Hydro storage reservoir sizing with discrete increments of generator capacity

[nmgeek]

I know there are limits to what can be modeled with LP constraints: I wonder if there is a way to set up constraints so a pumped hydro storage (PSH) reservoir (MWh) is optimally sized AND capacity (MW) is calculated in increments of available hydro pump/generator units, for example in increments of 250MW.

If you model new PSH as stor_new_lin then the optimal reservoir size is calculated. But the capacity is not constrained to be a multiple of pump/generator unit capacity.

If you model new PSH as stor_new_bin then I assume you will get a capacity that is an increment of your pump/generator unit capacity. However, in this case the gridpath model constraints require that you set a fixed reservoir capacity (in the binary_build_size_mwh field).

Ideally, you would be allowed to leave binary_build_size_mwh empty and gridpath would calculate optimal reservoir size.

[anamileva]

I would suggest that this be a new capacity type. The rationale behind the capacity and operational types architecture is that users are able to easily do exactly things like this including niche features that may not be part of the main repository (as there's a cost to maintaining the functionality).