NEW YORK (Standard&Poor's) June 14, 2012--Standard&Poor's Ratings Services has assigned its 'AA-' rating to Seattle, Wash.'s municipal light and power improvement and refunding revenue bonds, series 2012A and 2012B; and improvement revenue bonds, series 2012C. At the same time, Standard&Poor's affirmed its 'AA-' rating on the system's parity lien debt and its 'AA-' underlying rating on the debt. The outlook is stable. The 2012C bonds will be sold as New Clean Renewable Energy Bonds (CREBs). The system does business as Seattle City Light (SCL). "The rating reflects our opinion of a low-cost hydro-based generation portfolio that can meet demand even under below-normal water conditions," said Standard&Poor's credit analyst Peter Murphy. The rating