Curtailment (electricity)

In electric grid power generators, curtailment is the deliberate reduction in output below what could have been produced, in order to balance energy supply and demand or due to transmission constraints. The definition is not strict, and several types of curtailment exist. "Economic dispatch" (low market price) is the most common.
Curtailment is a loss of potentially useful energy, and may impact Power Purchase Agreements. However, utilizing all available energy may require costly methods such as building new power lines or storage, becoming more expensive than letting surplus power go unused.
Examples.
After ERCOT built a new transmission line from the Competitive Renewable Energy Zone in West Texas to the central cities in the Texas Interconnection in 2013, curtailment was reduced from 8-16% to near zero.
In 2018, curtailment in the California grid was 460 GWh, or 0.2% of generation, but increased since. Curtailment of solar power mainly occurs at noon as part of the duck curve.