Munson founded Vulcan Power Co. in 1991, and served as its president, CEO and chairman until new directors, appointed by the new investors, ousted him in October and fired him on November 20.
Vulcan Power officials say the complaint is without merit while investors declined to comment.
Munson portrays himself in the lawsuit as a visionary entrepreneur who built up privately held Vulcan Power so that it had one of the largest geothermal portfolios in the country.