Md. Code, Environment § 7–408

(a) A certificate automatically shall be null and void if:

(1) Construction or other preparation of the site for its intended use of the facility for which the certificate was issued has not commenced within 2 years following issuance of the certificate; or

(2) The facility has not commenced operation within 4 years following issuance of the certificate.

(b) The Board may extend the time limits imposed under subsection (a) of this section if the certificate holder:

(1) Applies to the Board for an extension; and

(2) Shows good cause for allowing the extension.