261kWh Modular Units Paralleled to 2MWh Energy Storage System – Project Overview

System Overview

This project employs 8 units of 125kW/261kWh liquid-cooled energy storage integrated cabinets operating in parallel, forming a total system capacity of 1MW / 2MWh. Through standardized energy storage modules, the system can be flexibly configured to meet various industrial, commercial, and grid-side storage requirements.

System Configuration

Core Capability: In-House EMS with VPP Compatibility

The core value of this project lies not only in the hardware configuration but also in Sanhe Power Tech's self-developed EMS (Energy Management System). The system features the following key capabilities:

1. Self-Developed EMS – Full-Stack Proprietary

Sanhe Power Tech holds complete intellectual property rights for its EMS software platform, covering the full chain from data acquisition, strategy optimization, to cloud-based management. The system leverages AI algorithms for load forecasting and dynamic charge/discharge strategy optimization, supporting millisecond-level power data acquisition and real-time monitoring. The EMS has been validated across multiple projects for its stability and economic performance, effectively supporting fine energy management for user-side storage applications.

2. Seamless Compatibility with PV EMS

The system adopts standard communication protocols (Modbus TCP/RTU, CAN 2.0), enabling data exchange and coordinated control with various photovoltaic plant EMS platforms. Whether for new solar+storage projects or retrofitting existing PV plants, Sanhe's storage system can be integrated via AC or DC coupling to achieve smooth PV output, surplus energy storage, and curtailment reduction. This compatibility has been validated across multiple projects, supporting integration with leading third-party PV monitoring platforms.

3. VPP Aggregation and Electricity Market Participation

The system is pre-configured with VPP (Virtual Power Plant) aggregation interfaces, allowing distributed storage resources to participate in electricity markets. Through its open control architecture, the EMS can receive grid dispatch signals and respond within milliseconds, supporting frequency regulation, peak discharge, and other ancillary services. This design transforms storage assets from "cost centers" into "revenue-generating units."

Solution Advantages

1. Modular Design, Flexible Expansion

Each 261kWh cabinet operates as an independent unit, allowing flexible configuration based on project requirements. The 2MWh scale is achieved through 8 standard modules operating in parallel, meeting current capacity needs while enabling smooth future expansion by adding additional cabinets. This approach has been successfully deployed in a PV storage project in the Czech Republic, where 8 × 125kW/261kWh liquid-cooled units (1MW/2MWh) effectively support solar peak shaving and dynamic power trading.

2. High Energy Density, Space Efficiency

The 261kWh liquid-cooled cabinets feature a compact design with a footprint of approximately 1.5–1.8 m² per unit. The total footprint for 8 units is approximately 12–15 m², significantly less than traditional container solutions. This configuration has been validated in multiple projects. For example, a 2MWh project at industrial Park in Malanshan, China, using 8 × 261kWh cabinets, occupies only 12 m² and saves the park approximately RMB 800,000 (USD123000.00)annually in electricity costs.

3. Parallel Operation, High System Reliability

Multi-cabinet parallel grid-forming is a recognized industry challenge, including three key technical barriers: uneven circulating current, synchronization failure, and system oscillation. The project addresses these with proven control strategies:

VSG Parallel Pre-Synchronization Strategy: Frequency compensation is added to the active power loop, enabling smooth paralleling of multiple PCS units and reducing inrush current and power oscillation during parallel connection.

Voltage Compensation & Circulating Current Suppression: Voltage compensation is added to the reactive power loop of each VSG to ensure consistent output voltage across units and reduce circulating current.

String-Type Architecture: Each PCS independently controls a single battery cluster, avoiding system-wide failure if one unit fails, unlike centralized architectures.

For the 2MWh scale, 8 × 261kWh cabinets can be paralleled directly at the 400V low-voltage side without additional step-up transformers, simplifying system architecture while improving overall reliability.

4. Liquid Cooling Thermal Management, Extended Lifespan

Each 261kWh cabinet is equipped with a liquid cooling thermal management system, ensuring cell temperature difference is maintained within 3°C, extending system cycle life to over 6,000 cycles. Compared to air cooling, liquid cooling offers higher heat dissipation efficiency, improving overall system efficiency by approximately 2–3%.

5. Wide Application Adaptability

Technical Specifications Summary

Reference Project Cases

Case 1: PV Storage Project – Czech Republic

8 × 125kW/261kWh liquid-cooled cabinets in parallel, total capacity 500kW/2MWh. Through Sanhe Power Tech's self-developed EMS, the system achieves coordinated control with the PV plant, effectively supporting peak shaving and dynamic power trading. The project validates the system's reliability and economic performance in the European electricity market environment.

Case 2: Technology Park, Malanshan, China – 2MWh Project

8 × 261kWh cabinets, total footprint only 12 m². Using Sanhe's EMS with peak-valley arbitrage strategy, the system saves approximately RMB 800,000 (USD123000)annually in electricity costs. The system is also pre-configured with VPP interfaces for future participation in electricity market trading.

Conclusion

The 8 × 261kWh modular parallel configuration to form a 2MWh system has been validated across multiple projects for technical feasibility and economic returns. This solution offers modular flexibility, efficient liquid cooling, and high system reliability through parallel operation — making it an efficient choice for industrial and commercial energy storage as well as small-to-medium grid-side projects. Sanhe's in-house EMS further enhances system intelligence, transforming storage assets from "backup devices" into "smart revenue-generating units" capable of participating in electricity markets through AI-driven optimization, PV coordination, and VPP aggregation.

About Sanhe Power Tech

Sanhe Power Tech has over 20 years of experience in the power electronics industry, specializing in power quality management and energy storage system integration. The company's products are widely deployed across industries including oil & gas, semiconductor manufacturing, data centers, and renewable energy generation, offering full lifecycle services from solution design, equipment supply, to operations and maintenance support.

Contact Us:
yvonne.zhang@samwha-cn.com
www.sanhenergy.com
+86-13418990147

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