Add documentation discussing storage scheduling use cases in more detail

[Flix6x]

By now we have accumulated quite some scheduling options (see https://flexmeasures.readthedocs.io/en/latest/api/notation.html#flex-model, and https://flexmeasures.readthedocs.io/en/latest/api/v3_0.html#post--api-v3_0-sensors-(id)-schedules-trigger)) that aren't really explained in detail anywhere else. I suggest we add a new documentation section (e.g. to https://flexmeasures.readthedocs.io/en/latest/tut/forecasting_scheduling.html or to https://flexmeasures.readthedocs.io/en/latest/api/notation.html#flex-model) where we can discuss some scheduling problems. There we can then also address the case detailed in #575, and what the client can do to set up this problem as a feasible scheduling problem. This will require some combination of using the soc-maxima and soc-minima fields, instead of the soc-max and soc-targets fields. Something like:

• setting soc-maxima to a list of values equal to the normally preferred maximum value, for each time step, but excluding some time range around each soc-target (to make the problem feasible),
• setting the soc-minima to a list of 100% values, for each soc-target datetime.

Originally posted by @Flix6x in #680 (comment)

And from #679: The storage efficiency field could also use some more explanation. For example, a storage efficiency of 99 percent per (absolute) day, for scheduling a 1-hour resolution sensor, should be passed as a storage efficiency of 0.99**(1/24).

[victorgarcia98]

Good idea 😄

I think we should have a major section for scheduling and different subpages for, not exclusively, explaining the following:

• The general model, i.e., linear_optimization.py (constraints, cost function, variables...)
• StorageScheduler, input parameters, how does it fill the constraints (i.e. maxima, minima, min, max, storage losses...)
• Use cases, i.e how to use the input parameters to describe some real life situations (e.g. use minima to approximate to a target SOC, how to model availability of a EV, ...).

[nhoening]

Just noting that this is a high-value issue in my mind.
Scheduling is the reason why FlexMeasures exists, so the explanations here mean a lot.

Examples help users. We have the API docs and the tutorial which both handle an example but the docs should be the place where someone can start. Maybe a little repitition wouldn't hurt, even. For instance, what's in the API documentation often isn't read by non-developers.

[nhoening]

I see two PRs for this:

• Main conceptual section for scheduling, types of schedulers, use cases
• Latex model of the linear programming model in the storage scheduler and shifting scheduler