In 2025, the world installed more than 100 gigawatts of battery storage connected to the power grid — for the very first time. That's enough clean energy storage capacity to power tens of millions of homes, all hooked up in just one year. The milestone comes from a brand-new report by Wood Mackenzie, an energy research firm that just published its first-ever ranking of the biggest battery integrators — the companies that build the systems combining batteries, power controls, and cooling into ready-to-use storage units.
The ranking reveals a global industry where Chinese companies are currently leading the pack. Six of the top ten integrators are based in China, including five of the top six spots. At the very top sits Sungrow, a company that surprised many analysts who expected household names like Tesla or BYD to claim the number-one spot. Tesla, China's CATL, and BYD still made the top five, joined by Fluence — a joint venture involving American companies — and South Korean electronics giant LG. Finland's Wärtsilä also cracked the top ten.
What's driving their success? Wood Mackenzie's analysts identified three things that set the leaders apart. First, experience: six of the top ten have been integrating batteries for more than a decade. Second, control: every company on the list makes at least one critical piece of the system itself — like battery cells or power converters — which helps them build better products and avoid supply chain headaches. Third, investment: eight of the top ten outperformed benchmarks for how efficiently their systems run, and nine poured more than 4 percent of their revenue into research and development during 2025. Nearly all of them — nine out of ten — reported making a profit.
The race isn't over, though. "The next phase of competition will be determined less by manufacturing scale alone and more by the ability to execute consistently across global markets," said Timothy Shen, a senior research analyst at Wood Mackenzie. As countries set new rules about where products are made, how projects are financed, and what technical standards they must meet, the companies that can adapt while keeping quality high may pull ahead.
For the planet, this growth is good news. Bigger, better battery systems mean grids can store more energy from solar panels and wind turbines — energy that would otherwise go to waste. That makes clean power more reliable and helps the world move away from fossil fuels faster.