Add battery O&M and self-discharge

[lixiangk1]

• Add battery O&M in $ / kW-installed and $ / kWh-installed, defaulted to $0
• Add battery self-discharge as a fraction per day loss based on stored kWh, defaulted to 0.0

[adfarth]

@lixiangk1 could you add a little explanatory text here for this input?

[lixiangk1]

Hey! Did you mean add notes in the code to better define this term or just explain it in the pull request?

The input is a loss term for battery self-discharge, entered as a daily fraction for how much of the stored kWh is leaked from the battery (e.g., 3% of the the kWh stored in the battery is self-discharged per day). This is then modeled as a per timestep loss term where eg. 0.03/24/timesteps_per_hour * dvStoredEnergy is subtracted from dvStoredEnergy at every timestep.

[adfarth]

I mean adding a comment "# explanation" in the code here so that it appears in the REopt.jl documentation (https://nrel.github.io/REopt.jl/dev/reopt/inputs/#ElectricStorage). We haven't really done this for ElectricStorage inputs but for all of the other techs we've been including some help text around the inputs. If you could do the same for the O&M costs that would be great! Maybe with a note about not double-counting replacement and O&M costs.

[adfarth]

@lixiangk1 Three quick comments from an initial review!

• Could you please update the CHANGELOG?
• Could you investigate why the tests are failing and try to get all tests to pass?
• Could you add a test to runtests.jl for both the O&M costs and the self-discharge?

[lixiangk1]

@adfarth Thanks for your review! Do the latest changes address your comments? As for the tests, it seems that the Windows/MacOS ones are passing but the Ubuntu ones timeout - do you know why that might be happening? Is it something specific to this branch?

[adfarth]

@adfarth Thanks for your review! Do the latest changes address your comments? As for the tests, it seems that the Windows/MacOS ones are passing but the Ubuntu ones timeout - do you know why that might be happening? Is it something specific to this branch?

Recapping our convo here!

• Expected that the ubuntu tests will fail so if the others are passing it's all good (but my latest merge of develop into this branch did seem to cause some to break :( )
• Going to double check that a "self discharge fraction based on stored energy per time step" makes practical sense
• Then, rename variable and help text, adjust calculation in the constraints
• Test/document difference in results if discharge is applied to previous timestep's stored energy vs current one

[Bill-Becker]

@lixiangk1 any plans to finish this? I could probably support with a charge code in Q1.