Energy mass balanceCostingEquipment sizingDegradationStorage
Sodium-ion stationary battery storage (containerised): LCOS, round-trip efficiency and degradation
Grid-connected sodium-ion battery containers from 2 to 500 MWh: LCOS in EUR/MWh delivered after the PNNL 2024 method with Keiner et al. 2026 costs, round-trip efficiency, linear capacity fade to 80 % and service life, by reference case.
- CurrencyEUR 2024
- Battery limitinstalled
- 63 documented assumptions
- Updated27 Oct 2026
Mass and energy balance
What the asset draws and delivers for the case and load you choose.
Reference case
Full cycles a year over the usable energy. 365 is the NREL ATB 2025 duty of about one cycle a day. Fewer cycles stretch the cycle-limited life until the calendar life caps it. The slider stops at 340: below, the conservative 2-hour case leaves the sourced LCOS envelope.
Flows
- In: Electricity for charging—
Asset
Sodium-ion stationary battery storage (containerised)
- Out: Electricity discharged—
Annual quantities at the current usage. Band width: share of energy in; non-energy flows are not to scale.
Usable energy of the sodium-ion plant (Keiner et al. convention: per kWh of usable capacity). The catalogue binds products here: Salzstrom SALT BESS 2.3 MWh, Peak Energy Grid Storage 1 at 3.1 MWh. Costs are linear in size; below about 10 MWh the per-kWh cost is an extrapolation of a utility-scale figure and is probably too low (flag shown).
- Rated power
- — MW
- Energy delivered
- — MWh/a
- Energy delivered over the service life
- — MWh
CAPEX
Specific cost at this size, what backs it, and how it behaves with scale.
Specific CAPEX at this size
—
Reference size 100 MWh
Keiner et al. 2026, Table 4 (linear)
Model value: Keiner et al. 2026 energy and power costs at your duration. Customized: your own quote per kWh of usable energy, used as is at every size; the value is then no longer sourced.
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- Ex-factory
- Installed· this figure
- Fully financed
Included
- Equipment
- Installation, civil works and engineering
Not included
- Working capital
- Contingency
Added at project level
- Working capital layer, from the project settings
- Contingency, from the project settings
Project figures
Values passed to project mode when this asset is added to a project.
Sodium-ion stationary battery storage (containerised)Concept sketch, not to scale · drag to rotate
- Electricity for charging in
- —
- Electricity discharged outMain product
- —
- CAPEX to the battery limit
- —
- Fixed O&M
- —
- Variable O&M, excluding feedstocks
- 0 EUR/year
- Asset lifetime
- 12 years
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LCOS excluding charging
A standalone indicator for a quick read. Project mode recomputes it for the whole system.
—
- LCOS: capital—
- LCOS: fixed O&M—
Linked to the balance above
Full cycles a year over the usable energy. 365 is the NREL ATB 2025 duty of about one cycle a day. Fewer cycles stretch the cycle-limited life until the calendar life caps it. The slider stops at 340: below, the conservative 2-hour case leaves the sourced LCOS envelope.
Hours of discharge at rated power. Rated power = usable energy / duration. The power interface cost is per kW, so short durations cost more per kWh.
Average price of the charging electricity, only used in the LCOS including charging. Default: German day-ahead average 2024, 78.51 EUR/MWh (Bundesnetzagentur), a conservative upper reference since storage charges in low-price hours.
Real rate of the capital recovery factor, because all costs are constant 2024 EUR. Default 6.49 %, derived from the PNNL 2024 financing parameters (8 % debt, 13 % equity, 50 % debt, 25.7 % tax, 2.8 % inflation). The slider spans 5.5-6.5 % around that value, the rate at which the cited LCOS envelope holds. A zero rate is handled (CRF = 1/n).
Lowest ambient temperature expected at the site. Compared with the cell working ranges of IRENA 2025 (sodium-ion -40 °C, Li-ion -20 °C). An indicator only: it changes no cost.
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Benchmarks
This model's figures against published references and reference cases.
