How battery and storage TCO is modelled
A battery system's cost is not its purchase price. Cycle life, augmentation, efficiency losses and end-of-life handling usually decide the ten-year number.
Cost lines in a storage model
| Line | What it covers |
|---|---|
| Capital | Cells or racks, BMS, enclosure, thermal management, PCS where included, and balance of system. |
| Installation | Civil works, electrical connection, commissioning and protection settings. |
| Operation | Monitoring, spares, insurance and scheduled maintenance. |
| Degradation | Capacity fade against the stated cycling duty and any augmentation or replacement event, with its year and cost. |
| End of life | Removal, transport and treatment obligations where the destination imposes them. |
What stays open until confirmed
Cycle life and warranty terms are supplier claims until the datasheet and warranty document are in hand. Round-trip efficiency, auxiliary load and the actual duty cycle are frequently scenario values rather than measured data for the buyer's site.
Worked example
The 10 MWh data-centre storage study sets out a ten-year analysis with its assumptions, cash flows and exclusions stated on the page. Read its own source rows before reusing any figure.
What this model does not tell you
It does not tell you the cycle life you will actually achieve, the warranty you will actually receive, or the value of resilience to your operation. Those depend on the site, the duty cycle and the contract.
How this differs from the other classes
Storage is the only class here where the asset degrades against a duty cycle you choose. That makes the operating assumption, not the purchase price, the variable that most often decides the ten-year result.
Questions to put to a supplier
- What usable capacity is guaranteed at beginning of life, and at what end-of-life threshold does the warranty stop applying?
- What cycle life is warranted, at what depth of discharge, temperature and C-rate?
- Is augmentation included in the price or the warranty, and at which year is it assumed?
- What round-trip efficiency is stated, and at what charge and discharge rate?
- Which transport and safety documents accompany the shipment, and at which revision?
The input most often left unverified
The duty cycle. Datasheet cycle life is quoted against a laboratory profile; the value that governs the real result is how the system is actually charged and discharged on site. Until that profile is written down, any degradation figure applied to it is an assumption.