EXHIBIT 21.1 METRETEK TECHNOLOGIES, INC. LIST OF SUBSIDIARIES Southern Flow Companies, Inc., a Delaware corporation PowerSecure, Inc., a Delaware corporation Metretek, Incorporated, a Florida corporation Metretek Europe Limited, a Great Britain company Sigma VI, Inc., a Florida corporation Metretek Contract Manufacturing Company, Inc., a Florida corporation Marcum Gas Transmission, Inc., a Colorado corporation Marcum Capital Resources, Inc., a Colorado corporation PowerSpring, Inc. a Delaware corporation Mercator Energy Incorporated, a Colorado corporation Marcum Denver, Inc., a Colorado corporation