Global Benchmark Cost For 4-Hr BESS Project Fell 27% YoY To $78/MWh in 2025: Study

BloombergNEF (BNEF) recent research confirms  a drop in global benchmark cost for a four-hour battery project by 27% year-on-year (YoY) to $78 per megawatt-hour (MWh) in 2025 — the lowest level since BNEF began tracking costs in 2009.

In a press release reflecting on clean power costs in 2025, BNEF’s latest Levelized Cost of Electricity 2026 report points to mixed signals across technologies. While battery storage project costs plunged to new lows last year, most other clean power technologies became more expensive, according to the report.

BNEF’s global benchmark costs for solar, onshore wind, and offshore wind all increased in 2025, reversing the downward trend of recent years. The rise was driven by a combination of supply chain constraints, weaker resource availability, and market reforms in mainland China.

“Cheaper costs due to manufacturing overcapacity from the electric vehicle market and better system designs are transforming the economics for large energy storage projects,” said Amar Vasdev, lead author of the report and senior energy economics associate at BloombergNEF. “The levelized cost of electricity for a four-hour system is now below $100/MWh in six markets. As costs continue to drop, we expect battery storage to strengthen solar project revenues, support broader renewable deployment, and accelerate the shift toward storage‑led system balancing over fossil-fuel‑based peaking capacity.”

BNEF forecasts Solar LCOE to Reduce 30%, BESS 25%By 2035 

Despite rising global protectionism, supply-chain challenges, and higher financing costs, BNEF expects innovation and competition to continue driving declines in clean-energy technology costs. It forecasts levelized cost of electricity (LCOE) reductions of 30% for solar, 25% for battery storage, 23% for onshore wind, and 20% for offshore wind by 2035.

Lower battery pack prices, intensifying competition among manufacturers, and improved system designs have all contributed to the rapid cost declines. Falling battery costs are also accelerating the build-out of co-located renewable projects. The research noted that developers added 87 GW of combined solar and storage capacity in 2025, delivering power at an average cost of $57/MWh. By contrast, the benchmark cost of a typical fixed-axis solar farm rose 6% in 2025 to $39/MWh, while onshore wind reached $40/MWh and offshore wind climbed to $100/MWh globally.

The report hinted that a challenge in fossil fuel supply can turn into an opportunity in areas like gas-turbine supply chains and grid-connection queues for quick-to-deploy clean power technologies. This is especially possible as co-located solar and four-hour battery systems are capable of meeting a substantial share of data-center electricity demand at a lower cost than gas.

Their competitiveness is improving in regions such as California and parts of Texas as solar output expands and storage prices fall. Together, these trends underscore how rising gas costs and rapid advances in clean-energy technologies are positioning renewables as the most cost-effective sources of firm and flexible power.

Wind Energy To Overtake Gas As Cheap Electricity Option

Tight offshore-wind supply chains pushed costs higher in nearly all major markets and up 12% globally. In the UK in particular, the cost of recently financed offshore wind projects now sits 69% higher than five years ago, with BNEF expecting costs to remain elevated until at least 2030. 

On the contaray wind power in the US has regained its position as the cheapest option for new electricity generation, overtaking gas-fired power generation for the first time since 2023. Recent surges in gas turbine demand, driven heavily by data‑center expansion, have doubled US turbine capex in just two years and pushed combined‑cycle gas turbine costs to record levels, far above global averages.

With wind project costs continuing to diverge regionally, mainland China retains a cost advantage. On the contrary, onshore wind projects outside mainland China saw a 4% cost decline in 2025. Yet the global benchmark rose by 2%, pushed up by recent Chinese projects built in areas with lower wind speeds, which lifts costs.