Revision/rename nominal value

[p-snft]

I think, the capacity of a Flow (e.g. a power line) is actually easier to interpret as the "nominal value". Actually, I have been asked that quite some times. If we have a nominal_capacity of a Flow, it would be arguable why it's nominal_storage_capacity for the GenericStorage. So we need to say either nominal_flow_capacity which is actually redundant. In my opinion, it makes sense to call both nominal_capacity.

In fact, they are quite similar. In particular, they both accept a number (fixed capacity) or an Investment object.

[jokochems]

@p-snft I had a look and introduced some fixes and suggestions.

I have some doubts concerning the renaming for the storage which is a consequence of the fact that the English term "capacity" similarly to the German term "Kapazität" can have different meanings.

For storages, we have a value in MWh, while for flows, we have a value in MW or whatever energy resp. power unit. Both are named "capacity", though, which might be slightly misleading, esp. for unexperienced users.

Maybe, one idea would be to rename to something like nominal_energy for storages to make the physical dimensions clearer.

But anyways, feel free to decide on how to proceed with the renaming.

[p-snft]

@p-snft I had a look and introduced some fixes and suggestions.

I have some doubts concerning the renaming for the storage which is a consequence of the fact that the English term "capacity" similarly to the German term "Kapazität" can have different meanings.

For storages, we have a value in MWh, while for flows, we have a value in MW or whatever energy resp. power unit. Both are named "capacity", though, which might be slightly misleading, esp. for unexperienced users.

Maybe, one idea would be to rename to something like nominal_energy for storages to make the physical dimensions clearer.

But anyways, feel free to decide on how to proceed with the renaming.

Storages only have energy, Flows only have power. Thus, I think harmonisation is more beneficial than having different names. For both, the name is "nominal_capacity", both accept a value or an Investment object. Also, "energy" should not be a keyword. In fact, we do not enforce units. For example, you could have a storage with a certain mass of hydrogen or wood pallets. It still represents energy, but the unit does not match (we are off by a factor c² XP).