Edgar F. Peterson, president and chief executive officer of National Permanent Bank, will assume the additional post of chairman of the Washington bank. He succeeds John Stadtler, who will become vice chairman. In addition, Josephine R. Millett was promoted to executive vice president for retail banking.

Wilbur R. Cross, president and chief financial officer of Suburban Savings & Loan Association, announced he will take on the additional responsibilities of chairman of the board of the Annandale financial institution. He replaces James L. McIlvaine Sr. who will remain a member of the board.

Eden Hannon & Co., an Alexandria financial services firm, has named Larry J. Scully vice president of energy ventures and privatization and Sanford J. Selman manager of energy development. Scully, formerly with Peat Marwick Mitchell & Co., will direct the firm's financing of energy and environmental projects.

Riggs National Bank has promoted Walter A. Howell, a vice president for operations, to senior vice president. In other actions, Riggs promoted nine to vice presidents: Bradley K. Alford, Mary L. Anderson, Eleanor D. Bierbower, Walter M. Cart Jr., Stanley W. Starr and Frederic B. Underwood, in commercial banking; Frederick A. Morse, in real estate; and Jo B. Troth and David E. Isner, in finance.