CostingEnergy mass balanceAmmonia

Small modular green ammonia plant: flexible Haber-Bosch loop, cost excluding hydrogen

Flexible Haber-Bosch loop with N2 purification, H2 buffer and NH3 storage, 1 to 300 t/d: ammonia cost excluding hydrogen and total cost in EUR/t, annual output, electricity per tonne and H2 buffer, with the small-size scale penalty from Palys 2018 and IRENA 2022.

Open Jack

Founder · OpenJack

Add to project

CurrencyEUR 2021
Battery limitinstalled
59 documented assumptions
Updated27 Oct 2026

Mass and energy balance

What the asset draws and delivers for the case and load you choose.

Reference case

Mean operating load

Mean load of the flexible loop over the year, as a share of nameplate. Default 70 %, IRENA's full-load fraction for hybrid PV and wind. It sets the annual output and the loop energy per tonne (fixed losses spread over less ammonia at low load). The loop turns down to 10-30 % of nameplate (IRENA).

Flows

Annual quantities at the current usage. Outline: full capacity, 8,760 h. Fill: 70.0 % capacity factor. Band width: share of energy in; non-energy flows are not to scale.

Ammonia output (nameplate)

Nameplate ammonia output of the Haber-Bosch loop at full load. This is the capacity the catalogue binds on (Casale Neptun Glomfjord 100 t/d, Skiga Skipavika 300 t/d). Sourced cost domain: the anchor is a 3 t/d quote and the source applies its 0.67 law up to 145 t/d. Below 3 t/d the CAPEX is extrapolated (flagged); above 145 t/d only an IRENA cross-check supports it.

Ammonia output rate at full load: — kg/h
Hydrogen feed at full load: — kg/h
Power draw at full load: — MW

CAPEX

Specific cost at this size, what backs it, and how it behaves with scale.

Specific CAPEX at this size

—

Reference size 3 t/d

Palys et al. 2018, section 6

Loop CAPEX source

Model value: the 3 t/d Palys quote scaled with the 0.67 exponent. Customized: your own installed loop CAPEX per t/d, used as is at every size; the value is then no longer sourced. The H2 buffer and the rest of plant keep their model values.

Loop specific CAPEX by ammonia output (nameplate)

Ex-factory
Installed· this figure
Fully financed

CAPEX at the battery limit—

Working capital, contingencyproject level

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.

Small-scale modular green ammonia plant (flexible Haber-Bosch loop)Concept sketch, not to scale · drag to rotate

Hydrogen in: —
Electricity for loop and N2 purification in: —
Ammonia outMain product: —
CAPEX to the battery limit: —
Fixed O&M: —
Variable O&M, excluding feedstocks: 0 EUR/year
Asset lifetime: 20 years

Ammonia cost excluding hydrogen

A standalone indicator for a quick read. Project mode recomputes it for the whole system.

—

Cost: capital—
Cost: fixed O&M—
Cost: electricity—

Linked to the balance above

Mean operating load

H2 buffer duration

Hours of nameplate hydrogen feed held in above-ground pressure vessels, to smooth the intermittent electrolysis. Default 24 h, IRENA's one-day-equivalent. A more flexible loop needs less buffer.

Electricity price

Price of the loop and N2 purification electricity (not the electrolyser). Default 40 EUR/MWh, the Norway case of Sousa et al. 2022; slider over their 20-60 EUR/MWh sensitivity.

Hydrogen price

Delivered price of the hydrogen fed to the loop. Default 6 EUR/kg (Sousa et al. 2022: most European H2 sold above 6 EUR/kg; range 4-10). Not part of the cost excluding hydrogen.

Discount rate

Real rate of the capital recovery factor. Default 7 %, the IRENA 2022 convention.

Economic lifetime

Economic life of the plant. Default 20 years, the IRENA 2022 convention.

Ammonia cost excluding hydrogen by mean operating load

Benchmarks

This model's figures against published references and reference cases.

Loop electricity per kg, kWh/kg

0.64 Palys et al. 2018, section 6

2.12 Palys et al. 2018, section 6

Loop CAPEX per t/a of capacity, USD/(t/a)

1,000 IRENA 2022, p. 39

One-day buffer cost per tonne, USD/t

35 IRENA 2022, p. 46

150 IRENA 2022, p. 46

Reference cases at this size and usage

All results

Every model output at the current settings, grouped, with the sensitivity charts.

