### Question
How is the term ultracapacitor defined?


### Answer
The term **ultracapacitor** is defined in *42 U.S.C. § 17231* as the following:

> an energy storage device that has a power density comparable to a conventional capacitor but is capable of exceeding the energy density of a conventional capacitor by several orders of magnitude

#### Citation:
  - *42 U.S.C. § 17231*
  - Heading: **CHAPTER 152-ENERGY INDEPENDENCE AND SECURITY > SUBCHAPTER V-ACCELERATED RESEARCH AND DEVELOPMENT > Part D-Energy Storage for Transportation and Electric Power**