Round-trip efficiency (AC), %
85 NREL ATB 2025
90 Keiner et al. 2026, §2.3
92 IRENA 2025, Table 2
Reference cases at this size and usage
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All results
Every model output at the current settings, grouped, with the sensitivity charts.
53 outputs · 6 groups · 11 also shown above, dimmed
Levelised cost
7- Capital share of the LCOS
- Computing%
- LCOS with NREL fixed O&M
- ComputingEUR/MWh
- LCOS: charging
- ComputingEUR/MWh
- LCOS including charging
- ComputingEUR/MWh
Size and CAPEX
15- Model CAPEX per kWh (scaled)
- ComputingEUR/kWh
- Model CAPEX per kWh at reference size
- ComputingEUR/kWh
- Cell CAPEX per kWh
- ComputingEUR/kWh
- System periphery CAPEX per kWh
- ComputingEUR/kWh
- Power interface cost
- ComputingEUR/kW
- Power interface CAPEX per kWh
- ComputingEUR/kWh
- Energy share of CAPEX
- Computing%
- Energy-related CAPEX
- ComputingEUR
- Cell CAPEX
- ComputingEUR
- Power-related CAPEX
- ComputingEUR
- CAPEX per kW
- ComputingEUR/kW
- Size extrapolation flag
- Computingflag
Energy balance
9- Energy charged
- ComputingMWh/a
- Charging energy per MWh delivered
- ComputingMWh/MWh
- Discharge full-load hours
- Computingh/a
- Discharge capacity factor
- Computing%
- Average delivered power
- ComputingMW
Degradation and life
11- End-of-life capacity
- Computing%
- Mean capacity retention
- Computing%
- Degradation penalty on energy
- Computing%
- Capacity fade per cycle
- Computing%/cycle
- Cycle life to 80 %
- Computingcycles
- Calendar life
- Computingyears
- Cycle-limited life
- Computingyears
- Service life
- Computingyears
- Cycle-limited life flag
- Computingflag
- Full cycles over the service life
- Computingcycles
- Duty against one cycle a day
- Computing%
Cold climate
3- Margin to the sodium-ion cold limit
- Computing°C
- Within sodium-ion cold range
- Computingflag
- Within Li-ion cold range
- Computingflag
Finance and yearly costs
8- PNNL nominal WACC
- Computing%
- PNNL real WACC
- Computing%
- Capital recovery factor
- Computing1/year
- Annualised CAPEX
- ComputingEUR/year
- Fixed O&M, NREL sensitivity
- ComputingEUR/year
- Yearly cost excluding charging
- ComputingEUR/year
- Yearly charging cost
- ComputingEUR/year
Sensitivities
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Sources
63 documented assumptions · 6 sources
- pnnl.govPNNL, Energy Storage Cost and Performance Assessment — LCOS Workbook v.2024 DocumentationLCOS, CRF and charging cost Eq. 2-4 (p.4-6), replacement at 80 % Eq. 5 (p.7), financing assumptions (p.9)
- publikationen.bibliothek.kit.eduKeiner et al. 2026, Sodium-ion battery cost projections and their impact on the global energy system transition until 2050, J. Energy Storage 146, 119861capex, O&M, lifetime (Table 4), RTE (§2.3), power interface (§3.2)
- irena.orgIRENA (2025), Sodium-ion batteriesa technology brief — efficiency, lifetime, temperature (Table 2), cycle life and costs (p.16)
- atb.nlr.govNREL Annual Technology Baseline 2025, Utility-Scale Battery Storageone cycle a day, RTE 85 %, FOM 4 %
- bundesnetzagentur.deBundesnetzagentur (3 Jan 2025)German day-ahead average 2024, 78.51 EUR/MWh
- ess-news.comESS News (24 Mar 2025)Shanghai sodium-ion procurement ceiling CNY 1.1/Wh — market cross-check
About
Calculator context
About
Calculator context
Containerised sodium-ion battery plant (NFPP or layered-oxide cathode, hard-carbon anode) connected to the grid. You set the usable energy (2 to 500 MWh), the duration (2 to 8 h) and the full cycles a year, and pick a reference case that fixes the round-trip efficiency, calendar life, cycle life to 80 % and power interface cost. The CAPEX follows Keiner et al. 2026 (Journal of Energy Storage 146): an energy-related cost of 116.3 EUR2024 per kWh of usable capacity (75 % cells, 25 % periphery) plus a power interface of 135 EUR/kW, or 400 EUR/kW in the conservative case, the upper end of the 150-400 EUR/kW Keiner cites from other studies. Costs are linear in size: containers are modular and no economy of scale is sourced, so the LCOS does not depend on size. Below about 10 MWh, where the catalogue products sit (Salzstrom SALT BESS 2.3 MWh, Peak Energy Grid Storage 1 at 3.1 MWh), the per-kWh cost is an extrapolation of a utility-scale figure, probably too low, and a flag says so.
