search

NREL / SAM

System Advisor Model (SAM)
BSD 3-Clause "New" or "Revised" License
345 stars 141 forks source link

Provide losses to PV Smoothing, and add UI warnings to increase alignment with gen #1065

Open brtietz opened 2 years ago

brtietz commented 2 years ago

PV smoothing still has some discrepancies between PV Smoothing Outpower (the output used to calculate violations) and System Power Generated (the final power output of the simulation). A major cause of this is that losses are not provided to the PV Smoothing algorithm. In the defaults case, this causes a constant, 1% difference in output power.

There are two other inputs that need to be set properly for these outputs to align. The user should get warnings to prevent issues: • The “minimum time at charge state” input on the dispatch page being shorter than the ramp interval • If simulating a DC connected battery, the inverter efficiency cutoff could cause trouble.

brtietz commented 2 years ago

Best to do https://github.com/NREL/SAM/issues/1146 first, so that we can do stronger output comparisons while solving this issue. Moving to patch 1.

brtietz commented 1 month ago

Additional source of large discrepancies: PV smoothing uses the same power number for charging and discharging. In the default case (DC sized battery) these can be different by a factor of 8% due to AC and DC losses.

Battery losses appear to already be included in PVSmoothing output power, AC wiring losses are not included.

brtietz commented 1 month ago

Availability losses for the battery are an issue. The battery attempts to charge, availability losses reduce the amount of PV available, battery reduces charging, and so-on in a loop. It probably doesn't make sense to fix this until https://github.com/NREL/SAM/issues/985 splits the PV and battery availability losses.