California Code, Public Utilities Code - PUC § 2827.8

(a) The eligible customer-generator shall be required to utilize a meter, or multiple meters, capable of separately measuring electricity flow in both directions.Nothing in this section precludes the use of advanced metering infrastructure devices. All meters shall provide “time-of-use” measurements of electricity flow, and the customer shall take service on a time-of-use rate schedule. If the existing meter of the eligible customer-generator is not a time-of-use meter or is not capable of measuring total flow of energy in both directions, the eligible customer-generator is responsible for all expenses involved in purchasing and installing a meter that is both time-of-use and able to measure total electricity flow in both directions. This subdivision shall not restrict the ability of an eligible customer-generator to utilize any economic incentives provided by a government agency or the electric service provider to reduce its costs for purchasing and installing a time-of-use meter.

(b) The consumption of electricity from the electric service provider for wind energy co-metering by an eligible customer-generator shall be priced in accordance with the standard rate charged to the eligible customer-generator in accordance with the rate structure to which the customer would be assigned if the customer did not use an eligible wind electrical generating facility. The generation of electricity provided to the electric service provider shall result in a credit to the eligible customer-generator and shall be priced in accordance with the generation component, excluding surcharges to cover the purchase of power by the Department of Water Resources, established under the applicable structure to which the customer would be assigned if the customer did not use an eligible wind electrical generating facility.