Ala. Code § 37-1-43

All the authority, powers and jurisdiction which have been given by law to the Alabama Public Service Commission over utilities engaged in intrastate commerce in this state are hereby given to said commission over utilities whose principal place of business is located outside the State of Alabama, but who are engaged in this state in interstate commerce not regulated under the acts of the Congress of the United States to the extent that the exercise by said commission of such authority, powers and jurisdiction over such utilities engaged in interstate commerce is permissible.