Lifetime prices for automated fom dispatch#787
Conversation
…n an annualized basis. Merchant plant currently only reads one of two possible inputs, still need to update unit tests
…ices). Fix vartable required variables issues
…lifetime_prices_for_automated_fom
sjanzou
left a comment
There was a problem hiding this comment.
The code changes look fine... please review the project file below for the first test case (PPA below penalty with high escalation rate)
Attached file has two cases
ssc_787.zip
- PPA with suspect results with ppa below penalty for first several years but has a couple of suspect power targets in the following screenshot
- MP with year 1 zeroed out - expected behavior
|
Good question! Discharging is based on: https://github.com/NREL/ssc/blob/f4460db1ab1ea6d3343e8515055f6524f13b60d3/shared/lib_battery_dispatch_automatic_fom.cpp#L235 At the beginning of the PPA simulation, the high value period is worth $0.145 (1.5 TOD factor), so the revenue to discharge equation says discharging is worth $0.0392/kWh. Note that the battery discharges in the first high cost period in the first day. Subsequently, the battery does not charge. Instead, the lifetime degradation slowly reduces the total capacity. This decreases the denominator for SOC, causing SOC to slowly increase:
After enough time, this SOC increase triggers additional discharging (which is even more profitable). Finally the price escalates enough to make revenue to charge > 0, which is when the cycling starts later. If I further lower the PPA price to the point where revenue to discharge is < 0 ($0.05/kWh), we get the expected delay in discharging:
|
sjanzou
left a comment
There was a problem hiding this comment.
Thanks for clarifying the dispatch behavior with the low ppa price and battery discharge spikes.
Recommended tests include:
Fixes NatLabRockies/SAM#894