The BESS Cost Curve: Why Storage Economics Just Crossed the Bankability Line
By Sudarshan Karweer
Battery energy storage has quietly crossed the line from pilot to portfolio. LFP cell indices near $46/kWh and container CAPEX around $66/kWh have compressed the levelised cost of storage to a point where capacity plus availability revenue stacks now clear lender DSCR thresholds.
The analytical nuance is duration. Multi-hour systems are sized not by peak MW but by the revenue their MWh can address — ancillary services, ToD arbitrage and firming for RTC/FDRE contracts. The right sizing logic, augmentation plan and degradation curve determine whether a project is bankable or merely buildable.
For investors and developers: the alpha is no longer in owning storage — it is in structuring it. Contract design, warranty stacking and augmentation reserves separate a 10% IRR from an 18% one.
