WAYNESBORO, Ga. (AP) — The first new U.S. nuclear reactor built from scratch in decades has begun generating electricity.

Plant Vogtle’s new Unit 3 began generating power in March and is scheduled to reach commercial operation by June. Unit 4 is scheduled to be complete in early 2024.

Lead owner Georgia Power Co. says the reactors are a success. But the project is $17 billion over budget and seven years late.

It was supposed to be part of an early 2000s nuclear power renaissance, but two reactors in South Carolina were abandoned and no others have been built.

Georgia Power’s residential customers will begin paying an additional $3.78 per month as soon as Unit 3 achieves commercial operation. But the final bill won’t come until Unit 4 is complete.