JA ESS’s latest JAPlanet 2.0 series 125 kW/261 kWh ESS features a 125 kW PCS for AC-coupling with the grid
Its JAPlanet Fusion series 125 kW/261 kWh ESS is based on a DC-coupling configuration
The DC-coupled ESS offers an RTE of more than 90%, the company claims
JA ESS, the energy storage arm of JA Solar Technology Co., Ltd., displayed two cabinet-based energy storage systems (ESS) – JAPlanet 2.0 and JAPlanet Fusion – at Intersolar Europe 2026, targeting commercial & industrial (C&I) applications.
Both products include five battery packs, each rated at 52.2 kWh of storage capacity and stacked on top of one another, for a cumulative capacity of 261 kWh. Their nominal output voltage (DC) is 832 V.
While these ESSs share a similar DC-side configuration and components, their coupling with the grid and PV array differs. The JAPlanet 2.0 features a built-in 125 kW silicon carbide (SiC)-based power conversion system (PCS) to AC-couple with the grid. In contrast, the JAPlanet Fusion integrates a 3-phase hybrid inverter to DC-couple with its storage capacity and an on-site PV array.
The AC-coupled 125 kW/261 kWh standalone ESS, when integrated with a new or existing PV array, meets real-time captive demands of up to 125 kW at a full-load current of 180 A via the PCS. At the same time, any excess PV generation will be routed to the storage. Any remaining storage capacity will be charged via grid power. In addition to maximizing clean energy-based consumption, the ESS is also an emergency backup source to ensure uninterrupted C&I operations. It switches to off-grid mode via a static transfer switch (STS) within 20 ms of a grid outage and delivers up to 125 kW of full-load power at 0.5C rate for up to 2 hours or until the battery cut-off voltage limit is reached.
In comparison, the DC-coupled 125 kW/261 kWh ESS’s hybrid inverter directly connects PV array and battery storage to a common DC busbar, eliminating intermediate conversion stages. On the PV side, the inverter supports up to 200% DC/AC oversizing compared to its rated full-load power of 125 kW. Like the model above, it meets captive demand from real-time PV generation, while excess is diverted to storage. During a grid outage, it also switches to off-grid mode and delivers up to 125 kW of power output for up to 2 hours at 0.5C rate or until the battery cut-off voltage is reached. According to the company, the system offers a round-trip-efficiency (RTE) of more than 90%.
Both ESSs also participate in grid-interactive energy management services. To avoid buying costly electricity from the spot market during sudden demand overshoots relative to scheduled load curves, it discharges its storage capacity via the inverter, a process known as peak shaving. Conversely, the storage charges when spot prices and C&I demand fall, known as valley filling.
The AC-coupled ESS can be expanded to a 2.5 MW/5.2 MWh platform by connecting 20 units in parallel, while the DC-coupled counterpart allows up to 10 units to create a 1.25 MW/2.6 MWh system.
