Solana Beach took another step Wednesday toward becoming the first city in San Diego County to provide its residents with a renewable alternative to electricity provided by San Diego Gas & Electric Co. City Council members agreed to enter the second of three phases that would lead to the creation and operation of a community choice aggregation, or CCA, as early as next year through a partnership with two private companies that would oversee its maintenance and operation. Other cities would be welcome to join the partnership, they said.