Home/American Shipper/Trillium and AMP join to build CNG fuel stations in U.S. American Shipper Trillium and AMP join to build CNG fuel stations in U.S. FreightWaves Staff · Tuesday, July 24, 2012 Facebook Twitter Pinterest LinkedInTrillium CNG, a business unit of Integrys Energy Group, and AMP Americas will together put in place a full network of compressed natural gas (CNG) filling stations across the U.S., beginning with two highways in Texas.