### Question
How is the term primary fuel defined?


### Answer
The term **primary fuel** is defined in *42 U.S.C. § 7511a* as the following:

> the fuel which is used 90 percent or more of the operating time

#### Citation:
  - *42 U.S.C. § 7511a*
  - Heading: **SUBCHAPTER I-PROGRAMS AND ACTIVITIES > Subchapter Referred to in Other Sections > Part Referred to in Other Sections > Subpart Referred to in Other Sections**

