OPERATION_MODES
===============

Confine the device's power to one of several power ranges at every time step.
Each operation mode declares a signed power range (positive is consumption, negative is production).
This is useful for devices that cannot modulate their power freely, such as a device that is either off or running at some minimum power (or at one fixed power).
Terminology and semantics follow the `operation modes of the S2 standard <https://docs.s2standard.org/model-reference/FRBC/FRBC.OperationMode/>`_.
Declaring operation modes introduces binary decision variables into the optimization problem (making it a mixed-integer linear program), which may increase solve times.
Each operation mode may optionally declare a ``fixed-cost``: a no-load / commitment cost (in the flex-context currency) that is incurred at every time step during which that mode is active.
This models the running cost of keeping a unit on regardless of its output (e.g. a generator's full-speed-no-load fuel burn, or a boiler's standing cost). When omitted, the fixed cost is 0.