The Enphase Storage System is now a UL1741 PCS (Power Control System) certified system, per NFPA 70, NEC 2020. The Ensemble PCS functionality includes several modes which protect connected components from overload. This can potentially save customers costly equipment installations in two scenarios: Production Metering Requirements, and Main Panel Upgrades.
An innovation in the Enphase Ensemble system has addressed a costly concern for potential battery storage system owners. Due to certain production metering requirements, some utilities require an NGOM "net generation output meter" for ESS with more than 10kW of power output. Fortunately, the “ESS import only” mode within the Ensemble PCS functionality obviates the need for a costly NGOM, and in some cases even avoids the encumbrance of transformer upgrading. However, for systems lacking an output limiting PCS, a growing number of utilities are requiring an NGOM to be installed if an energy storage system (ESS) has an output of 10 kW (power) or greater. This requirement is currently found in California utilities, such as Pacific Gas & Electric (PG&E), San Diego Gas & Electric (SDG&E) and South California Edison (SCE).
Additionally, the PCS functionality within the Ensemble system can in some cases save the customer from an expensive main panel upgrade. The Main Panel Busbar Rating is often a limiting factor for PV and ESS installations. Upgrading the main panel can be a challenging process and requires a certified electrician on-site, which can altogether add a cost of several thousand dollars to a project. PCS Integration in the Enphase Ensemble system employs smart real-time current sensing to monitor and limit the current fed back to the main panel, thereby eliminating the need for a Main Panel upgrade. In this way the “Main Panel Upgrade (MPU) Avoidance” mode within the Ensemble PCS functionality enables the installation of larger systems while at the same time ensuring the main panel remains compliant with NEC requirements.
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