Hello,
I live in Germany which has high energy prices currently. I decided to go for a flexible tariff from tibber. Some days you see price differences of 30€ents during the day.
This is a price curve for a day like today.
I build a set of automations to ensure the house battery is charged from the grid during cheap hours (below the white band) and discharged during peak hours (above the white band).
This is done only if the there is a high delta in price during the day. This threshold is introduced to ensure we dont loose the benefit bc f the losses between charging and discharging the battery. The required delta can be configured (here 0.08€).
The battery is charged if the current price is in the lower 5% of the spread and discharged only when the current price is above 50% of the current spread.
In winter, when solar yield is low and we see such a price difference, I can save some 2-3€ during the day. It adds up … and it is fun. Why paying high energy prices when you can build some fancy automations ,-).
I have tibber integration which gives me current price and forecast.
- platform: template
sensors:
tibber_price_delta:
friendly_name: "Tibber Price Delta"
value_template: >
{% set max_price = ([states.sensor.tibber_prices.attributes.today | map(attribute='total') | list, states.sensor.tibber_prices.attributes.tomorrow | map(attribute='total') | list] | sum(start=[]) | max | float) %}
{% set min_price = ([states.sensor.tibber_prices.attributes.today | map(attribute='total') | list, states.sensor.tibber_prices.attributes.tomorrow | map(attribute='total') | list] | sum(start=[]) | min | float) %}
{% set price_delta = (max_price - min_price) | float %}
{{ price_delta }}
unit_of_measurement: €
- platform: template
sensors:
tibber_price_charge_target:
friendly_name: "Tibber Price Charge Target"
value_template: >
{% set max_price = ([states.sensor.tibber_prices.attributes.today | map(attribute='total') | list, states.sensor.tibber_prices.attributes.tomorrow | map(attribute='total') | list] | sum(start=[]) | max | float) %}
{% set min_price = ([states.sensor.tibber_prices.attributes.today | map(attribute='total') | list, states.sensor.tibber_prices.attributes.tomorrow | map(attribute='total') | list] | sum(start=[]) | min | float) %}
{% set now_price = states('sensor.tibber_prices') | float %}
{% set price_weight = ((1 - (now_price - min_price) / (max_price - min_price)) * 100 ) | int %}
{% set price_target= (min_price + (states('input_number.evcc_battery_charge_percentile') | float / 100) * (max_price - min_price)) | float %}
{{ ((price_target * 1000) + 0.999) // 1 / 1000 }}
unit_of_measurement: €
- platform: template
sensors:
tibber_price_discharge_target:
friendly_name: "Tibber Price Discharge Target"
value_template: >
{% set max_price = ([states.sensor.tibber_prices.attributes.today | map(attribute='total') | list, states.sensor.tibber_prices.attributes.tomorrow | map(attribute='total') | list] | sum(start=[]) | max | float) %}
{% set min_price = ([states.sensor.tibber_prices.attributes.today | map(attribute='total') | list, states.sensor.tibber_prices.attributes.tomorrow | map(attribute='total') | list] | sum(start=[]) | min | float) %}
{% set now_price = states('sensor.tibber_prices') | float %}
{% set price_weight = ((1 - (now_price - min_price) / (max_price - min_price)) * 100 ) | int %}
{% set price_target= (min_price + (states('input_number.evcc_battery_discharge_percentile') | float / 100) * (max_price - min_price)) | float %}
{{ ((price_target * 1000) + 0.999) // 1 / 1000 }}
unit_of_measurement: €
I steer my battery charging and discharging or blocking the discharging via EVCC.
In EVCC I introduced a dummy loadpoint in evcc.yaml.
chargers:
- name: dummy
status: C
type: template
template: demo-charger
enabled: true
loadpoints:
- title: Dummy
charger: dummy
mode: off
With this i can easily set the price points where the house battery should be charged. If the dummy loadpoint is charging, EVCC prevents the battery from being discharged. Be sure you configure EVCC properly. Be sure you have experimental mode set to on in EVCC so you can find the required options.
- alias: Sync EVCC Battery Charge Limit with Tibber Price Target
description: Set the EVCC battery grid charge limit to the value of the Tibber price target whenever it changes.
trigger:
- trigger: state
entity_id: sensor.tibber_price_charge_target
- trigger: homeassistant
event: start
condition:
- condition: template
value_template: >
{{ (states('sensor.tibber_price_delta') | float) > ((states('input_number.evcc_battery_charge_delta')) | float) }}
action:
- delay: "00:00:30"
- action: number.set_value
target:
entity_id: number.evcc_battery_grid_charge_limit
data:
value: "{{ states('sensor.tibber_price_charge_target') | float }}"
mode: single
And the following automation prevents the house battery from being discharged during lower prices and restricts the discharging to hours with high pricing.
- alias: "EVCC Battery Discharge Control"
initial_state: on
description: >-
Enables or disables the battery discharge control based on Tibber price index
and battery energy percentage by setting `select.evcc_dummy_mode`.
id: ec99e344-2ff0-2405-9570-54784d61d3ea
mode: queued
triggers:
- trigger: homeassistant
event: start
- trigger: event
event_type: automation_reloaded
- trigger: state
entity_id:
- sensor.tibber_price_index
- sensor.tibber_price_discharge_target
variables:
anchors:
- &discharge_control
target:
entity_id: select.evcc_dummy_mode
- &dont_discharge
<<: *discharge_control
alias: "Disable battery discharge"
data:
option: "now"
action: select.select_option
- &allow_discharge
<<: *discharge_control
alias: "Enable battery discharge"
data:
option: "off"
action: select.select_option
action:
- choose:
- alias: "Enable discharge when Tibber price is high"
conditions:
- alias: "Tibber Price Below Dynamic Threshold"
condition: template
value_template: >
{{ states('sensor.tibber_prices') | float > (states('sensor.tibber_price_discharge_target') | float ) }}
sequence:
- *allow_discharge
default:
- *dont_discharge
EVCC provides a switch to turn on/off discharging, but I had troubles using it, so I went the route with the dummy loadpoint.
As long as your house battery is supported by EVCC you can do the same.
Important to know is that EVCC allows for a modbus proxy. Modbus has issues with multiple clients requesting informations from the same modbus device. The proxy is channeling the requests from multiple devices (here EVCC and HA) to my inverter.
Regards
Ralf