California Code, Public Utilities Code - PUC § 399.26

(a) In order for the state to meet the requirements of the California Renewables Portfolio Standard Program, substantially increased amounts of electricity generated by eligible renewable energy resources must be integrated with, and interconnected to, the transmission grid that is either owned by, or under the operational control of, the local publicly owned electric utilities and the transmission grid that is under the operational control of the Independent System Operator.

(b) The Independent System Operator and the balancing authority of each area in California shall do both of the following:

(c) The Independent System Operator shall seek any approvals from the Federal Energy Regulatory Commission that are necessary to accomplish the goals and requirements of this article.

(d) In order to maintain electric service reliability and to minimize the construction of fossil fuel electrical generation capacity to support the integration of intermittent renewable electrical generation into the electrical grid, by July 1, 2011, the commission shall determine the effective load carrying capacity of wind and solar energy resources on the California electrical grid.  The commission shall use those effective load carrying capacity values in establishing the contribution of wind and solar energy resources toward meeting the resource adequacy requirements established pursuant to Section 380.