combined_prices | length - hours_needed + 1) %}
      {% set hourly_cost = combined_prices[i:i+hours_needed] | sum %}
      {% if ns.min_cost is none or hourly_cost < ns.min_cost %}
        {% set ns.min_cost = hourly_cost %}
      {% endif %}
    {% endfor %}
    {{ ((ns.min_cost + hours_needed * extra_cost) * (1 + vat / 100)) | round(2) if ns.min_cost is not none else 'N/A' }}

  this_current_cost: >
    {% set now_hour = current_hour %}
    {% if now_hour + hours_needed <= combined_prices | length %}
      {% set current_cost = combined_prices[now_hour:now_hour+hours_needed] | sum %}
      {{ ((current_cost + hours_needed * extra_cost) * (1 + vat / 100)) | round(2) }}
    {% else %}N/A{% endif %}

  this_saving: >
    {% set cheapest_cost = this_cheapest_cost | float(0) %}
    {% set current_cost = this_current_cost | float(0) %}
    {{ (current_cost - cheapest_cost) | round(2) if cheapest_cost != 'N/A' and current_cost != 'N/A' else 'N/A' }}

action:
  - service: input_text.set_value
    data:
      entity_id: !input energy_needed_entity
      value: >
        {{ energy_needed_kwh | round(2) }}

  - service: input_text.set_value
    data:
      entity_id: !input hours_needed_entity
      value: >
        {{ hours_needed }}

  - service: input_text.set_value
    data:
      entity_id: !input cheapest_start_hour_entity
      value: >
        {{ this_cheapest_price }}

  - service: input_text.set_value
    data:
      entity_id: !input cheapest_cost_entity
      value: >
        {{ this_cheapest_cost }}

  - service: input_text.set_value
    data:
      entity_id: !input current_cost_entity
      value: >
        {{ this_current_cost }}

  - service: input_text.set_value
    data:
      entity_id: !input savings_entity
      value: >
        {{ this_saving }}