Degradation is linear per cycle down to 80 % at the IRENA 2025 cycle life (4,000 to 5,000 cycles). The service life is the shorter of the calendar life and the cycle life divided by the cycles a year (PNNL 2024, Eq. 5); no replacement or augmentation is costed, and calendar fade is not modelled separately because no citable value exists for sodium-ion cells. The levelised cost of storage is a simplified PNNL 2024 LCOS: CAPEX annualised at a real rate over the service life plus a fixed O&M of 1.7 % of CAPEX a year (Keiner), per mean MWh delivered. The headline excludes charging, as Keiner does; a second figure adds the charging price divided by the round-trip efficiency. The default real rate, 6.49 %, is derived from the PNNL financing parameters, not printed by PNNL.
At 100 MWh, 4 h, one cycle a day and the central case, the plant costs 150 EUR/kWh (15.0 MEUR), lasts about 12.3 years (cycle-limited), delivers 32,850 MWh a year on average and gives an LCOS of about 63 EUR/MWh excluding charging, about 150 EUR/MWh with charging at the 2024 German day-ahead average of 78.51 EUR/MWh, a conservative reference since storage charges in low-price hours. The NREL ATB fixed O&M of 4 % is shown as a sensitivity. A cold-climate indicator compares the site minimum temperature with the IRENA cell ranges (-40 °C sodium-ion, -20 °C Li-ion). No revenue, tax or subsidy: those belong to project mode.
Model
109 variables — inputs, calculations and outputs, with their dependencies.
Model
109 variables — inputs, calculations and outputs, with their dependencies.
| Variable | Value | Unit | Depends on |
|---|---|---|---|
| 100 | MWh | — | |
| 4 | h | — | |
| 365 | cycles/year | — | |
| 1 | — | — | |
| 0 | — | — | |
| 150 | EUR/kWh | — | |
| 78.51 | EUR/MWh | — | |
| 6.49 | % | — | |
| -10 | °C | — |
| Variable | Formula | Unit | Depends on |
|---|---|---|---|
if((<=)+(<=)+(<=)+(<)+(>)+(<)+(>)+(<=)+(<)+(<)+(>)+(**(+/(*))>)>,,) | bool | ||
* | kW | ||
* | kWh | ||
* | ratio | ||
if(>=,,) | — | ||
* | ratio |
| Variable | Formula | Unit | Depends on |
|---|---|---|---|
if(==,,if(==,,)) | % | ||
if(==,,) | years | ||
if(==,,if(==,,)) | cycles | ||
if(==,,) | EUR/kW | ||
/max(,) | MW | ||
/max(,) | years | ||
min(,) | years | ||
if(<,,) | flag | ||
(-)/max(,) | %/cycle | ||
* | cycles | ||
-* | % | ||
(+)/ | % | ||
- | % | ||
/(*)* | % | ||
*** | MWh/a | ||
/max(,) | h/a | ||
/* | % | ||
/max(,) | MWh/a | ||
- | MWh/a | ||
/max(,) | MWh/MWh | ||
* | MWh | ||
/ | MW | ||
** | EUR/kWh | ||
- | EUR/kWh | ||
/max(,) | EUR/kWh | ||
++ | EUR/kWh | ||
clamp(*(/)^(-),,) | EUR/kWh | ||
if(>=,,) | EUR/kWh | ||
* | EUR | ||
/max(,)* | % | ||
** | EUR | ||
- | EUR | ||
** | EUR | ||
/max(,) | EUR/kW | ||
if(<,,) | flag | ||
***(-*)+(-*)* | % | ||
((+*)/(+*)-)* | % | ||
if(<,/max(,),(*(+)^)/max((+)^-,)) | 1/year | ||
* | EUR/year | ||
** | EUR/year | ||
** | EUR/year | ||
+ | EUR/year | ||
* | EUR/year | ||
/max(,) | EUR/MWh | ||
/max(,) | EUR/MWh | ||
+ | EUR/MWh | ||
/max(,) | EUR/MWh | ||
+ | EUR/MWh | ||
/max(,)* | % | ||
(+)/max(,) | EUR/MWh | ||
- | °C | ||
if(>=,,) | flag | ||
if(>=,,) | flag |
Assumptions
63 assumptions used in the calculations
Assumptions
63 assumptions used in the calculations
Lower limit in the input guards.
