California Governor Jerry Brown recently signed a new law that could significantly expand virtual net energy metering in California. Since 1996, California utility customers owning renewable energy systems have been able to offset their electricity bills with credits earned by feeding power generated by their systems back to the utility. SB 594 amends California’s net metering law to allow customers to aggregate energy consumed at multiple meters located on their property (or on their contiguous property) and net that use against the power produced by the customer’s renewable facility on the same site.

Meters on contiguous properties must be solely owned, leased, or rented by the eligible customer-generator to be included. Parcels divided by a street, highway, or public thoroughfare are considered contiguous provided that they are otherwise contiguous and under the same ownership. The customer-generator will be able to use the sum of the load of the aggregated meters for purposes of establishing the maximum size renewable generation system to be used for net metering purposes. However, the existing maximum size limit (1 MW) for net-metered generation facilities will apply to customer-generators aggregating multiple meters. Overall, expanded virtual net metering would provide a way for many customers with multiple meters to use on-site generation more efficiently and economically.

Implementation of SB 594 is contingent upon the California Public Utilities Commission (CPUC) making a determination that the expanded virtual net metering program established by the bill will not result in costs being shifted to non-participating ratepayers. The CPUC is required to make this determination by September 30, 2013.

Meanwhile, virtual net metering is currently available on a limited basis in California. Meters may be aggregated for net metering purposes on multi-tenant and multi-meter properties served by investor owned utilities so long as the meters are served by a single service delivery point. This limitation generally means that virtual net metering is only viable for certain types of multi-meter properties (e.g. apartment buildings). Utility virtual net metering tariffs may be somewhat more flexible for customers participating in the Multifamily Affordable Solar Housing program. More complex multi-meter properties like farms and vineyards likely will have significantly expanded opportunities to take advantage of meter aggregation if/when SB 594 is implemented.