Glossary of concepts

[nhoening]

PR #65 made first progress in clearing up how we talk about FlexMeasures' concepts of flexibility and its role.

However, we can add more clarity. Here are a few terms which need better definition. Once we agreed on these and written down, the next step is to look through the documentation and use them throughout (replace alternative wordings)

Main concepts:

• flexibility
• flexibility opportunities
• activation of flexibility (opportunities)

Crucial inputs and outputs (this list needs to be shorter):

• forecasts / baseline
• schedules
• flexible schedules
• forecasted schedule / suggested schedule (vs all possible fllexible schedules)
• scheduled deviation

[nhoening]

Also, the concepts of what constitutes flexibility is not clear enough. The benefits-of-flex page says:

Energy flexibility can come from the ability to store energy ("storage"), to delay (or advance) planned consumption or production ("shifting"), the ability to lower production ("curtailment"), or the ability to increase or decrease consumption ("demand response") ― see Types of flexibility for a deeper discussion.

But then later we only talk about shifting and curtailment as actions in the deeper discussion. What about concepts like "storage" and "demand response"? Are they different kinds of flex opportunities, or even distinct actions? In any case, it would be bad not to mention these concepts, and we're not sure that everything can be boiled down to shifting and curtailment (though a lot of the interesting things can - ramping from gas generators might not be interesting for us and also not replacement through other energy types).

One can go as deep as one likes in this.

• USEF doesn't seem to bother too much. They have a nice sentence though: "If consumers are flexible about whether and when to use energy, they could reduce grid stress and their own energy bills." Then, they move on to the potential values of flex, which is good selling.
• TNO somewhere described 4 types of flexible assets (e.g. storage, buffer, ...) as I recall from the Hegrid project, but I can't find them anymore.
• Felix published an ISGT Europe paper where another classification is made [1].

We need to find a way that is straightforward and fair. Absolute truth or precision are not our goals here.

[1]
Ramping:

• Capacity in kW/h (fast or slow)
• Effort in kW (up or down)
  Loading:
• Capacity in kW (up or down)
• Effort in kWh (plus or minus)
  Stalling:
• Capacity in kWh (plus or minus)
• Effort in kWh² (left or right)

[Flix6x]

TNO somewhere described 4 types of flexible assets (e.g. storage, buffer, ...) as I recall from the Hegrid project, but I can't find them anymore.

This ended up evolving into S2.