Maybe. It depends on how long ago the landowner who gave permission sold the property.
When that person gave a "license" (meaning permission) to PG&E to put in the line, it could have revoked the license at any time. For so long as that person owned the property, PG&E acted under that license, so that the 5-year prescriptive easement clock had not started running.
In many states, a conveyance of a property upon which one person has a license revokes the license. In California, the question is unsettled. If the person who granted PG&E revoked it by selling it to someone else, then the 5-year clock started running at that time (assuming everyone knew about PG&E's easement. I recognize it is underground).
Thus if the property was sold more than five-years ago, you may have a problem. But maybe not. You should definitely consult with an attorney to determine what rights you may have.