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 agreement
A power purchase agreement (PPA), or electricity power agreement, is a contract between two parties, one which generates electricity (the seller) and one which is looking to purchase electricity (the buyer). The PPA defines all of the commercial te ...
s.
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
The Electric Reliability Council of Texas, Inc. (ERCOT) is an American organization that operates Texas's electrical grid, the Texas Interconnection, which supplies power to more than 25 million Texas customers and represents 90 percent of the st ...
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 Inter ...
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
Lawrence Berkeley National Laboratory (LBNL), commonly referred to as the Berkeley Lab, is a United States Department of Energy National Labs, United States national laboratory that is owned by, and conducts scientific research on behalf of, t ...
'', 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 is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV) or indirectly using concentrated solar power. Photovoltaic cells convert light into an electric current using the photovoltaic e ...
at noon as part of the duck curve
The duck curve is a graph of power production over the course of a day that shows the timing imbalance between peak demand and renewable energy production. Used in utility-scale electricity generation, the term was coined in 2012 by the Califor ...
.[
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 be ...
Battery storage power station
A battery storage power station is a type of energy storage power station that uses a group of batteries to store electrical energy. Battery storage is the fastest responding dispatchable source of power on electric grids, and it is used to sta ...
*Energy forecasting Energy forecasting includes forecasting demand ( load) and price of electricity, fossil fuels (natural gas, oil, coal) and renewable energy sources (RES; hydro, wind, solar). Forecasting can be both expected price value and probabilistic forecasti ...
, including forecasting for price
A price is the (usually not negative) quantity of payment or compensation given by one party to another in return for goods or services. In some situations, the price of production has a different name. If the product is a "good" in the c ...
, wind
Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hou ...
and solar
References
{{Reflist
External links
Increase in curtailment in California, 2014—2022
Curtailment curves in South Australia
peaking at 69% (Christmas 2021)
Electrical engineering