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. [1] [2] [3] The definition is not strict, and several types of curtailment exist. "Economic dispatch" (low market price) is the most common, [4] often coinciding with the low marginal cost of hydropower, solar and wind power. [5]
Curtailment is a loss of potentially useful energy, and may impact power purchase agreements. [6] [7] 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. [8] [9] [10] [11]
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. [12]
Curtailment of wind power in western China was around 20% in 2018. [13]
In 2018, curtailment in the California grid was 460 GWh, or 0.2% of generation. [14] Curtailment has since increased [8] [15] to 150-300 GWh/month in spring of 2020 and 2021, [16] [17] mainly solar power at noon as part of the duck curve. [18]
In Hawaii, curtailment reached 20% on the island of Maui in Hawaii in the second and third quarters of 2020. [19]
In Ireland, 1.2 TWh of wind power was curtailed in 2022. [20] In United Kingdom, 1.35 TWh of wind power was curtailed in early 2023. [21] In Australia, 4.5 TWh of solar and wind power was curtailed in 2024. [22]
Curtailment is a reduction in the output of a generator from what it could otherwise produce given available resources, typically on an involuntary basis
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: CS1 maint: multiple names: authors list (link)CAISO considers three types of curtailment: Economic dispatch, a self-scheduled cut, and exceptional dispatch. These can all happen at the local level, to reduce congestion, or at the system-wide level, to reduce oversupply.
PG&E will effectively shut down projects during public safety power shutoff (PSPS) events, and then not pay the developer for the lost production
In most cases, it simply does not make economic sense to build all the infrastructure (e.g. transmission lines or energy storage) that would be required to utilize every last drop of renewable electricity
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: CS1 maint: archived copy as title (link)the cumulative annual load profile by hour of LDV fleets using its fast charging network — with rideshare vehicles currently making up the lion's share on a gigawatt-hour basis — aligns with the cumulative solar curtailment by hour on the CAISO system
load migration within the existing data center capacity during the curtailment hours in CAISO has the potential to reduce 113–239 KtCO 2e per year of GHG emissions and absorb up to 62% of the total curtailment with negative abatement costs in 2019