Vanadium redox flow battery (VRFB) storage plant

Protects divisions.

Market range Not applicable.

Unit term in the CRF, the markup cascade and the guards.

Market range Exact by definition.

Turns a percent (0-100) into a fraction.

Market range Exact conversion, no range.

Turns a fraction into a percent for display and for the guards.

Market range Exact conversion, no range.

PNNL quotes power-related costs per kW; the inputs are in MW.

Market range Exact conversion, no range.

PNNL quotes energy-related costs per kWh; the energy input is in MWh.

Market range Exact conversion, no range.

Converts annual energy to an average power for the hourly flows and the capacity factor.

Market range Exact for a 365-day year.

Select value of the PNNL baseline case.

Select value of the default case, which reproduces the earlier default inputs.

Select value of the developer-performance case.

Hours available per day for charge, discharge and rest.

Market range Exact.

Exponent that turns a one-way converter efficiency into its round-trip loss.

Market range Exact (one pass in, one pass out).

Number of rest periods counted in the daily cycle time.

Market range Exact by the equation.

Durations below 6 h take the 4 h rest value (0.5 h); 6 h and above take zero. The 2 h value (1.0 h) is outside the model domain (4-12 h). Over 4-12 h the rest term never binds the cycle count, so the step changes no result.

Market range PNNL tabulates only 2, 4 and 6+ h; values between columns are not printed.

Lowest duration (energy / power) the calculator accepts. Below 4 h the installed CAPEX per kWh leaves the PNNL battery band and the bounds no longer hold.

Market range PNNL costs VRFB at 2, 4, 6, 8, 10 and 24 h; the calculator keeps 4-12 h.

Highest duration the calculator accepts. Above 12 h the LCOS keeps rising (time-limited throughput) and the bounds were not checked there.

Market range No independent range cited for the upper limit; it is a modelling choice.

Lowest rated power accepted, the low end of PNNL's size rule (+5 % at 1 MW).

Market range PNNL 2020 prices 1, 10 and 100 MW systems.

Highest rated power accepted, the high end of PNNL's size rule (-5 % at 100 MW).

Market range PNNL 2022 prints systems up to 1,000 MW; the calculator stops at 100 MW.

Converts every 2021 USD cost to constant EUR 2021. All money in the calculator is EUR 2021.

Market range Single official annual average; no range.

Power-related part of the DC storage block: stacks, pumps and piping, paid per kW. Also the cost of the year-12 stack replacement.

Market range No independent range cited for the power part alone.

Energy-related part of the DC storage block: electrolyte and tanks, paid per kWh. Never replaced over the project life.

Market range PNNL-33283 Sec. 4.3.1 prices the electrolyte alone at 105-150 USD/kWh depending on chemistry.

DC balance of system (racking, containers, DC wiring) as a share of the storage block.

Market range Single PNNL value; no independent range cited.

Power equipment: DC-DC converter between stacks and inverter.

Market range Single PNNL value for 2021.

Power equipment: bidirectional inverter (power conversion system).

Market range Single PNNL value for 2021.

Power equipment: energy management system and controls.

Market range Single PNNL value for 2021.

Transformer, switchgear and grid connection, paid per kW and not marked up.

Market range Single PNNL value for 2021.

System integration markup on the direct cost (storage block + DC BOS + power equipment).

Market range Single PNNL convention.

Engineering, procurement and construction markup.

Market range Single PNNL convention.

Project development markup (permitting, interconnection studies, developer margin).

Market range Single PNNL convention.

Published all-in cost used to check the CAPEX cascade at a configuration other than the 10 MW reference.

Market range Single printed figure.

PNNL size rule, the source of the CAPEX scale exponent.

Market range +5 % at 1 MW, -5 % at 100 MW in PNNL 2020.

Exponent of the CAPEX scale law on energy capacity, a power-law fit of PNNL's +/-5 % per decade size rule. Applied on the energy capacity at fixed duration, it scales power and energy together, as PNNL's factor does for 'power and energy content'.

Market range +5 % at 1 MW, -5 % at 100 MW (PNNL).

Reference size of the scale law: the 10 MW / 4 h configuration of the cited cost anchor, where the size factor is 1.

Market band for installed battery storage cost, all technologies and sizes.

