AUGUSTA — Maine regulators have approved the merger of the second- and third-biggest electric utility companies in the state.

The Maine Public Utilities Commission today approved a settlement agreement in which Maine Public Service Co. will be acquired by Canadian utility operator Emera Inc., parent of Bangor Hydro Electric Co. Commissioners unanimously agreed that the merger was in the best interest of ratepayers.

Bangor Hydro serves 117,000 customers in five counties. Maine Public Service has 36,000 customers in Aroostook County.

Part of the agreement protects ratepayers in northern Maine from costs associated with any future transmission infrastructure construction.