Grid Curtailment Yield Losses

ID: fm:grid-curtailment-losses
IRI: https://solarlattice.org/kb/fm/grid-curtailment-losses
Status: active
Category: Grid

Grid curtailment loss happens when the plant could produce more power than it is allowed to export, so available solar energy goes unused. 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 it looks like a flat or controlled output level below what irradiance would support, while inverter and tracker availability look normal, so it is easily mistaken for underperformance. To confirm it, reconstruct available power from irradiance, temperature, inverter status, clipping state and modeled capability, and compare it with meter output, plant controller limits, dispatch signals and curtailment flags. Sort each constrained interval by cause, such as grid dispatch, export limit, economic curtailment, controller behavior, battery charging limit, outage or telemetry error, and at storage sites check whether curtailed energy was charged, clipped or abandoned. Track curtailment separately from equipment losses and use performance metrics built for curtailed plants, because a low performance ratio in curtailed hours does not mean the equipment is unhealthy. Where there is a battery, adjust the charging strategy so it can absorb curtailed energy when it has spare capacity and power headroom.

<!-- review notes

sentence 7: support check: partial - Tuning BESS charging strategy and the recovery conditions (capacity, headroom) are stated, but the passages say only that some curtailed energy may be recoverable, not that the strategy should be adjusted to absorb it whenever spare capacity exists. -->

Claims

`caused_by`

c1 verified · fact Grid operator dispatch

grid curtailment losses sec=h4 h=576525a653a1

verified by: joshuahamsaverified on: 2026-10-16

c2 verified · fact Interconnection constraint

grid curtailment losses sec=h4 h=576525a653a1

verified by: joshuahamsaverified on: 2026-10-16

c3 verified · fact Plant controller command

grid curtailment losses sec=h4 h=576525a653a1

verified by: joshuahamsaverified on: 2026-10-16

c4 verified · fact Negative power pricing

Economic curtailment as a response to negative prices.

grid curtailment losses sec=h4 h=576525a653a1

verified by: joshuahamsaverified on: 2026-10-16

c5 verified · fact Site export cap

grid curtailment losses sec=h4 h=576525a653a1

verified by: joshuahamsaverified on: 2026-10-16

`presents_as`

c6 drafted · lead Flat capped output

Output sits at a flat or controlled level under the power the irradiance would support.

grid curtailment losses sec=h4 h=576525a653a1

c7 verified · fact Low output despite irradiance

Export is held below available plant power while inverter and tracker availability and equipment health look normal.

grid curtailment losses sec=h2 h=5fdb7733fc7c
grid curtailment losses sec=h4 h=576525a653a1

verified by: joshuahamsaverified on: 2026-10-16

c8 drafted · lead Low performance ratio

Low PR in curtailed hours reflects grid instructions more than module, inverter or tracker health.

grid curtailment losses sec=h5 h=d55aa663f3f5

`detected_by`

c9 drafted · lead Setpoint and dispatch review

Review plant setpoints, inverter active power limits, grid operator dispatch signals and curtailment flags.

grid curtailment losses sec=h2 h=5fdb7733fc7c
grid curtailment losses sec=front h=874f05be8763
grid curtailment losses sec=h4 h=576525a653a1

c10 drafted · lead Available power reconstruction

Rebuild available power from irradiance, temperature, inverter status, clipping state and modeled capability, then compare with meter output and controller limits.

grid curtailment losses sec=h6 h=08e6be358742

c11 verified · fact Constrained interval classification

Assign each constrained interval to grid dispatch, export limit, economic curtailment, controller behavior, BESS charging limit, outage or telemetry error.

grid curtailment losses sec=h6 h=08e6be358742

verified by: joshuahamsaverified on: 2026-10-16

c12 verified · fact Battery charging review

At storage sites, check whether curtailed PV energy was charged, clipped or abandoned.

grid curtailment losses sec=h2 h=5fdb7733fc7c
grid curtailment losses sec=h6 h=08e6be358742

verified by: joshuahamsaverified on: 2026-10-16

`mitigated_by`

c13 drafted · lead Loss factor separation

Book curtailment apart from equipment losses.

grid curtailment losses sec=h2 h=5fdb7733fc7c
grid curtailment losses sec=front h=874f05be8763

review note: reviewer 2026-10-19: target mit:separate-curtailment-tracking merged into mit:loss-factor-separation

c14 verified · fact Improved available-power estimation

grid curtailment losses sec=h2 h=5fdb7733fc7c
grid curtailment losses sec=front h=874f05be8763

verified by: joshuahamsaverified on: 2026-10-16

c15 verified · fact Battery charging strategy tuning

Curtailed energy can be partly recovered by DC- or AC-coupled charging only if the battery has capacity, power headroom, control permission and an objective that values the charge.

grid curtailment losses sec=h2 h=5fdb7733fc7c
grid curtailment losses sec=h5 h=d55aa663f3f5

verified by: joshuahamsaverified on: 2026-10-16

c16 verified · fact Curtailment-aware performance metrics

Avoids chasing false equipment faults at plants that are often constrained.

grid curtailment losses sec=h2 h=5fdb7733fc7c
grid curtailment losses sec=h7 h=779bcf6ddc67

verified by: joshuahamsaverified on: 2026-10-16

Referenced by

Curtailment explains c1
Flawed PAN File Yield Losses distinguished_from c12
Granular Dust Soiling Losses distinguished_from c22
Snow Accumulation Yield Losses distinguished_from c18
Tracker Wind Stow Production Losses distinguished_from c11

Grid Curtailment Yield Losses

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Data

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