Capstone Turbine Corp. announced Monday the appointment of Robert Flexon, the former chief executive of Dynegy Inc., as its new chairman.Flexon replaces Holly Van Deursen who will continue to serve on the board of the Van Nuys microturbine manufacturer as an independent director.Flexon was chief executive of Dynegy, the Houston electricity company, until its 2018 acquisition by Vistra Energy. He also served as chief financial officer and chief operating officer of NRG Energy Inc., an energy company with headquarters in New Jersey and Texas.Flexon thanked the members of the Capstone board, on which he has served since 2018, for placing their confidence in him as the new chairman.“I am extremely optimistic about this company’s future and am eager to take on the role of chair to guide Capstone to even greater successes,” Flexon said in a statement.Shares of Capstone (CPST) closed down 47 cents, or more than 4.4 percent, to $10.23 on the Nasdaq.