Mitsubishi Estate starts a 230 MWh battery as Japan chases China on cells

Mitsubishi Estate starts a 230 MWh battery as Japan chases China on cells Japan's developers are pairing storage with renewable plants for corporate buyers, but the cells come from a Chinese industry that builds most of the world's lithium-ion batteries. Mitsubishi Estate has begun building a 67 MW / 230 MWh battery storage facility in Chikuzen, in Japan's Fukuoka prefecture, with commercial operations scheduled for 2028, Japan NRG reported on Monday (2026-06-08).⁶ That matters because Japan is bolting batteries onto a renewables fleet built largely on fixed subsidies, and the storage is what turns intermittent solar into something corporate buyers can actually rely on. Many of those buyers have signed up to RE100, the global initiative under which firms pledge to source 100% of their electricity from renewables.⁶ A smaller project in the same report showed the mechanism. Green Growth and Rising Next began converting an existing 2.5 MW solar plant in Fukuoka from the feed-in tariff to the feed-in premium, adding a 1.99 MW / 8.1 MWh battery, with operations targeted for spring 2027.⁶ Moving from a fixed tariff to a market-referenced premium strips out the guaranteed price and rewards developers who can store cheap midday solar and sell it when the grid is short.⁶ The constraint sits upstream. China holds roughly 80% of global lithium-ion battery production capacity for EVs, and Japanese cell makers are competing against rivals whose production lines are more automated and more tightly integrated, Japan NRG said.⁶ One Japanese answer is a compact battery-making plant designed to cut the coordination penalty of building a conventional factory, a model that could reduce total costs by 70%, the report said.⁶ Whether that closes the gap is unproven. The figure is a target, not a result, and it is being chased against an incumbent that already supplies most of the world's cells.⁶ China's manufacturing scale is the by-product of an energy build-out without modern precedent. Its clean-tech expertise, from better electricity markets to long transmission lines and the engineering that makes renewables useful, is increasingly sellable beyond its borders, the Economist has argued.³ That build-out is not clean in any simple sense: China leads the world in renewable expansion while its coal projects keep booming, what Ember's Muyi Yang called a "build before breaking" approach, AFP reported.⁴ Even so, coal generation in China and India fell in 2025 for the first time in 52 years, Carbon Brief found, after each added record clean capacity.⁵ The longer trend is set even if the pace is not. The IEA expects renewables and nuclear to reach half the world's power mix by the end of the decade, with renewable output growing about 1,000 TWh a year through 2030 and solar alone adding more than 600 TWh, its Electricity 2026 report said.¹ Coal still supplies roughly 35% of global electricity.² For Japan, the pull is as much corporate as regulatory. RE100 members need verifiable renewable supply, and on a grid with scarce land and pronounced midday solar peaks, that increasingly means paired storage rather than panels alone.⁶ The Mitsubishi Estate and Green Growth projects are early instances of a model the market expects to repeat.⁶ The open question is whether Japan's storage buildout deepens its reliance on Chinese cells or seeds a domestic industry that can compete on cost. Watch the commissioning dates: spring 2027 for the Fukuoka conversion, 2028 for Chikuzen, and whether the 70% cost-cut factory model moves from claim to running line.⁶