Maryland Code, Public Utilities § 3-110

(1) attend a proceeding before the Commission, if ordered by the Commission, a commissioner, or the Executive Secretary of the Commission; and

(2) give any relevant testimony or produce any relevant evidence, if ordered by the Commission, a commissioner, or an authorized hearing examiner.

(b)(1) If a person refuses without valid cause to comply with an order issued under subsection (a) of this section, on affidavit that sets forth the violation to a court of general jurisdiction, the Commission or a commissioner may apply for an order to show cause why the person should not be held in contempt.

(2) An order issued under paragraph (1) of this subsection shall be returned to the court that issued the order, not less than 2 days and not more than 5 days after the date of issue.

(3) On the return of an order issued under this subsection, if the court determines that the person has violated subsection (a) of this section and persists in the violation, the court may hold the person in contempt.

(c)(1) A person may not refuse to comply with subsection (a)(2) of this section on the ground that giving testimony or producing evidence may tend to incriminate or subject the person to penalty or forfeiture.

(2) Except for perjury committed by an individual giving evidence before the Commission, an individual may not be prosecuted, punished, or subjected to penalty or forfeiture for producing any evidence required under subsection (a) of this section.