Wood Mackenzie said the global battery energy storage sector reached a major milestone in 2025, with annual installations surpassing 100 GW for the first time. In response to the market’s growing scale and complexity, the research firm released its first Global Battery Energy Storage System Integrator Comprehensive Ranking, which evaluates suppliers of AC-integrated battery energy storage systems based on performance in the previous calendar year.
The ranking focuses on factory-assembled AC-connected systems that combine the battery, power conversion system, battery management system, thermal management, and control systems in one product. Wood Mackenzie said buyers, including utilities, independent power producers, and developers, are increasingly choosing suppliers not only on technology performance, but also on their ability to manage the full project lifecycle.
Suppliers were assessed across 10 criteria, including technology maturity, research and development, safety, vertical integration, supply chain resilience, environmental, social and governance performance, and financial strength. Sungrow placed first in the 2026 global ranking, followed by Tesla and CATL. BYD ranked fourth, while Envision and Trina Storage shared fifth place. Fluence, LG, Canadian Solar, and Wärtsilä completed the top 10.
Wood Mackenzie said several factors distinguished the leading integrators. Six of the top 10 have more than a decade of battery storage integration experience, highlighting the importance of system design, commissioning expertise, and long-term operational performance as projects become larger and more complex. All of the top 10 manufacture at least one critical component, such as battery cells, power conversion systems, or battery management systems, which can improve compatibility and reduce execution risk. Eight of the top 10 exceeded the firm’s benchmarks for system efficiency and lifetime cycle performance, while nine invested more than 4% of annual revenue in research and development in 2025. Nine also reported positive profitability.
Wood Mackenzie said 18 manufacturers received its Grade A designation, reflecting the continued maturation of the BESS industry. The firm added that leading suppliers are expanding their manufacturing footprint globally to address changing trade policies and local content requirements while maintaining safety certifications and thermal management standards.
Source: Wood Mackenzie
