Research firm Wood Mackenzie has published its first ranking of the world's top makers of grid batteries — the large battery systems that utilities and power companies install to store electricity, not the kind homeowners put in their garage. The ranking covers "integrators," companies that build complete battery systems combining the battery, power electronics, and safety controls into one unit. Sungrow topped the list, followed by Tesla, CATL, and BYD. Rounding out the top ten were Fluence (the other US company), South Korea's LG, Finland's Wärtsilä, and several more Chinese firms. Six of the ten companies are Chinese.
The report notes that global battery storage installations passed 100 gigawatts in a single year for the first time in 2025, a sign of how central these systems have become to power grids. Wood Mackenzie says buyers now pick suppliers based on more than price: companies that make their own core components, invest heavily in research, and can show years of installation experience are pulling ahead. Most of the top ten have over a decade of experience, make at least one major component themselves, and are turning a profit — factors that matter for long-term reliability and warranty support.
None of this changes anything about home energy upgrades directly. These are utility-scale systems, not home battery products. But the ranking gives a sense of which battery makers are financially stable and technically strong industry-wide, which is useful background if you're ever comparing brands for a home battery tied to solar panels.
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