Question: What hydroelectric system is operated by the utility district that provides electricity to Sacramento County and a small portion of adjacent Placer County in California?
Sentence (from "Sacramento Municipal Utility District"): It is one of the ten largest publicly owned utilities in the United States, generating the bulk of its power through natural gas (estimated 56% of production total in 2009) and large hydroelectric generation plants (22% in 2009).
Relevant evidence: No