Calpine ( CPN ) Thursday forecast a fourth-quarter loss that's much larger than the consensus estimate of analysts. The San Jose-based power company said it expects a fourth-quarter GAAP loss of 48 cents to 56 cents a share, vs. the Thomson First Call consensus of a 14 cents-a-share loss. Calpine said the guidance estimate includes a pretax, noncash gas reserve impairment charge of approximately $200 million. EBITDA -- or earnings before interest, taxes, depreciation and amortization -- as adjusted for non-cash and other charges, will be approximately $200 million to $250 million for the quarter. Calpine reports financial results on Feb. 24.