Calpine Corp. promoted Dan Reyneveld to vice president of natural gas operations. He joins the ranks of Charles Chambers and Michael Gerlich, who were named vice presidents upon the recent acquisition by Calpine of Sheridan Energy Inc. Reyneveld was appointed director of gas operations in July 1999. Gerlich, who was vice president and CFO of Sheridan, will continue to oversee the financial operations of Calpine`s newly acquired natural gas division. Chambers is a vice president of business development at Calpine, managing all acquisitions for Calpine Natural Gas, as well as land and legal matters. He previously served as vice president of corporate development at Sheridan.