STATEMENT Statement on Vermilion Environmental Commitment IRVING, Texas — June 11, 2018 — Vistra Energy (NYSE: VST) today released the following statement: Near the end of 2010, Dynegy announced its plans to retire its Vermilion Power Station near Oakwood in the first quarter of the following year. Seven years later, the plant is still making headlines. Earlier this year Vistra Energy completed its merger with Dynegy. Vistra, as the new owner of the retired plant, wants to provide an update on the situation in the area, an explanation of what’s happened so far, and an outline of the steps we are taking to close the impoundments in a way that complies with the law and is sufficiently protective of the adjacent Middle Fork of the Vermilion River. Vistra, like Dynegy, is an integrated power generation and retail company. Although Vistra is based in Irving, Texas, Illinois holds a special place in the company’s heart. Vistra has hundreds of employees living and working in Illinois and is proud of its involvement in the communities where the company works and lives. Vistra’s chief executive officer grew up and worked in Illinois for many years, he attended Western Illinois University and the University of Chicago, and his parents, siblings and extended family still live here. Vistra knows firsthand the special meaning and natural beauty the state has to offer, as well as the deserving pride that its residents have in it. Vistra understands the frustration some in the area have about riverbank stabilization work that needs to be done along the stretch of river adjacent to the retired plant site – work that Vistra wants done promptly too. Rest assured: While Vistra inherited this site, as the new owner Vistra is committed to implementing an effective solution. Vistra is working through the regulatory process as swiftly as possible, engaging with the appropriate government agencies, and Vistra is committed to proceeding with a swift and protective closure plan. The river today Some have alleged that the river is being negatively impacted by material from the surface impoundments, but the most recent Illinois Integrated Water Quality Report, issued in 2016, tells a different story. That report confirms that the Middle Fork supports aquatic life. Moreover, even in the face of naturally occurring erosion along the riverbank and historic flooding our impoundments held firm and no material was washed into the river. The regulatory process Vistra is ready, willing, and able to proceed with projects aimed at stabilizing the riverbank and permanently closing the surface impoundments. To do so, however, Vistra must receive the approval of state and federal environmental agencies. Those efforts have been underway and Vistra will continue to push them forward. Vistra is finalizing the last phases of the impoundment closure plan. These plans are subject to Illinois Environmental Protection Agency approval and Vistra will continue to work with them to obtain final approval to close the affected areas. Vistra Energy Statement June 11, 2018 At the same time, Vistra is working with the Illinois Department of Natural Resources to get its input on a riverbank stabilization plan that will be presented to the National Park Service for its review later this month. The National Park Service will then provide its recommendation to the U.S. Army Corps of Engineers, the agency that would issue the permit for the riverbank stabilization plan. The riverbank stabilization technology Vistra will be proposing has already been successfully proven through a project that Dynegy worked on in 2016 along a 485foot stretch of riverbank that abuts company property. How long will all this take? It’s Vistra’s belief that the riverbank stabilization work could be completed in the course of a year once the company is able to begin working. The wild card is the timing of regulatory approvals combined with ongoing intervention by outside groups intent on slowing it down for their own agenda. Our commitment Vistra Energy is committed to environmental stewardship at all its sites. Vistra is proud of its environmental record and strong record of exemplary environmental compliance while meeting or exceeding its obligations. Vistra looks forward to demonstrating its commitment to our fellow citizens of Illinois. Media Meranda Cohn 214-875-8004 Media.Relations@vistraenergy.com About Vistra Energy Vistra Energy (NYSE: VST) is a premier, integrated power company based in Irving, Texas, combining an innovative, customercentric approach to retail with a focus on safe, reliable, and efficient power generation. Through its retail and generation businesses which include TXU Energy, Homefield Energy, Dynegy, and Luminant, Vistra operates in 12 states and six of the seven competitive markets in the U.S., with about 6,000 employees. Vistra’s retail brands serve approximately 2.9 million residential, commercial, and industrial customers across five top retail states, and its generation fleet totals approximately 41,000 megawatts of highly efficient generation capacity, with a diverse portfolio of natural gas, nuclear, coal, and solar facilities.