Energy, Inc. (Sunverge), OutBack Power Technologies (OutBack), and Charles Hewitt filed comments. On November 8, 2013, Outback, SDG&E, CALSEIA, SolarCity, CESA, SCE, PG&E, ORA, IREC, Sunverge, and Charles Hewitt filed reply comments. On January 6, 2014, Commissioner Michael Peevey issued a subsequent ACR to solicit additional input into safety considerations for the interconnection of energy storage systems. On January 8, 2014 SCE, ORA, SDG&E, Charles Hewitt, Elke Brazel, CESA, IREC and SolarCity filed comments in response to the January 6, 2014 ACR. NEM Eligibility The October 17, 2013 ACR explained that storage devices paired with NEM-eligible generation facilities that meet the Guidebook requirements may exempt from interconnection application fees, supplemental review fees, costs for distribution upgrades, and standby charges as additions or enhancements to NEM-eligible systems under the current NEM tariff. These exemptions would apply to any storage device connected behind the same billing meter as the NEM generating system because this configuration meets the conditions of the "directly connected energy storage" category as described in the Guidebook. However, in order to preserve the integrity of NEM, or in other words, in order to ensure that NEM credits can only be generated by eligible renewable electric generation, the ACR proposed that qualifying systems meet certain configuration and metering requirements. To achieve this goal, the ACR suggested that the metering requirements in the NEM Multiple Tariff (NEM-MT) serve as the standard to ensure that only NEM-eligible generation receives NEM credit. Under the NEM-MT provision, the customer-generator must 1) install a non-export relay on the non-NEM generator(s); 2) install Net Generation Output
account the need to preserve NEM integrity and storage sizing limits. IREC asks the Commission to limit the size of storage systems relative to NEMgenerators based on the amount of energy stored in the battery relative to the daily peak output NEM-generator. They provide an example of a 4 kW PV system that has a maximum daily output of 50 kWh (kilowatt hour) and suggest that the sizing requirement be based on this kWh quantity plus expected losses, for a maximum size of 58 kWh. IREC contends this approach would be easier to implement and more equitable. PG&E and SDG&E support sizing limitations. PG&E suggests that the Commission modify the size capacity limits proposed and instead limit storage system size based on the lesser of the NEM-eligible generator capacity or the customer maximum demand. SDG&E also suggested the Commission modify the size capacity limits proposed. SDG&E proposed that the storage system be sized to the AC nameplate of the NEM-generator’s inverter and from an energy perspective that the storage device should be no larger than the energy production of the NEM-generator on a single day. Outback suggested a sizing capacity limit of not more than 12:1 in terms of maximum discharge power to maximum renewable generator power. Outback contends this ratio would be sufficient to allow the generator to produce enough energy in a single day to match typical energy needs and round trip efficiency losses while also meeting the instantaneous power needs of the local loads being leveled or reduced. ORA suggested that the sizing limit be consistent with current SGIP requirements. Discussion The goal of this requirement is to set sizing requirements that ensure that the NEM-paired storage system is sized in such a way that it primarily functions to augment the value of the NEM-generator. With that in mind, IREC and SDG&E’s site