LONGi and RWE Sign 300 MWh Battery Energy Storage Project

LONGi Solar, a global leader in solar technology, has officially signed a landmark agreement with RWE, a key strategic customer, to deliver a massive utility-scale photovoltaic (PV) and battery energy storage system (BESS) project in Italy. Totalling approximately 300 MWh of energy storage capacity, the grid-connected installation marks a key milestone in customer trust, showcasing LONGi’s rapid evolution into a tier-one provider of integrated, full-stack clean energy solutions globally.

For this project, LONGi will provide its flagship utility-scale storage solution: the LONGiBank 2.0 6.25 MWh. Engineered as an all-in-one, highly safe liquid-cooled LFP system, this next-generation solution boasts an exceptional energy density of up to 146 Wh/L, packing 6251 kWh of capacity in an optimized 20-foot container footprint.

To ensure maximum safety and reliability on the grid, the system features a multi-level fuse electrical design alongside AI-driven thermal runaway prediction for active fire prevention. Furthermore, its advanced AI-controlled temperature management system extends the system’s service life, while integrated high-precision health diagnostics streamline full-chain operations and maintenance (O&M) to deliver a market-leading Levelized Cost of Storage (LCOS).

This high-efficiency system, deployed in a 4-hour storage configuration, perfectly aligns with the Italian National Grid’s peak shaving and ancillary services requirements. This milestone agreement reinforces LONGi’s rapid expansion of its BESS business across Europe and worldwide, backed by a legacy of reliable products and innovative solutions.

Unlocking the Italian energy transition

As Italy accelerates toward its National Integrated Plan for Energy and Climate (PNIEC) goals, storage is no longer optional; it is the bedrock of the transition. High-capacity BESS projects are vital to mitigate the intermittency of solar generation, stabilize the Italian national grid, and ensure that clean, affordable energy is dispatchable even during peak non-solar hours.

“This agreement with RWE is a profound vote of confidence in LONGi’s technological vision,” says Leon Zhang, President of LONGi Europe. “We are proving that solar-plus-storage is no longer an alternative addition but the primary foundation of the future power grid. This 300MWh project in Italy represents the dawn of a new era where high-efficiency PV and intelligent storage work as a single, dispatchable power source, paving a reliable path for Europe’s complete energy independence.”

As Leon Zhang has already said in discussions about LONGi’s evolving utility-scale roadmap, the European market is quickly moving from volume-centric transactions to partnership-centric ecosystems.

“Customers expect long-term partnerships that safeguard project economics and optimize the levelized cost of electricity (LCOE). This is exactly why we introduced our LONGi ONE solutions, to seamlessly combine PV and BESS in direct response to Europe’s soaring demand for highly integrated, co-located clean energy assets.”

Redefining Solar-Storage with the “LONGi ONE” Strategy

At the heart of this cooperation is LONGi’s newly launched LONGi ONE strategy, a revolutionary approach that overcomes the traditional multi-vendor “accountability gap” in solar-plus-storage projects:

One System: fully self-developed, natively integrated PV and BESS systems that redefine the core logic of solar-plus-storage. The LONGi ONE solutions architectures achieve an industry-leading 93% system round-trip efficiency, a full four percentage points higher than standalone, piecemeal setups.
One Platform: an intelligent, collaborative software control layer (OneSync / OneOS) powered by AI. Its patented Intelligent Cell Connection System (iCCS) monitors cells in real-time, predicting potential risks three to six months in advance to maximize asset longevity, reduce operational downtime, and boost investor ROI.
One Responsibility: a comprehensive turnkey solution and integrated operation and maintenance (O&M) service model. LONGi stands as the single point of contact for the entire lifecycle of the asset, erasing the finger-pointing typical of multi-vendor projects.

This holistic approach directly addresses a critical market pain point. As previously detailed by Dennis She, Vice President of LONGi, “Energy storage is now a foundational pillar of the global transition, but historically, customers have had to piece together disparate components from different suppliers.” Mr. She also detailed that “While these parts are connected on-site, they are rarely coordinated. That is the exact gap LONGi ONE bridges. By coordinating the PV generator, the BESS, and the power conversion system (PCS) from day one, we optimize the performance, communication, and overall economics of the entire system. Because these systems are built to operate for over 20 years, having a single, financially robust vendor handle the integrated system, service standards, and warranty is a game-changer for project reliability.”

To support this commitment locally, LONGi is rolling out its strategic “2815 Plan.” By the end of 2028, LONGi will establish 15 comprehensive local Service Centers of Excellence (CoEs) across major European markets, expanding from its initial hub in Madrid. These hubs will provide 360-degree, localized engineering, commissioning, and spare-parts support to ensure rapid response times and absolute peace of mind for strategic partners like RWE.