Thanks @mstormi for pointing this thread to me!
I’m interested in joining forces with other contributors and contribute in writing a binding for fetching day-ahead prices from Entso-E Transparency Platform’s API, see discussion on planing of that Binding at Entso-E binding for Nordpool spot prices
I created this solution last July: Control a water heater and ground source heat pump based on cheap hours of spot priced electricity - #13 by masipila
I really like the idea that this aWATTar binding does in terms of allowing users to define these configurable “Cheapes xx hours”.
The use cases that I currently have are:
- Find cheapest consecutive xx hours for charging an electric vehicle
- Find cheapest consecutive yy hours for heating domestic hot water with a boiler
- Find cheapest zz hours for heating the house
- Visualization of when the big loads are ON so that I know not to schedule our dish washer / washing machine to be ON at the same time. We have “only” 3x35A main fuses so if all 5 big loads (car, boiler, heat pump, dish washer, washing machine) are ON at the same time, the fuse of phase 1 would be overloaded. I schedule the dish washer and washing machines manually with their own timers.
Point 1: I don’t need to charge the car every night and the number of needed hours is different between the nights. I have currently created an Item called “CarChargingHours” which I can use to select how many hours I want. Updating this Item triggers calculation of the cheapest consecutive slot with a lenght of my choice.
Point 2: I don’t need to heat the domestic hot water every night. We have enough capacity to skip two nights if there is no cheap hours. I have DS18B20 sensors in the boiler which allows me to monitor how much hot water is left. I currently have a habit of checking the Finnish wind power production forecast (10 days ahead) to see if there are cheaper (or more expensive) nights coming. This forecast is available at Sähkön hintapuntari - Foreca.fi. I have an Item called “WaterHeatingHours” which allows me to select the number of hours for the next day. Updating this Item triggers the calculation to find the cheapest consecutive slot for the heating.
Point 3: This is the most complex / advanced of my use cases.
I fetch the weather forecast from the Finnish Meteorology API. I combine tomorrow’s forecasted temperature points with tomorrow’s wind speed points and derive a “wind chill compensated temperature”. This is the “feels like” temperature that you might be familiar with in weather forecasts. The formula is available at Wind chill - Wikipedia.
Based on the “feels like” or “wind chill compensated temperature”, I calcualte how many hours of heating our house needs tomorrow. The result of this calculation is stored to an Item called “HeatingHours” and I can manually adjust it if needed. Updating the value of this Item (either the scheduled calculation or manual adjustment) triggers the calculation of which hours the house heating will be ON. These hours do not need to be consecutive.
If tomorrow is very cold, my algorithm will divide the day into 3x8h parts and finds the cheapest hours from each 8h “slice” so that it’s guaranteed that each 8h part will have at least some heating hours. This way I avoid a situation that could otherwise easily occur that I would not have any heating in ~15 hours in a row, which would cause the house to cool too much.
As mentioned, I would like to contribute in designing the ultimate kick-ass solution concept which could be used with multiple different spot price sources, whether it’s Entso-E (most of Europe) or country-specific or company-specific data sources.
Cheers,
Markus