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

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Theodore J. Kury, University of Florida

(THE CONVERSATION) Curtailment has a special meaning in electric power systems. It describes any action that reduces the amount of electricity generated to maintain the balance between supply and demand – which is critical for avoiding blackouts.

Recently, curtailment has made news in states like California and Texas that are adding a lot of wind and solar power. On very windy or sunny days, these sources may produce more electricity than the grid can take. So grid managers reduce production to manage that oversupply.

This can be a lost opportunity. Electricity from solar and wind, as well as existing nuclear plants, is inexpensive and emits less greenhouse gases than fossil fuels, so it may be in society’s interest to keep these generators running.

A special kind of surplus

Consumers know about shortages and surpluses in the goods they buy. Shortages mean that shoppers can’t get that PlayStation 5 for Christmas – or, more critically, the bread, water or baby formula they need.

Surpluses look different, like unsold books...