What is the difference between being an intervenor and providing “public comment”?

An intervenor is a party to a case, with all the rights and responsibilities that entails (See What does it mean to be an intervenor?): ...that entails. .  A person providing public comment is not a party to a case and does not have those rights and responsibilities.

A person who does not desire to intervene, or who is ineligible to intervene, still has an opportunity to provide the Commission information about a case, by providing oral or written public comment or both. 

Public comment, whether made in person or in writing, becomes part of the official docketed record of the case.  Public comment is not admitted as evidence, however, and is not afforded the weight of sworn testimony because public commenters are not under oath and are not subject to cross examination.  Nonetheless, all public comment received is considered by the ALJ and the Commission when considering a case.

A person who is not an intervenor can attend hearings to observe and to provide public comment at the time allotted, but cannot provide any testimony or other evidence or participate in the questioning of witnesses.  To be permitted to question witnesses and provide evidence on the record, a person must file a request to intervene and be granted intervenor status (i.e., party status).