Analyze grid curtailment risk by TSO region and technology
Total US Curtailment
~23.5 TWh
ERCOT Curtailment Rate
5.9%
CAISO Curtailment Rate
3.8%
Revenue Impact
$2–5/MWh
Total annual curtailment by ISO region (GWh, 2024 approximate)
Seasonal variation — spring wind and summer solar peaks
Wind vs solar share of total US curtailment
Wind
15,550 GWh (66%)
Solar
7,950 GWh (34%)
Total: 23,500 GWh
Hourly curtailment distribution — solar peaks midday, wind overnight
Curtailment rates by ISO and technology (2024, approximate)
| ISO | Technology | Annual Curtailment | Rate | Primary Cause | Trend |
|---|---|---|---|---|---|
| ERCOT | Wind | 10,200 GWh | 6.8% | Transmission congestion (West Texas–load centers) | +1.2% YoY |
| ERCOT | Solar | 4,800 GWh | 4.5% | Midday oversupply / negative pricing | +2.1% YoY |
| CAISO | Solar | 2,400 GWh | 4.2% | Duck curve oversupply (11am–3pm) | +1.8% YoY |
| CAISO | Wind | 550 GWh | 2.1% | Local congestion / minimum generation | Flat |
| SPP | Wind | 3,200 GWh | 5.1% | Transmission congestion / export limits | +0.9% YoY |
| SPP | Solar | 400 GWh | 2.3% | Localized congestion | Flat |
| MISO | Wind | 1,600 GWh | 3.2% | Transmission constraints / low demand periods | +0.6% YoY |
| MISO | Solar | 350 GWh | 1.8% | Local congestion | Flat |
Values are approximate and derived from public ISO reports and market data. Actual curtailment varies by node and interconnection point.
ISO-level risk profiles, storage mitigation, and transmission outlook
West Texas / Panhandle
Curtailment Range
5–8%
Severe transmission congestion between generation-rich West Texas and load centers (Dallas, Houston, Austin). CREZ lines at capacity.
$3–5/MWh effective reduction in realized price
Co-located 2-hr BESS can reduce effective curtailment by 40–60% via time-shifting. 4-hr systems capture >80% of curtailed energy.
ERCOT Long-Term System Assessment identifies $4–6B in new 345kV lines by 2030, but permitting delays likely push completion to 2032+.
Central Valley / Desert Southwest
Curtailment Range
3–5%
Duck curve oversupply drives midday curtailment. Minimum generation constraints from gas fleet exacerbate solar clipping.
$2–4/MWh effective reduction in realized price
4-hr BESS is the primary mitigation — shifts solar to evening ramp. California mandates effectively require co-located storage for new solar.
SB 100 driving $15B+ grid investment through 2035. New HVDC lines to Nevada/Arizona could increase export capacity.
Oklahoma / Kansas Wind Corridor
Curtailment Range
3–6%
Wind fleet growing faster than transmission buildout. Export limits to MISO/ERCOT binding during high-wind periods.
$2–4/MWh effective reduction in realized price
2-hr BESS provides moderate benefit (20–35% curtailment reduction). Wind profile less concentrated than solar — longer duration storage needed.
SPP ITP process approved $3.8B in new transmission. Key 345kV projects target 2028–2030 COD.
Upper Midwest / Great Plains
Curtailment Range
2–4%
Moderate transmission constraints, mostly local. MISO Long Range Transmission Plan addresses most bottlenecks.
$1–2/MWh effective reduction in realized price
BESS value lower given moderate curtailment. Primary battery economics driven by capacity market and ancillary services rather than curtailment avoidance.
MISO LRTP Tranche 1 ($10.3B, 18 projects) underway. Tranche 2 ($17B+) in planning. Best-in-class transmission planning among US ISOs.
Data Sources & Methodology
Curtailment figures are approximate and based on publicly available ISO reports: ERCOT State of the Grid (2024), CAISO Managing Oversupply reports, MISO and SPP market monitoring data. Individual project curtailment varies significantly by node, interconnection agreement, and local congestion patterns. Revenue impact estimates assume average wholesale power prices in each ISO.