Curtailment

Curtailment is the deliberate reduction or halt of electricity generation or consumption below what would otherwise be available, usually ordered by a grid or transmission operator to keep supply and demand in balance in real time. On the generation side, wind and solar projects get curtailed when their output would exceed what the local grid can absorb, a growing problem in markets with fast renewable buildout, where curtailment can strip a meaningful share of a project's annual output and revenue. On the consumption side, large loads such as data centers can be asked to curtail, or reduce draw, during grid stress events — either voluntarily under a demand-response program or, under some newer interconnection agreements, as a mandatory condition of connecting at all. "Curtailable" or "flexible" interconnection is emerging as a way for utilities to connect data centers faster by granting capacity that can be dialed back during peak stress rather than guaranteeing firm power at all times.