As utility-scale PV plants continue to expand and energy storage becomes more essential than ever, system architecture is playing a critical role in boosting efficiency, cutting costs, and ensuring grid stability.

Medium-Voltage (MV) coupling offers a highly flexible approach to integrating PV and energy storage systems (ESS). It delivers efficient power transmission, simplified layout, and outstanding adaptability for both new-build and retrofit applications.

In this edition, we explore two large-scale PV + ESS configurations that leverage advanced inverter, battery, and power conversion technologies to drive higher efficiency, lower lifecycle costs, and enhanced grid support.

Scheme 1: 7/9.1MW PV Array + 9.6MW/20MWh ESS (314Ah)

This solution features a 7/9.1MW PV array integrated with a 9.6MW / 20MWh energy storage system utilising 314Ah battery cells. By connecting both systems on the MV side, it enables highly efficient, coordinated operations for utility-scale plants.

• PV Side: High-power string inverters paired with a large-scale array configuration maximise power generation while reducing equipment count and system complexity.

• Energy Storage Side: The MV coupling architecture allows the ESS to connect smoothly with the PV plant. It requires no extensive modifications to the existing setup, significantly lowering retrofit costs and construction complexity.

• Core Design: An integrated PCS (Power Conversion System) and step-up transformer design optimises the power transmission path, ensuring stable energy conversion and seamless grid integration.

Scheme 2: 8/12.5MW PV Array + 6.25MW/12.5/25MWh ESS (588Ah+)

This solution features a 512kW inverter layout combined with a 12.5MW / 25MWh energy storage system. Designed around a large-subarray topology, it optimises the system layout to boost power generation and effectively lower the Levelised Cost of Energy (LCOE) over the plant's lifecycle.

• Next-Gen Battery Cells: Battery containers are equipped with 500+Ah large-capacity cells.

• Smart Control: A refined 'one-cluster-one-management' strategy eliminates circulating currents between battery clusters, significantly improving charging and discharging efficiency.

• Grid Resilience: The 3.125 / 6.25MW integrated PCS and step-up transformer unit uses a two-stage architecture. This provides robust high-voltage ride-through capability, preventing grid disconnection during fluctuations and enhancing overall operational safety.

By combining high-efficiency PV generation, precise storage management, and a highly integrated MV architecture, this solution delivers a more reliable and cost-effective MV coupling option for utility-scale developers.

Field Application: 4.8MW/10MWh MV Coupling Retrofit in Italy

The real-world benefits of MV coupling are already on display in San Severino Marche, Italy, where a 4.8MW / 10MWh energy storage system has been integrated into an operational PV plant.

Instead of a costly redesign of the entire PV system, the ESS was added as an independent subsystem on the medium-voltage side. This approach highlights the immense flexibility of MV coupling, allowing owners to upgrade existing solar assets with minimal changes to the original plant architecture.

With the addition of the ESS, the project now optimises solar generation, enhances energy dispatch flexibility, and elevates the power plant's overall performance.

This project demonstrates how MV coupling provides a practical, high-value pathway for upgrading existing PV plants into highly flexible PV + ESS power systems.

Built for the Next Generation of PV + ESS Plants

From optimised system topology and high-efficiency power conversion to advanced battery management and stronger grid support, MV coupling is unlocking new possibilities for utility-scale solar.

By integrating PV and energy storage through a smarter, more flexible architecture, Chint Power is helping plant owners maximise energy value while reducing system complexity and lifecycle costs.

More renewable energy. More flexibility. One integrated solar + storage solution.

CHINT POWER: To Build the Leading Smart PV+ESS Generator