Not at all connected to the current line of discussion in this thread but more on general experience from using a home-grown system for optimizing energy usage in our home for a couple of years:
- There must be a functionality for human override. If one take the approach of thinking of this kind of systems as “autonomous advisory systems” rather than “steering systems”, I think the system will get a wider acceptance. The normal mode of operation I have found to be best is a “set and forget” approach, i.e. the normal is that the optimizer does it’s thing and I (or my family) as a user could not care less. But once in a while, you need that washer to do your laundry NOW regardless of energy prices on the spot market. Hence, a human override is essential.
- With the high volatility (variance) of the energy prices it is helpful to consider the energy usage vs time for an appliance. A dishwasher (just to take an example) tends to have two very distinct peaks in it’s power usage. If your optimizer can account for a simple (and optional) profile of power usage of the appliance, the net result will be better optimization in terms of both price and running the appliance ASAP. In my system I have an optional “power vector”, if set the optimizer will use it and most of the time find a better solution, if not set, the optimizer will assume a constant load.
- On the slightly philosophical side: What is “best” price? Is it the lowest total price? Is it time to start? Time to finish? Well, it depends. I don’t care if the washer starts doing the laundry at 23:15 or 02:00 as long as it tells med when it is done and I can hang the clothes to dry. But I would really care if my car is not charged at 07:20 when I am supposed to take the kids to school and go to work. So, in my world, “best” is definitely not always just “cheapest”. But - in order for me (or my system) to make the “best” decision, price is certainly a vital input in the optimization.
- Consider the “when factor”. We humans have a tendency to expect things to happen ASAP. When I close the lid of my dishwasher, I for some reason expect it to do the dishes ASAP. In my system, I have a “time penalty factor” that I can enable when calling the optimizer stating that a cheap solution has to be X% cheaper than an earlier solution (closer to now()) in order to be used. Again, a minimal deviation from the cheapest solution but a function that contributes to increased Family Acceptance Factor of my automation.
- Along that track: communicate the result of the optimizer’s job in the UI. Tell them when the washing machine (or whatever) will start unless they override the optimization. If I start an appliance and it goes dark without any explanation, I tend to wonder if something is wrong. If the UI in openHAB is saying “Laundry expected to start at 03:00, eta 04:30” the number of “Dad - why is the washer dead???” type of questions will be reduced to a minimum.Set and forget.