HollyFrontier Announces Expansion of Renewables Business DALLAS--(BUSINESS WIRE)--HollyFrontier Corporation (NYSE: HFC) (“HollyFrontier”) today announced that its Board of Directors has approved a plan to convert the Cheyenne Refinery to renewable diesel production and to construct a pre-treatment unit (“PTU”) located at the Artesia Refinery. Including the previously announced renewable diesel unit at the Artesia Refinery, HollyFrontier is expected to have a combined capacity to produce over 200 million gallons per year of renewable diesel and pre-tr