Cal. Pub. Util. Code § 2813
The private energy producer shall be required to provide and to pay the total cost of the interconnection as well as any costs associated with providing a transmission capacity sufficient to handle that portion of the energy generated by the private energy producer that is over and above the capacity otherwise required by the public utility to service its utility customers and meet other authorized commitments. The public utility shall not be required to construct any additional electric or gas facilities on its system or to acquire any real property by eminent domain or otherwise for such facilities, in order to perform the service contemplated by this chapter unless the cost of such additional facilities or acquisitions are to be borne by the private energy producer.
Ca. Pub. Util. Code § 2813