Cal. Sts. & Hy. Code § 18440
If the city owns or operates or owns and operates a public utility capable of furnishing the improvement provided for in this part, this section may be used as an alternative procedure to that provided in Chapter 6 of this part. The city council by resolution may direct the superintendent of streets, instead of calling for bids and entering into a contract, to issue an interdepartmental purchase order for the improvement of the street lighting system upon such terms as may be agreed upon between the street superintendent and the public utility board or commission. Such purchase order shall not be effective until it is approved by the city council. The interdepartmental purchase order shall state the date on which the improvement shall be started and that it shall continue in force for a period of one year from the effective date thereof.
Ca. Sts. and High. Code § 18440