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A component library#

Several files each say part of a spec and compose into one. The surface declares what the components share. Each component file declares its own math against the surface, and merge makes the spec. Every file here loads and prints on its own, so the unit you pick from is the unit you can read.

The components couple through one flow variable per port, Port_p, so the solved flow at every port can be read back. Where no one reads that flow, a sum that each component adds a term to needs no variable of its own. Compose a spec from several files shows that way.

The names are PyPSA's, spelled Component_attribute as the PyPSA rungs spell them, and the math prints in the symbols those pages use. The spec is cut to dispatch: one build, no availability profile, no ramp limits.

The layout#

examples/library/
  surface.yaml               one flow per port, one balance per bus
  generator.yaml             PyPSA's Generator
  load.yaml                  PyPSA's Load
  variants/
    commitment.yaml          a patch over the composition, not a peer
Page What it shows
The coupling surface the surface, and the sign convention
Generators a file that reads Port_p and prices its output
Loads a file with no variable of its own
The composed spec what merge returns, and the math it prints with each variant

Rules of the layout#

  • One file per thing you would pick on its own. merge takes a whole fragment or none of it, so a spec with no storage never mentions storage.
  • Every component file is written against one surface.
  • Every name carries the component class it belongs to. merge does not rename. Generator_ and Load_ keep the files apart, and the surface owns Port_, port and bus.
  • A fragment is what a system has. A patch is how a component is formulated. A second kind of component is a peer, and merge composes it. A different formulation of one component edits declarations that already exist, and override lays it over the composition.

The variant#

variants/commitment.yaml makes the generator a committed unit. It adds a binary, lifts the upper bound the capacity gave Generator_p, and caps output with a constraint instead.

It edits Generator_p, which generator.yaml introduces, and names Generator_p_nom, which generator.yaml declares. So it is not a spec, and to_spec refuses it on its own. It is laid over the composition:

ms.override(ms.merge(fragments), ['variants/commitment.yaml'])

The composed spec carries the patch and the math it makes, in a tab of its own. That tab is the only place the patch can be read as math.