NEW YORK (Standard&Poor's) Oct. 17, 2003--Standard&Poor's Ratings Services said today that Calpine Corp.'s (B/Negative/--) plan to build, own, and operate a 525 MW power plant in Mexico does not materially affect the rating, but is slightly credit positive. Calpine will supply two combustion gas turbines from its inventory to the project, giving the company a 45% interest in the facility. Therefore, the project will add contractually based revenues to Calpine's portfolio without depleting cash and diminishing Calpine's liquidity. Mitsui&Co. Ltd. will be the majority owner of the combined-cycle plant at Valladolid in the Yucatan Peninsula. The facility will deliver electricity to Comision Federal de Electricidad under a 25-year power sales agreement. Construction at Valladolid