A curtailment is an event where energy services are temporarily unavailable. The term most commonly refers to an end-use customer’s gas service that is interrupted, but it also applies when a renewable electric generator is not allowed to put power onto the grid because it is overloaded.
Gas services are typically curtailed in order of priority. For the distribution grid, services are curtailed in reverse order of the following service priority:
- Residential and small commercial
- Firm large commercial and industrial
- Firm power plants
- Interruptible large commercial and industrial
- Interruptible power plants
So, for example, interruptible power plants would be curtailed first under the above scheme (because they have the lowest priority), with residential and small commercial customers curtailed last. The goal is to ensure that residential and small commercial customers are the highest priority, and thus always have gas service.