Md. Code, Public Utilities § 3–106

(a) If a person timely files, the person may apply to intervene in a proceeding before the Commission.

(b) The Commission shall grant leave to intervene unless the Commission concludes that:

(1) the parties to the proceeding adequately represent the interest of the person seeking to intervene; or

(2) the issues that the person seeks to raise are irrelevant or immaterial.

(c) (1) An intervenor has all the rights of a party to a proceeding.

(2) In a proceeding before the Commission, an individual who is an intervenor may represent himself or herself.