Behind-the-Meter Solar Accounting in Renewable Portfolio Standards

How does the accounting of behind-the-meter solar photovoltaics (BTM PV) in a state’s renewable portfolio standard (RPS) influence the amount of renewable generation in a region? We show here that the answer depends on two key design elements of a state’s RPS: (1) whether renewable energy certificates (RECs) from BTM PV can be used for compliance and (2) whether load served by generation from BTM PV counts as load covered by the RPS. If load served by BTM PV generation counts toward load and the RECs cannot be used for compliance, generation from BTM PV increases the total renewable generation in the state on a 1:1 basis; however, no state currently implements an RPS in that form. In contrast, under a common RPS design in which BTM PV RECs can be used for compliance and load served by BTM PV generation is not covered by the RPS, the presence of BTM PV and transfer of RECs for compliance can actually decrease the total amount of renewable generation required in the region, relative to a situation in which there is no BTM PV.