...S&P Global Ratings assigned its '##' rating to Seattle's 2019 series A municipal light and power improvement revenue bonds and series B refunding revenue bonds. The utility does business as Seattle City Light (SCL). The outlook is stable. Seattle pledges the light system's gross revenues to the bonds. The city anticipates using proceeds from the 2019 A bonds to finance capital improvements and conservation programs for the system, fund a reserve fund, and pay the costs of issuance. The city anticipates using series 2019 B proceeds to refund all or a portion of the city's series 2010B bonds. The rating reflects the application of our "U.S. Municipal Retail Electric And Gas Utilities" criteria (published Sept. 27, 2018). The '##' rating further reflects SCL's ability to produce stable coverage and liquidity through various hydrological and economic conditions. Concentration in hydroelectric generation, from both owned assets and power purchases, exposes the city to some surplus sales risks,...