LCOS Calculator: Levelized Cost of Storage per kWh
LCOS — the levelized cost of storage — is to storage what LCOE is to generation: the single all-in cost to store and re-deliver one kilowatt-hour of electricity across a battery project's entire life. It rolls upfront capital, the electricity you buy to charge the battery, round-trip efficiency losses, operating costs, capacity degradation, and augmentation (adding cells over time to offset fade) into one discounted cost per kWh delivered. That's why LCOS captures things generation LCOE simply doesn't. A battery isn't a power plant — it consumes electricity to create electricity, so the price of the energy you charge with is a real cost. Round-trip efficiency means you always get back less than you put in. And lithium-ion cells fade, so either output falls year over year or you spend capital to augment the system. LCOS puts all of that on one footing. Most importantly, LCOS is what determines whether a storage project actually pencils out. A battery's revenue — energy arbitrage spreads, capacity market payments, ancillary services, demand charge reduction — has to beat its LCOS for the project to create value. Compare LCOS against the revenue per kWh you expect to capture; if revenue exceeds LCOS, the project earns a positive return.
A 4-hour 25 MW system = 100 MWh. Utility-scale LFP typical.
All-in EPC cost for utility-scale 4-hour LFP: ~$300–400/kWh.
1 cycle/day ≈ 365. Arbitrage-heavy: 300–365. Capacity-only: 50–100.
The power you buy to charge. Off-peak/curtailed solar: $10–40/MWh.
Typical utility-scale BESS: ~$4–8/kWh-yr (i.e. $4,000–8,000/MWh-yr).
Utility-scale LCOS typically modeled over 20 years. LFP warranty 10–15 years / 6,000+ cycles.
levelized cost of storage
$0.19/kWh delivered
30,800 MWh/yr at 88% RTE × 350 cycles
$35M total capital
share of total LCOS
Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.
How we calculate this →How LCOS is calculated: discounted lifetime cost per kWh delivered
LCOS uses the same discounted cash-flow framework as LCOE, but adapted for the economics of a storage asset — which buys electricity, stores it, and sells it back, losing energy to round-trip inefficiency along the way.
The first step converts capital cost to a total: $/kWh × usable capacity (MWh) × 1,000. For a 100 MWh system at $350/kWh, that's $35 million upfront. This is paid at the start and is not discounted.
For each year t from 1 to the project lifetime, the calculation tracks delivered energy and annual costs. Effective capacity fades each year, but augmentation offsets most of that fade: net degradation = max(0, degradation − augmentation × 1.67), because augmentation spending goes to cells (roughly 60% of total capital), so each dollar of augmentation replaces about 1.67× its rate in capacity fade. Cumulative capacity loss is also capped at 10%, so when augmentation is active delivered energy is held close to flat rather than falling year over year. Effective capacity in year t = usable capacity × max(0.90, (1 − net degradation)^(t−1)). Energy delivered in year t equals effective capacity × round-trip efficiency × cycles per year — you only get back the RTE fraction of what you charge, and only on the cycles you actually run. The electricity you must buy to charge is the inverse: (effective capacity × cycles) ÷ RTE, because round-trip losses mean you buy more than you deliver. Charging cost is that energy times the charging electricity price.
Annual O&M is $/kWh-year × capacity (MWh) × 1,000. Augmentation — the capital spent adding cells to offset fade — is modeled as a fixed percentage of total capital each year. Because that same augmentation is what holds delivered energy close to flat (via the net-degradation offset above), the model avoids the double-counting error of letting output fall to fade while also paying to replace it. Total annual cost (charging + O&M + augmentation) and delivered energy are both discounted to present value by dividing by (1 + discount rate)^t.
LCOS = (total capital + sum of discounted annual costs) ÷ (sum of discounted annual energy delivered). The result is $/MWh — divide by 1,000 for $/kWh or multiply by 100 for cents/kWh.
The cost breakdown shows what's driving your LCOS. Capital usually dominates for a 4-hour system (often 50–70%), but charging energy cost rises sharply with cycle frequency and the price of charging power — a battery cycled daily on expensive peak power can see charging become the largest single component. Augmentation and O&M are smaller but persistent. The discount rate matters too: because most storage cost is upfront, cheaper financing meaningfully lowers LCOS.