Curtailment Loss Calculator
Curtailment is when a grid operator orders a wind farm to reduce output below what the available wind resource could actually produce — typically because of transmission congestion, oversupply, or grid stability constraints. It is becoming a structural risk for wind developers, not just an occasional inconvenience, as renewable buildout continues to outpace grid capacity. This calculator takes your available (uncurtailed) annual energy production, curtailment rate, and PPA/market price, then reports the curtailed energy, the actual delivered energy, and the annual revenue left on the table. Start with the uncurtailed production from our Annual Energy Production Calculator, then weigh the lost revenue against a revenue-stacking strategy like co-located battery storage — and remember that curtailed energy is exactly the kind of otherwise-wasted power the Wind-to-Data Center Co-Location Sizing Calculator model is designed to capture.
The energy the project would produce over a year with no curtailment — typically from your Annual Energy Production estimate.
EIA data shows ERCOT curtailed about 5% of available wind generation in 2022, and projects that could rise to 13% by 2035 without major transmission upgrades. Actual rates vary significantly by region and grid congestion.
The contracted PPA price or expected wholesale market price per megawatt-hour, used to value the curtailed energy.
available annual energy production (MWh/year) × (curtailment rate (%) ÷ 100)
available annual energy production (MWh/year) − curtailed energy (MWh/year)
curtailed energy (MWh/year) × PPA/market price ($/MWh)
Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.
How we calculate this →Curtailment is becoming a structural risk for wind developers, not just an occasional inconvenience. EIA's own analysis found ERCOT curtailed about 5% of available wind generation in 2022 -- and without major transmission upgrades, that figure could climb to 13% by 2035 as renewable buildout continues to outpace grid capacity. At an 8% curtailment rate, a 100,000 MWh/year project loses 8,000 MWh annually, worth $280,000 at a $35/MWh PPA price -- money left on the table before accounting for any additional revenue-stacking strategy like co-located battery storage that could help capture some of that otherwise-curtailed energy.
How curtailment loss is calculated
This calculator estimates the energy and revenue a wind project loses to curtailment, tying three inputs together: the available (uncurtailed) annual energy production, the curtailment rate, and the PPA/market price. Three quantities tie the calculation together.
Curtailed Energy (MWh/year) = Available (Uncurtailed) Annual Energy Production (MWh/year) × (Curtailment Rate (%) ÷ 100). Curtailment is when a grid operator orders a wind farm to reduce output below what the available wind resource could actually produce, typically because of transmission congestion, oversupply, or grid stability constraints. The curtailment rate is the share of available generation that gets cut, so multiplying the uncurtailed annual production by that share gives the total energy lost over the year. At the defaults (100,000 MWh/year, 8% curtailment), that is 100,000 × (8 ÷ 100) = 100,000 × 0.08 = 8,000 MWh/year curtailed.
Actual Delivered Energy (MWh/year) = Available (Uncurtailed) Annual Energy Production (MWh/year) − Curtailed Energy (MWh/year). This is the energy the project actually delivers to the grid and gets paid for after curtailment. At the defaults, that is 100,000 − 8,000 = 92,000 MWh/year delivered.
Annual Revenue Lost to Curtailment ($) = Curtailed Energy (MWh/year) × PPA/Market Price ($/MWh). Valuing the curtailed energy at the contracted PPA price or expected wholesale market price converts the lost megawatt-hours into dollars — the revenue the project forgoes each year because the grid could not accept its output. At the defaults (8,000 MWh curtailed, $35/MWh), that is 8,000 × 35 = $280,000 in annual revenue lost.
Two notes on the model. First, the curtailment rate is a single annual average; real curtailment is highly variable by hour, season, and grid condition, and some regions now see multi-hour or multi-day curtailment events that an annual percentage smooths over. Second, whether a developer actually bears the full financial impact depends on contract structure — some PPAs include curtailment compensation provisions, while merchant projects selling into wholesale markets typically absorb the full loss with no compensation. Co-located battery storage can absorb energy that would otherwise be curtailed and discharge it later, though most of today's battery fleet is built for short-duration cycling, which does not fully address longer curtailment events. Data sources: EIA (Energy Information Administration) wind curtailment data and grid congestion analysis; ERCOT, PJM, and regional transmission operator curtailment reports; wind farm PPA pricing data from NREL and utility-scale wind project case studies; battery storage co-location and curtailment mitigation strategies from energy storage research and project case studies; regional wind resource and transmission capacity data from NREL and transmission planning studies. Verification: with defaults (100,000 MWh available, 8% curtailment, $35/MWh), Curtailed Energy = 8,000 MWh/year, Actual Delivered Energy = 92,000 MWh/year, Annual Revenue Lost to Curtailment = $280,000.