Still sizing storage like it’s 2021? That’s the grid equivalent of buying a sports car and never shifting out of second. Cheaper battery energy storage systems (BESS) just changed the game for 6-8 hour projects, and the ripple effects are landing in utility planning rooms, developer spreadsheets, and data center design reviews.

The problem

For years, the default was 2-4 hour lithium projects. Anything longer looked pricey, risky, or both. Utilities struggled to firm solar into the evening peak without leaning on gas peakers. Developers fought interconnection queues while BOS costs ate margins. Data centers stacked diesel because batteries couldn’t pencil past a few hours. In short: longer-duration storage needed a cost reset.

The solution

Turnkey BESS prices just delivered that reset. Multiple trackers show a drop on the order of 30-40% year-over-year, with BloombergNEF’s latest benchmark putting global turnkey systems at roughly $165/kWh in 2024, the steepest annual fall since the survey began, as noted in this study. Battery pack prices are also sliding: BNEF reports global average packs at $108/kWh in 2025, with stationary storage packs among the lowest-price segments, as noted in this study and this study. Costs are falling fastest where projects use energy-dense containers, larger-format LFP cells, and streamlined supply chains.

The evidence (minus the lab coat)

• Global turnkey BESS dropped to about $165/kWh in 2024, a roughly 40% year-over-year fall, as noted in this study.
• Pack prices hit $108/kWh globally in 2025, with LFP leading the cost-down and stationary storage as the lowest-price segment, as noted in this study and this study.
• NREL’s 2024 ATB shows continued CAPEX declines and improving economics for utility-scale storage across durations, especially as component costs compress, as noted in this study.
• US deployments and duration needs are rising quickly, setting the stage for more 6-8 hour projects to firm renewables and replace peakers, as noted in this study.

What cheaper BESS means for 6-8 hour projects

• Longer-duration finally pencils: Lower $/kWh pulls levelized cost of storage down for 6-8 hour systems, strengthening energy-shifting, capacity, and ancillary services revenue stacks.
• More LFP, fewer compromises: LFP remains the default for utility-scale safety and cost, backed by larger-format cells and higher-density containers that further cut delivered $/kWh, as noted in this study.
• Data centers get real options: 6-8 hour BESS can displace diesel for outage coverage and peak shaving, with stackable grid services for uptime-first designs.
• Siting flexibility improves: Better cost per kWh lets developers absorb tougher sites, higher BOS, and augmentation plans without breaking economics.

Sodium-ion’s 2026 moment

Lithium still dominates, but sodium-ion is moving from pilot to plan for stationary storage. Early US grid deployments are underway, with OEMs and integrators signaling multi-hundred MWh pipelines and hyperscaler interest, as noted in this study. As LFP prices fall, sodium-ion’s pitch leans on safety, thermal stability, and domestic-friendly supply chains. If sodium reaches cost parity with LFP, it could become a go-to for indoor or large-scale 6-8 hour projects that prize resilience over extreme energy density, as noted in this study and contextualized by broader cost trends in this study.

Procurement tactics for 2026 builds

• Lock EPC and BOS, keep chemistry flexible: Use performance-based specs so you can ride further price drops and choose between high-density LFP or sodium-ion without redesigning the plant.
• Model 6-8 hour stacks with real cycles: Align warranty, augmentation, and dispatch on capacity payments plus arbitrage and ancillary services.
• Safe harbor smartly: Coordinate ITC timing and domestic content strategies while tracking OEM lead times. US policy remains supportive of standalone storage, as noted in this study.
• Design for augmentation: Lower pack pricing enables staged energy additions that maintain nameplate over 15-20 years without sticker shock.

Developer and utility checklist

• Re-run LCOS for 6-8 hour durations using updated turnkey and pack price benchmarks.
• Compare LFP vs sodium-ion on safety, temperature profile, footprint, and augmentation strategy.
• Prioritize containers that hit higher MWh per footprint and reduce BOS complexity.
• Structure offtake for revenue stacking: capacity, ancillary services, and energy shifting.
• Stress-test interconnection and construction schedules against 2025-2026 module lead times.

The bottom line

Global battery storage prices have fallen nearly a third year-over-year (and even more in some trackers), and that drop unlocks 6-8 hour BESS at scale. Expect LFP to dominate near term and sodium-ion to earn real ground by 2026, especially in safety-first, cost-sensitive stationary projects. Cheaper energy per kWh doesn’t just cut capex. It expands what storage can do for the grid, developers, and data centers alike.