Market range USD 300-600/kWh (2021).

Upper edge of the installed-cost band.

Market range USD 300-600/kWh (2021).

DC round trip of the two PNNL cases, the starting point of the AC chain.

Market range 71 % (PNNL) to 78-82 % (developer values with auxiliaries).

Upper end of the developer range quoted by PNNL; documented, not used by any case.

DC round trip of the developer case.

One-way inverter efficiency, crossed twice per cycle.

Market range Single PNNL value.

One-way transformer efficiency, crossed twice per cycle.

Market range Single PNNL value.

Published AC round trip, kept only as a reference for rte_ac_gap_vs_pnnl_table_pct_points.

Market range 65 % (PNNL 2021).

Literature AC round-trip range for RFBs.

Upper edge of the literature RTE range.

Warranty-style cap on annual equivalent full cycles.

Market range Single PNNL value for all technologies.

Depth of discharge per cycle; sets the discharge time per cycle and the 1/DOD cap.

Market range Single PNNL baseline.

Rest after each charge and each discharge for short-duration RFBs.

Market range 1.00 h at 2 h, 0.50 h at 4 h, 0 at 6 h+.

No rest is required for long-duration RFBs.

Market range Zero by the table.

Stack and pump life; the replacement is paid at the stack power cost.

Market range Single PNNL value.

Operating life over which replacements and the residual value are placed. Also the asset lifetime handed to project mode.

Market range Single PNNL value for VRFB.

Construction period, documented to explain the gap with PNNL's LCOS.

Market range Single PNNL value.

Annuity period of the capital recovery factor.

Market range Single PNNL value.

Default real discount rate for the CRF, the stack replacement and the residual value.

Market range Real interest 5.06 % to real cost of equity 9.92 %.

Lowest real rate in the input box.

Market range PNNL real rates 5.06-9.92 %.

Highest real rate in the input box.

Market range PNNL real rates 5.06-9.92 %.

Published all-in fixed O&M at the reference configuration.

Market range Single printed value.

Routine share of fixed O&M, documented to show why it is not used alone.

Market range Single PNNL value.

All-in fixed O&M rate (routine O&M plus power-equipment augmentation, as PNNL's 'final' figure) on the direct CAPEX. Augmentation is not added again on top.

Market range 0.43 % routine only (PNNL); no independent range cited for the all-in rate.

Documented component of PNNL's final fixed O&M.

Market range Single PNNL value.

Augmentation interval inside PNNL's fixed O&M.

Market range Single PNNL value.

Annual warranty cost used in every reference case (low end of PNNL's range): a model value, no longer an input.

Market range USD 1.25-2.59/kWh-yr.

High end of the annual warranty cost.

Market range USD 1.25-2.59/kWh-yr.

Variable O&M per MWh discharged.

Market range Single PNNL generic value.

PNNL's reference charging price.

Market range Single PNNL value; the slider runs 20-100 EUR/MWh.

Electrolyte value basis for the end-of-life buy-back.

Market range USD 105/kWh (mixed acid) to 150 (sulfuric) to 180 (standard grade).

Alternative electrolyte price.

Market range USD 105-180/kWh across chemistries.

Electrolyte residual of the PNNL baseline case: none credited to the owner.

Electrolyte buy-back share at year 24 in the two buy-back cases.

Upper end of the vendor claim; documented, not used by any case.

PNNL's end-of-life sensitivity, documented to frame the residual-value choice.

Market range Single PNNL sensitivity value.

Low end of a PNNL multi-technology LCOS range at 100-1,000 MW, kept as context; the LCOS bound is derived from the model's input-box enumeration instead.

Market range USD 0.13-0.20/kWh for gravitational, thermal, Li-ion LFP, vanadium RFB and Li-ion NMC at 100-1,000 MW, after tax.

High end of PNNL's printed battery LCOS at 1-10 MW, kept as context; the LCOS bound is derived from the model's input-box enumeration instead.

Market range USD 0.20-0.40/kWh for all battery systems at 1-10 MW, durations up to 10 h, after tax.

