### Question
Can you define what existing unit means?


### Answer
**Existing unit** is defined as the following in *42 U.S.C. § 7651a*:

> a unit (including units subject to section 7411 of this title) that commenced commercial operation before November 15, 1990

#### Citation:
  - *42 U.S.C. § 7651a*
  - Heading: **SUBCHAPTER I-PROGRAMS AND ACTIVITIES > Codification**