Market range Exact by definition.
0Numerical constantUnit multiplier in the CRF, the guards and the Customized switch.
Market range Exact by definition.
1Numerical constantDivisor of the mean of the beginning-of-life and end-of-life capacity (linear fade).
Market range Exact by definition.
2Numerical constantProtects divisions against a zero denominator.
Market range Exact by definition.
0Numerical constantConverts a percent into a fraction.
Market range Exact by definition.
0.01Numerical constantConverts a fraction into a percent; also the 100 % beginning-of-life capacity.
Market range Exact by definition.
100Numerical constantkWh per MWh.
Market range Exact by definition.
1000Numerical constantkW per MW.
Market range Exact by definition.
1000Numerical constantHours in a non-leap year; feasibility guard and capacity factor.
Market range Exact by definition.
8760Numerical constantDays in a non-leap year; one-cycle-a-day reference duty.
Market range Exact by definition.
365Numerical constantInteger code of the reference case 'Keiner et al. 2026 central case' in the technology_case select.
Market range Identifier only.
1Selector codeInteger code of the reference case 'IRENA 2025 favourable case' in the technology_case select.
Market range Identifier only.
2Selector codeInteger code of the reference case 'Conservative envelope of the cited ranges' in the technology_case select.
Market range Identifier only.
3Selector codeEnergy-related CAPEX of the sodium-ion storage system per kWh of usable energy (cells plus system periphery). It is the same figure in all three reference cases: only the power interface, life and efficiency change between cases.
Market range No independent European range cited in the same boundary; Chinese tenders (1.035 CNY/Wh bid, 1.1 CNY/Wh ceiling) are of the same order but their scope (PCS, EPC) is not stated.
116.3EUR/kWhKeiner et al. 2026, Table 4Splits the energy-related CAPEX into cells and periphery for the breakdown. It changes no total.
Market range No independent split cited.
75%Keiner et al. 2026, §3.2Power interface (inverter / PCS) cost per kW of rated power in the central and favourable cases. Divided by the duration it becomes a per-kWh adder, so short durations cost more per kWh.
Market range135EUR/kWKeiner et al. 2026, §3.2Power interface cost of the conservative case, the upper end of the range cited by Keiner et al.
Market range400EUR/kWKeiner et al. 2026, §3.2Yearly fixed O&M as a share of CAPEX, in all three cases. It contains no augmentation: the capacity fades and the energy delivered falls with it.
Market range 1.7 % (Keiner) to 4 % (NREL ATB 2025, Li-ion, augmentation included).
1.7%Keiner et al. 2026, Table 4Alternative fixed O&M for the sensitivity output 'LCOS with NREL fixed O&M'. It is not used in the headline LCOS.
Market range 1.7 % (Keiner) to 4 % (NREL ATB 2025).
