1.2.1. Use Cases That Comport With D.14-05-033 and Options for Compliance The Petition describes two use cases – “no grid charging” (i.e., no grid charging to the storage device) and “no storage export” (i.e., no storage exports to the grid) -- for which CALSSA requests Commission authorization to permit interconnection of DC-coupled solar plus storage systems, as well as to expand compliance options for ACcoupled solar plus storage systems, beyond the three options specified in D.14-05-033. On the latter point, the Petition asserts the current typical means of complying with D.14-05-033, which is to install a net generation output meter (NGOM), can increase project costs by $25,000 and can also increase project timelines by three to six months. For each use case, the Petition discusses several possible configurations and possible compliance pathways. For the “no grid charging” use case, the Petition discusses a voltage-controlled configuration of DC-coupled solar plus storage, a virtual net energy metering (VNEM) configuration, a NEM Aggregation (NEMA) configuration, other unspecified configurations, and ACcoupled solar plus storage systems. The Petition essentially posits that these configurations would ensure the paired storage device is charged exclusively from the NEM-eligible generator and not from the grid. For the “no storage export” use case, the Petition discusses using an inverter or charge controller “with functionality that prevents the storage device from discharging at times when the customer site is exporting power to the grid or install an external relay that provides the same function.” The Petition asserts that this approach would prevent storage exports to the grid. For both use cases, the Petition notes there may be inadvertent but minor instances of either grid import (in the “no grid charging” use case) or storage export (in the “no storage export” use case), which
1.2.1. Use Cases That Comport With D.14-05-033 and Options for Compliance The Petition describes two use cases – “no grid charging” (i.e., no grid charging to the storage device) and “no storage export” (i.e., no storage exports to the grid) -- for which CALSSA requests Commission authorization to permit interconnection of DC-coupled solar plus storage systems, as well as to expand compliance options for ACcoupled solar plus storage systems, beyond the three options specified in D.14-05-033. On the latter point, the Petition asserts the current typical means of complying with D.14-05-033, which is to install a net generation output meter (NGOM), can increase project costs by $25,000 and can also increase project timelines by three to six months. For each use case, the Petition discusses several possible configurations and possible compliance pathways. For the “no grid charging” use case, the Petition discusses a voltage-controlled configuration of DC-coupled solar plus storage, a virtual net energy metering (VNEM) configuration, a NEM Aggregation (NEMA) configuration, other unspecified configurations, and ACcoupled solar plus storage systems. The Petition essentially posits that these configurations would ensure the paired storage device is charged exclusively from the NEM-eligible generator and not from the grid. For the “no storage export” use case, the Petition discusses using an inverter or charge controller “with functionality that prevents the storage device from discharging at times when the customer site is exporting power to the grid or install an external relay that provides the same function.” The Petition asserts that this approach would prevent storage exports to the grid. For both use cases, the Petition notes there may be inadvertent but minor instances of either grid import (in the “no grid charging” use case) or storage export (in the “no storage export” use case), which