Elizabeth Twp in Allegheny Co. OKs Invenergy Gas-Fired Plant Allegheny County | Electrical Generation | Industrywide Issues | Pennsylvania | Regulation January 2, 2019January 2, 2019 In January 2016, Invenergy announced their intention to build a natgas-powered electric plant in Elizabeth Township, in Allegheny County (see Invenergy Eyes SWPA for Second Marcellus-Powered Electric Plant). Please Login to view this content. (Not a member? Join Today!) Related