In 2025, the global average price of a turnkey battery energy storage system (BESS) is US$117/kWh, according to the Energy Storage Systems Cost Survey 2025 from BloombergNEF (BNEF), published last week (10 December). That was a 31% decline from 2024 numbers. Department of Energy's (DOE) Energy Storage Grand Challenge is a comprehensive program that seeks to accelerate. By 2035, BNEF forecasts LCOE reductions of 30% in solar, 25% in battery storage, 23% in onshore wind and 20% in offshore wind. BNEF's data shows that the global benchmark cost for a four-hour battery project fell 27% year-on-year to $78 per megawatt-hour (MWh) in 2025 – a record low since BNEF. Ember provides the latest capex and Levelised Cost of Storage (LCOS) for large, long-duration utility-scale Battery Energy Storage Systems (BESS) across global markets outside China and the US, based on recent auction results and expert interviews. The main cost drivers are the type of chemistry, the system size, balance-of-system components, installation, and local permitting. The dominant technology today is lithium-ion batteries, especially LFP.