Our vision is to be the first-choice provider for customers seeking energy solutions in the complex and changing energy marketplace. Constellation Energy is... A Fortune 125 competitive energy company based in Baltimore. The nation’s leading supplier of competitive electricity to large commercial and industrial customers. One of the nation’s largest wholesale power sellers. A major generator of electricity with a diversified fleet of power plants strategically located throughout the United States. A regulated distributor - our Baltimore Gas and Electric utility - of electricity and natural gas in Central Maryland.