What is curtailment? An electricity market expert explains why states sometimes have too much wind or solar power

But other states have restructured their electricity markets so that some companies produce power and others deliver it to customers. In these competitive markets, curtailment raises complex issues. Power generators stay in business by generating and selling power, so when demand drops, grid operators need a system to ensure that they make curtailment decisions fairly.

Often the first tool for choosing which plants to curtail is the prices that generators are paid. When supply grows or demand falls, the price of electricity falls. Some generators may decide that they are unwilling to produce electricity below a certain price and drop off if it hits that level.

If there’s still a power surplus, the organization that operates the grid steps in to manually curtail generators. They can either do this through signals in the grid’s data system or by contacting generators directly through phone calls. Power may be curtailed for five minutes or five hours, depending on how quickly the system returns to normal.

Overall, the U.S. needs more low-emissions electricity to help reduce air pollution and slow climate change. So curtailment isn’t a sound long-term strategy for managing power surpluses. It’s somewhat comparable to the early days of the COVID-19 pandemic when supply chain disruptions forced producers to throw away huge quantities of food even as grocery stores struggled to fill their shelves.

One solution is to expand energy storage so that generators can save excess power for a few hours instead of sending it straight into the grid. Another option is building more transmission to carry power to areas that need it. Both types of investments can reduce the need to curtail generation and forgo making clean, affordable electricity.

This is an updated version of an article originally published on June 22, 2022.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Theodore J. Kury, University of Florida

Theodore Kury is the Director of Energy Studies at the University of Florida’s Public Utility Research Center, which is sponsored in part by the Florida electric and gas utilities and the Florida Public Service Commission, none of which has editorial control of any of the content the Center produces.