Curtailment means a PV plant is allowed to export less power than it could actually produce. The limit can come from grid operator dispatch, an interconnection constraint, a plant controller command, a response to negative prices, or a site export cap. In the data, output stays flat or at a controlled level below what the irradiance would support, while inverter and tracker availability look normal. Because the equipment is healthy, curtailment is easy to mistake for underperformance, and it pulls down the performance ratio during the curtailed hours. To diagnose it, rebuild the available power from irradiance, temperature, inverter status and clipping state. Compare that with meter output, setpoints and dispatch signals, then sort each constrained interval by cause. Monitoring tools such as PowerTrack detect curtailment from the control signal sent to the inverters. They count the loss as expected output minus actual output only while the plant is following its setpoint. At PV-plus-storage sites, some curtailed energy can go into a DC-coupled or AC-coupled battery. This only works if the battery has room, power headroom, control permission and an objective that values the charge. Track curtailment separately from equipment loss and use curtailment-aware KPIs, so crews do not chase equipment faults that are not there.
explainsc1 drafted · lead Grid Curtailment Yield Losses
Curtailment holds export below what the plant could produce, so realized energy drops even though equipment is healthy.
sec=h1 h=158275ff7629sec=h2 h=5fdb7733fc7csec=h4 h=576525a653a1c2 drafted · lead Flat output below available power
Under curtailment, output sits flat or at a controlled level below the power the irradiance would support.
sec=h4 h=576525a653a1c3 drafted · lead Low performance ratio
A low PR during curtailed hours may come from grid instructions, not from module, inverter or tracker health.
sec=h5 h=d55aa663f3f5related_toc4 drafted · lead Performance ratio
The usual approach is to exclude curtailed periods and calculate a non-curtailed PR. This needs careful analysis when curtailment applies more than 50% of the time.
sec=h5 h=d55aa663f3f5sec=h24 h=68d475d606d5c5 drafted · lead Grid operator dispatch
One possible source of the limit.
sec=h4 h=576525a653a1sec=h24 h=68d475d606d5c6 drafted · lead Interconnection constraint
One possible source of the limit.
sec=h4 h=576525a653a1c7 drafted · lead Plant controller command
One possible source of the limit.
sec=h4 h=576525a653a1c8 drafted · lead Negative power pricing
Curtailment can be a response to negative prices.
sec=h4 h=576525a653a1c9 drafted · lead Site export cap
One possible source of the limit.
sec=h4 h=576525a653a1c10 drafted · lead Limit maximum active power
Curtailment loss occurs when the inverters are commanded to limit their power output.
tbl=10.r3 h=7bfdbf807e8dsec=h5 h=3b77a534f0f4c11 drafted · lead Inverter clipping
Both inverter saturation and curtailment produce capped output. Clipping state is one input when reconstructing available power.
sec=1.2.3 h=426525e43b7dsec=h6 h=08e6be358742review note: support check: partial - Saturation and curtailment are discussed and clipping state is an input to available power reconstruction, but the passages don't state both produce capped output as a relation.; review: partial - The passages say saturation holds output at a maximum and list clipping state as an input to reconstructing available power, but they never say curtailment itself produces capped output.
c12 drafted · lead Availability
Proactive curtailment can reduce availability.
sec=1.2.3 h=426525e43b7dc13 verified · fact Available power reconstruction
sec=h6 h=08e6be358742verified by: review-workflowverified on: 2026-10-24
c14 drafted · lead Curtailment-aware performance metrics
sec=h2 h=5fdb7733fc7csec=h7 h=779bcf6ddc67c15 drafted · lead Improved available-power estimation
sec=h2 h=5fdb7733fc7cc16 verified · fact Battery charging strategy tuning
sec=h2 h=5fdb7733fc7cverified by: review-workflowverified on: 2026-10-24
c17 verified · fact DC-coupled storage
Some curtailed energy can be recovered through battery charging if the battery has capacity, headroom, control permission and an objective that values the charge.
sec=h5 h=d55aa663f3f5verified by: review-workflowverified on: 2026-10-24
c18 verified · fact AC-coupled storage
Some curtailed energy can be recovered through battery charging under the same conditions.
sec=h5 h=d55aa663f3f5verified by: review-workflowverified on: 2026-10-24
c19 drafted · lead Curtailed energy not stored
At storage sites, track whether curtailed PV energy was charged, clipped or abandoned.
sec=h6 h=08e6be358742c20 drafted · lead AlsoEnergy PowerTrack platform and API
PowerTrack calculates curtailment loss as expected output minus actual output while the site is following the control setpoint.
tbl=10.r3 h=7bfdbf807e8dsec=h5 h=3b77a534f0f4sec=front h=10001d881d82related_to c7related_to c1related_to c6