In the
electric power industry, curtailment is an involuntary reduction of the electric generator output ("dispatch down") made to maintain the
grid stability (for example, for the
grid balancing). While curtailment is a standard technique that had been applied throughout the history of electric power production, in the 21st century it became an economic issue for the owners of wind
and solar generators. These
variable renewable energy plants, due to the absence of an expendable resource (like fuel), have quite low
marginal cost of the electricity production, so curtailment affects the economics of the project in a much more significant way than in the case of conventional units.
Curtailment is a loss of potentially useful energy, and may impact
power purchase agreements.
However, using 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
The Texas Interconnection is an alternating current (AC) power grid – a wide area synchronous grid – that covers most of the state of Texas. The grid is managed by the Electric Reliability Council of Texas (ERCOT).
The Texas In ...
in 2013, curtailment was reduced from 8-16% to near zero.
[Wiser, Ryan H., and Mark Bolinger.]
2014 Wind Technologies Market Report
page 38. '' Lawrence Berkeley National Laboratory'', August 2015.
Curtailment of
wind power in western China was around 20% in 2018.
In 2018, curtailment in the
California grid was 460 GWh, or 0.2% of generation.
Curtailment has since increased
[ to 150-300 GWh/month in spring of 2020 and 2021,]solar power
Solar power, also known as solar electricity, is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV) or indirectly using concentrated solar power. Solar panels use the photovoltaic effect to c ...
at noon as part of the duck curve.[
In Hawaii, curtailment reached 20% on the island of Maui in Hawaii in the second and third quarters of 2020.]
Mitigation options
*Transmission upgrade[
*]Demand response
Demand response is a change in the power consumption of an electric utility customer to better match the demand for power with the supply. Until the 21st century decrease in the cost of pumped storage and batteries, electric energy could not b ...
price
A price is the (usually not negative) quantity of payment or compensation expected, required, or given by one party to another in return for goods or services. In some situations, especially when the product is a service rather than a ph ...
, wind
Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...
and solar
References
Sources
* {{cite web, first1 = Lori , last1 = Bird , first2 = Jaquelin , last2 = Cochran , first3 = Xi , last3 = Wang , title=Wind and Solar Energy Curtailment: Experience and Practices in the United States
, url=https://docs.nrel.gov/docs/fy14osti/60983.pdf , ref= , date = March 2014 , publisher=NREL , access-date=2025-05-20
External links
Increase in curtailment in California, 2014—2022
Curtailment curves in South Australia
peaking at 69% (Christmas 2021)
Electrical engineering