4%NREL ATB 2025Calendar life of the central and favourable cases: the service life is the shorter of this and the cycle life divided by the cycles a year (PNNL Eq. 5).
Market range15yearsKeiner et al. 2026, Table 4Calendar life of the conservative case.
Market range10yearsIRENA 2025, Table 2AC round-trip efficiency of the central case.
Market range 85 % (NREL ATB 2025, Li-ion) to 92 % (IRENA 2025, SIB).
90%Keiner et al. 2026, §2.3Round-trip efficiency of the favourable case.
Market range92%IRENA 2025, Table 2Round-trip efficiency of the conservative case.
Market range85%NREL ATB 2025Full cycles until the usable energy falls to 80 % in the central case.
Market range 4 000-5 000 cycles to 80 % (IRENA 2025, §3.3); IRENA Table 2 gives 500-8 000 across all SIB chemistries.
4500cyclesIRENA 2025, §3.3Cycle life of the conservative case.
Market range 4 000-5 000 cycles to 80 % (IRENA 2025, §3.3).
4000cyclesIRENA 2025, §3.3Cycle life of the favourable case.
Market range 4 000-5 000 cycles to 80 % (IRENA 2025, §3.3).
5000cyclesIRENA 2025, §3.3End-of-life threshold: the linear fade per cycle is (100 - 80) % divided by the cycle life.
Market range 80 % is the usual warranty and PNNL replacement threshold.
80%PNNL LCOS Workbook 2024, Eq. 5Reference duty of one full cycle a day, used for the duty ratio output.
Market range One cycle a day is the usual utility-scale reference.
1cycles/dayNREL ATB 2025Debt rate in the PNNL WACC formula (p.4).
Market range No independent European range cited.
8%PNNL LCOS Workbook 2024, §2.5Cost of equity in the PNNL WACC formula.
Market range No independent European range cited.
13%PNNL LCOS Workbook 2024, §2.5Debt share in the PNNL WACC formula.
Market range No independent European range cited.
50%PNNL LCOS Workbook 2024, §2.5Tax rate of the debt tax shield in the PNNL WACC formula. No other tax is modelled.
Market range No independent European range cited.
25.7%PNNL LCOS Workbook 2024, §2.5Converts the nominal PNNL WACC into the real rate used with constant 2024 EUR.
Market range No independent European range cited.
2.8%PNNL LCOS Workbook 2024, §2.5Lowest working temperature of sodium-ion cells, compared with the site minimum temperature in the cold-climate indicator.
Market range -40 °C (SIB) against -20 °C (Li-ion), IRENA 2025, Table 2.
-40°CIRENA 2025, Table 2Lowest working temperature of Li-ion cells, for the comparison flag only.
Market range -20 °C (Li-ion), IRENA 2025, Table 2.
-20°CIRENA 2025, Table 2Exponent 1: the cost scales linearly with capacity. Containerised battery storage is modular (numbering-up of identical containers) and Keiner et al. give a single per-kWh capex without a size range, so no economy of scale is sourced. Below about 10 MWh this probably underestimates the cost per kWh (fixed project costs are not spread): the calculator flags that range as an extrapolation instead of inventing a scaling law.
Market range No sourced exponent for sodium-ion BESS.
1Keiner et al. 2026, Table 4 (linear)Reference size of the scaling formula. Keiner et al. publish no plant size, so the nominal 100 MWh case is used; with an exponent of 1 it has no effect.
Market range Not applicable.
100MWhAuthoring choiceLower clamp of the scaled specific CAPEX; never reached inside the declared domain.
Market range Model domain 133-316 EUR/kWh.
50EUR/kWhNumerical guardUpper clamp of the scaled specific CAPEX; never reached inside the declared domain.
Market range Model domain 133-316 EUR/kWh.
2000EUR/kWhNumerical guardBelow this size the extrapolation flag is raised: the linear cost model probably underestimates the cost per kWh of a single container.
Market range No sourced threshold.
10MWhAuthoring thresholdUsable energy of the plant. All cycling is 100 % depth of discharge of this usable energy.
Market range100MWhInput defaultRated power = usable energy / duration.