ECONOMIC BASIS. Every cost is in constant EUR 2021: USD 2021 figures are divided by 1.1827 USD/EUR and nothing is escalated (O&M, warranty, charging price and the year-12 stack replacement are all at today's real cost). The only rate is REAL (default 6.52 %, PNNL real WACC), used for the CRF, the stack replacement and the electrolyte residual. There is no nominal rate and no inflation input. The discount rate never enters a line handed to project mode as opex: fixed O&M, warranty and variable O&M are undiscounted annual cash. The iron flow battery of the same batch uses the same basis.

Market range Not applicable.

CAPEX. Storage block = 351.5 USD/kW x kW + 177.7 USD/kWh x kWh; DC BOS = 20 % of it; power equipment = 60 + 73 + 7.8 USD/kW; direct = sum; SI, EPC and PD are 15 % each on the running total (x 1.520875); grid integration 25 USD/kW is added after the markups; the total is divided by 1.1827. That build-up is PNNL's 10 MW anchor. SIZE: it is multiplied by (energy / 40 MWh)^(0.978 - 1), the power law of PNNL's +/-5 % size rule (x1.052 at 1 MW, x0.951 at 100 MW at 4 h). The 100 MW / 10 h cross-check gives 384.2 USD/kWh against PNNL's printed 385 (0.998); it was 412.3 (1.071) without the rule. CUSTOMIZED: the user's EUR/kWh replaces the model value at every size, no scale law; O&M, warranty and the stack replacement stay on the model's sourced build-up at the plant size (size factor applied), because a quote does not reveal its direct-cost split. The power/energy split is the model split times the ratio of the retained CAPEX to the model CAPEX before the size factor, so power part x kW + energy part x kWh = total CAPEX in both modes.

Market range PNNL battery band USD 300-600/kWh; model 336-460 EUR/kWh over 4-12 h.

ROUND TRIP. AC round trip = DC round trip including pumping and auxiliaries x inverter efficiency^2 x transformer efficiency^2 = 0.71 x 0.98^2 x 0.98^2 = 65.49 % by default. It is derived from components and never set to a published value; the published 65 % is shown separately as a gap. Over the DC input 71-82 % it spans 65.49-75.63 %, inside the 65-80 % literature range.

Market range 65-80 % for RFBs (PNNL 2020 literature range).

CYCLES. Discharge time = DOD x duration, charge time = discharge time / AC round trip, rest = 0.5 h below 6 h and 0 from 6 h (two rests per cycle). Cycles = min(requested equivalent cycles / DOD, 8,760 / cycle time): PNNL Eq. 2 with the user's equivalent cycles in place of PNNL's fixed 365 (default 365, slider 285-365). DOD 80 %. At 365 the request binds up to about 9.5 h; above, the plant is time-limited (346.7 equivalent cycles at 10 h, 288.9 at 12 h) and the annual discharge stays at 8,760 x P / (1 + 1/RTE). At 10 MW the LCOS is lowest near 9.5 h (133.3 EUR/MWh at the defaults) and rises to 151.3 at 12 h.

Market range Not applicable.

LIFECYCLE. Stacks and pumps are replaced once, at year 12, at 351.5 USD/kW times the size factor (no markups, no learning; Customized does not change it); its annualised cost is its own LCOS component, because project mode only replaces the whole asset. Electrolyte and tanks are never replaced. At year 24 the electrolyte is credited at the residual share of 105 USD/kWh (mixed-acid electrolyte) set by the reference case: 0 % in the PNNL baseline (the developer takes the electrolyte at no cost), 30 % in the buy-back cases (VRB Energy lease claim, vendor-side, evidence low). PNNL treats a net disposal COST of 36.5 USD/kWh as a sensitivity. CAPEX_PV = CAPEX + replacement / (1+r)^12 - residual / (1+r)^24, annualised with CRF over 20 years.

Market range Not applicable.

O&M. Fixed O&M = 0.47 % of direct CAPEX times the size factor (Customized does not change it), the rate that reproduces PNNL's 'final' fixed O&M (6.66 USD/kW-yr, which PNNL describes as 0.43 % routine plus power-equipment augmentation of 30 % every 10 years). PNNL's decomposition cannot be rebuilt from its text: 0.43 % alone gives 6.09 (0.914x) and 0.43 % plus augmentation levelised at the real WACC gives 9.21 (1.38x). Augmentation is therefore NOT modelled separately, or it would be counted twice. Warranty: 1.25 USD/kWh-yr x kWh, every year, in every reference case (low end of PNNL's USD 1.25-2.59/kWh-yr). Variable O&M: 0.5125 USD/MWh discharged, 2020 USD unescalated, under 0.1 % of LCOS.

