What is levelized cost of storage (LCOS) and how is it used?

• A. It's the cost of building a storage facility per year.
• B. LCOS is the cost per unit of stored energy over a storage asset's lifetime; used to compare storage technologies and projects.
• C. It's the operational cost only.
• D. Cost per kWh of installed power.

Answer: (B)

Levelized cost of storage measures the cost per unit of stored energy over the entire lifetime of a storage asset. It combines capital costs, operation and maintenance, replacements, and efficiency losses (charging/discharging inefficiencies and degradation) and spreads them over the total amount of energy the storage can deliver. This makes the metric comparable across different storage technologies and project sizes, since it converts all those varied costs into a single, common unit like $/kWh.

Because of that, LCOS is used to compare how different storage options perform economically: you can weigh upfront investment against how much usable energy you expect to retrieve over the asset’s life, and adjust for factors like asset lifetime and discount rate. It’s not just the annual building cost or just the operational cost, and it isn’t simply the cost per installed power capacity. Rather, it’s a per-energy metric that helps determine whether storage is cost-effective in a given application and how different technologies stack up against one another.