Image： China Conch
A 500 MW / 2,000 MWh standalone battery energy storage system (BESS) in Tongliao, Inner Mongolia, has entered commercial operation after a five-month construction period, underscoring China’s rapid deployment of large-scale storage to support high penetrations of wind and solar generation.
Developed and financed by Tongliao Conch New Energy Co., Ltd., a subsidiary of Conch Cement Group – China’s largest cement producer – the project is located in Naiman Banner and is now the largest single-site new-type storage facility in Inner Mongolia. Construction began on June 28, 2025, and the plant completed grid-connection tests and acceptance on November 28, 2025, one month ahead of schedule. Total investment amounted to approximately CNY 1.5 billion.
The installation uses lithium iron phosphate (LFP) battery technology and includes a 220 kV booster substation, enabling direct connection to the region’s high-voltage grid. Annual peak–valley shifting is projected at around 600 GWh, with maximum annual throughput reaching 1.5 TWh – equivalent to roughly 4% of the local marketized electricity volume.
On the AC side, Kehua provides 5 MW centralized PCS–step-up integrated units that combine power conversion and voltage step-up within a single skid, simplifying installation, commissioning, and maintenance. The PCS units carry an IP65 protection rating and are engineered for −35°C temperatures, high winds, and sand exposure typical of eastern Inner Mongolia. According to Kehua, the equipment achieves peak conversion efficiency above 99% and features fan reverse-rotation self-cleaning and modular architecture to reduce manual servicing and enhance fault isolation.
On the DC side, CATL supplies 5 MWh containerized storage systems based on its 314 Ah cells—one of China’s earliest mass-produced 20-ft, 5 MWh solutions. CATL says its end-to-end reliability program—from materials selection and platform standardization to automated production and intelligent testing—reduces safety-failure rates to the parts-per-billion (PPB) level. Over the full lifecycle, the cell platform is expected to deliver 3–5% more discharged energy than comparable products while lowering maintenance costs.
Operating as an independent storage asset within North China’s Mengdong power market, the plant charges during periods of high wind and solar generation and discharges during low-output periods and peak demand. It is designed to provide peak shaving and valley filling, frequency and voltage regulation, ramp-rate smoothing, and power-quality improvements—addressing curtailment and grid-balancing challenges associated with rising renewable penetration in Naiman Banner and surrounding areas.