Market range Fixed O&M 0.43 % routine (PNNL); warranty USD 1.25-2.59/kWh-yr.

CONVERGENCE. This calculator is PRE-TAX: PNNL's Eq. 1 with a plain capital recovery factor in place of PNNL's after-tax fixed charge rate. Comparisons in USD 2021 use 1.1827 USD/EUR on both sides: the default 167.8 EUR/MWh is 0.198 USD/kWh. A financier comparing to PNNL's LCOS should add about 9 %.

Market range PNNL-33283 prints two LCOS statements on different scopes, both after tax: USD 0.20-0.40/kWh for all battery systems at 1-10 MW and up to 10 h, and USD 0.13-0.20/kWh for five technologies (gravitational, thermal, LFP, VRFB, NMC) at 100-1,000 MW.

BOUNDS. LCOS 87-400 EUR/MWh = the model's own envelope over the input box (91.6-380.1), rounded outward by about 5 %; it is a domain check of this calculator, not a market range. AC round trip 65-80 % = PNNL 2020 literature range (the cases give 65.49 and 71.94 %). Installed CAPEX 254-507 EUR/kWh = PNNL's USD 300-600/kWh battery band / 1.1827, which also bounds the Customized slider. Input box: energy 4-1,200 MWh with power 1-100 MW, duration 4-12 h, 285-365 equivalent cycles, three reference cases, Model or Customized CAPEX (254-507 EUR/kWh), charging price 20-100 EUR/MWh, real rate 5.06-9.92 %. Enumerated on a 0.05 h duration grid x 21 powers from 1 to 100 MW x cycles {285, 325, 365} x every case x {model, 254, 507} x the price and rate corners (364,392 valid points): LCOS min 91.6 at 100 MW / 10 h, 254 EUR/kWh customized, developer case, 20 EUR/MWh, 5.06 %; max 380.1 at 1 MW / 4 h, 285 cycles, PNNL baseline, 507 EUR/kWh customized, 100 EUR/MWh, 9.92 %. Energy share of CAPEX 56-86 % = its range over the box (59.6 % at 4 h to 81.5 % at 12 h, duration only) widened by about 5 %. On the model CAPEX alone the installed cost spans 312.0-484.3 EUR/kWh.

Market range Not applicable.

CHAINING. The plant takes electricity and returns electricity. Inlet 'Electricity for charging' = annual charge / 8,760 in MW, hourly (2.545 MW average at the defaults); outlet 'Electricity discharged' = annual discharge / 8,760 in MW, hourly (1.667 MW), the main product. No MWh/yearly flows (invariant I3). The inlet is priced by the project, so the meta books NO charging cost in costs.opex (invariant I5); the standalone LCOS keeps the charging price as its own input. Never link the outlet back to this asset's inlet, nor to the source that charges it, or the netting cancels charge against discharge. Both flows are manual_only: power and energy are sized independently, so there is no single input to resize. CAPEX goes to the project as isbl = total installed CAPEX, already all-in (SI + EPC + PD + grid), so battery_limit = fully_financed; 'installed' or 'exfactory' would add the uplift twice (BUG-044). The year-12 stack replacement is not handed over: project mode replaces the whole asset at its 24-year lifetime, so add the stack replacement by hand there.

Market range Not applicable (chaining rule).

LIMITS. Not modelled: taxes, depreciation and construction finance (pre-tax, about 9 % below PNNL's after-tax LCOS); power above 100 MW, outside PNNL's size rule; hourly dispatch, price arbitrage and grid fees (one average charging price); capacity fade and electrolyte rebalancing; end-of-life disposal cost (PNNL's 36.5 USD/kWh sensitivity); land. The 2020 power/energy split is applied to 2021 costs; variable O&M is a 2020 USD value; 351.5 USD/kW is reused for the replacement with no learning curve and no size factor. O&M is calibrated at the 10 MW anchor and not scaled. The electrolyte residual of the buy-back cases is a vendor claim.

Market range Not applicable.