Market range4hInput defaultFull cycles a year at 100 % depth of the usable energy; the usage lever of the page.
Market range365cycles/yearInput defaultReal discount rate of the CRF, because every cost is in constant 2024 EUR with no escalation (no nominal rate is mixed with real costs).
Market range6.49%Input defaultPrice of the charging electricity, only in the LCOS including charging. The headline LCOS excludes it (Keiner convention), so that project mode prices the inlet once.
Market range78.51EUR/MWhInput defaultAC round-trip efficiency chosen by the reference case; not a free input.
Market range90%Reference caseReal WACC derived from the PNNL parameters; the model recomputes it from the five PNNL constants instead of storing it.
Market range No independent European range cited.
6.49%DerivedDocuments the lower end of the literature range for the power interface; the central case uses Keiner's own 135 EUR/kW.
Market range150EUR/kWKeiner et al. 2026, §3.2Upper working temperature of sodium-ion cells; no hot-climate input is modelled.
Market range 80 °C (SIB) against 60 °C (Li-ion).
80°CIRENA 2025, Table 2Cross-check of the cell share only, qualitative: the model's cell cost (75 % of 116.3 = 87.2 EUR2024/kWh) is in EUR 2024 and no conversion is cited, so no position is concluded.
Market range USD 80-105/kWh cells, 2022.
80USD/kWhIRENA 2025Upper end of the IRENA cell cost; qualitative cross-check only.
Market range USD 80-105/kWh cells, 2022.
105USD/kWhIRENA 2025Pack cost lower end; qualitative cross-check only (different currency, year and boundary from the system capex).
Market range USD 90-125/kWh packs, 2022.
90USD/kWhIRENA 2025Pack cost upper end; qualitative cross-check only.
Market range USD 90-125/kWh packs, 2022.
125USD/kWhIRENA 2025Market cross-check only, in CNY: the scope is not stated, so it is not the default and no conversion is made.
Market range Single tender.
1.035CNY/WhSMM 2026Market cross-check only: same order as the model's 133-316 EUR2024/kWh, but in USD 2025 with an unknown scope, so no position is concluded.
Market range Single tender.
150USD/kWhESS News 2025LCOS = (CAPEX x CRF + fixed O&M) / mean yearly energy delivered (Keiner convention, charging excluded); the version with charging adds the charging price divided by the round-trip efficiency (PNNL ECC term). CRF over the service life = min(calendar life, cycle life / cycles a year) (PNNL Eq. 5).
Market range Not applicable.
—MethodAll costs in constant 2024 EUR, no escalation, discounted at a real rate. The yearly O&M exported to project mode is undiscounted and does not depend on the discount rate.
Market range Not applicable.
—ScopeNo cell replacement and no augmentation: the service life ends when the usable energy reaches 80 % or at calendar life, whichever comes first. Project mode replaces the whole asset at that life.
Market range Not applicable.
—ScopeCapacity fade is linear per cycle only. Calendar ageing is not modelled separately: it only caps the life. When the life is calendar-limited, the end-of-life capacity is therefore above 80 %, which is optimistic.
Market range No independent range cited.
—LimitationCosts are linear in size, so the LCOS does not depend on size. Below about 10 MWh the per-kWh cost is probably underestimated: the calculator raises the extrapolation flag instead of inventing a scaling law.
Market range No sourced scaling law.
—LimitationThe CAPEX is read as an installed system cost (cells, periphery, power interface). It is exported as 'installed': project mode adds only its working-capital layer and contingency (about x1.17 with the defaults), not engineering or site layers.
Market range Not applicable.
—ScopeOver the corners of the slider box the LCOS excluding charging stays within about 49-159 EUR/MWh, the CAPEX within 130-316 EUR/kWh, the end-of-life capacity within 80-83 % and the energy delivered within about 610-166,000 MWh a year. The slider box is deliberately narrow on cycles and discount rate so that every corner stays inside the sourced envelope; outside it the conservative 2-hour case would exceed it.
Market range Not applicable.
—Bounds