48 outputs · 8 groups · 16 also shown above, dimmed

Cost of ammonia

Ammonia cost excluding hydrogen: ComputingEUR/t
Cost: capital: ComputingEUR/t
Cost: fixed O&M: ComputingEUR/t
Cost: electricity: ComputingEUR/t
Capital share of cost excluding hydrogen: Computing%

Cost by plant block

Capital and O&M: HB loop: ComputingEUR/t
Capital and O&M: H2 buffer: ComputingEUR/t
Capital and O&M: rest of plant: ComputingEUR/t

Hydrogen

Total ammonia cost: ComputingEUR/t
Hydrogen cost per tonne: ComputingEUR/t
Hydrogen share of total cost: Computing%
Hydrogen bought a year: Computingt/a
Hydrogen feed at full load: Computingkg/h
Stoichiometric hydrogen from molar masses: Computingkg/t
H2 buffer: Computingkg

CAPEX and scale

Total CAPEX: ComputingEUR
HB loop CAPEX: ComputingEUR
H2 buffer CAPEX: ComputingEUR
Rest-of-plant CAPEX: ComputingEUR
Loop specific CAPEX: ComputingEUR/(t/d)
Scale exponent applied: Computingratio
Total specific CAPEX: ComputingEUR/(t/d)

Reference checks

Loop CAPEX per t/a of capacity: ComputingUSD/(t/a)
Loop CAPEX against IRENA large-plant ceiling: Computing%
One-day buffer cost per tonne: ComputingUSD/t
Loop electricity per kg: ComputingkWh/kg
Below sourced size domain: Computingbool
Above direct anchor range: Computingbool
Below typical turndown: Computingbool

Production

Annual ammonia output: Computingt/a
Ammonia output rate at full load: Computingkg/h
Equivalent full-load hours: Computingh/year

Energy balance

Electricity per tonne: ComputingkWh/t
Loop energy per tonne: ComputingGJ/t
Part-load energy penalty: Computingratio
Part-load extra electricity: ComputingkWh/t
N2 purification energy: ComputingGJ/t
Electricity a year: ComputingMWh/year
Average power draw: ComputingMW
Power draw at full load: ComputingMW
Synthesis efficiency (LHV): Computing%
Heat and losses: ComputingMWh/year

Yearly costs

Capital recovery factor: Computing1/year
Annualised CAPEX: ComputingEUR/year
Fixed O&M a year: ComputingEUR/year
Electricity cost a year: ComputingEUR/year
Annual cost excluding hydrogen: ComputingEUR/year
Annual cost including hydrogen: ComputingEUR/year

Sensitivities

6 charts

Cost excluding hydrogen by component vs mean load

Loop specific CAPEX and cost excluding hydrogen vs nameplate

Cost excluding hydrogen by plant block, per reference case

H2 buffer size and its cost vs buffer duration

Electricity per tonne vs mean load

Total ammonia cost vs hydrogen price

Sources

59 documented assumptions · 6 sources

About

Calculator context

Small modular green ammonia plant whose boundary is hydrogen in, ammonia out: a flexible Haber-Bosch loop with its compression, N2 purification, a hydrogen buffer that smooths intermittent electrolysis, and ammonia storage. The electrolyser is outside; hydrogen is bought at an input price. The calculator gives the cost of ammonia excluding hydrogen in EUR per tonne, split into capital, fixed O&M and electricity, and by plant block; the total cost with hydrogen; the annual output; the electricity per tonne, which rises at low load; and the size of the hydrogen buffer. At the defaults (100 t/d, 70 % mean load, conservative case, 24 h buffer, 40 EUR/MWh, 6 EUR/kg H2, 7 %, 20 years) the cost excluding hydrogen is 302 EUR/t and the total 1,367 EUR/t, for 25,550 t a year, 1,022 kWh/t and a 17,760 kg buffer. The same plant at 1 t/d costs 883 EUR/t excluding hydrogen, and 252 EUR/t at 300 t/d. The loop CAPEX scales from a 3 t/d quote (Palys et al. 2018) with the 0.67 exponent, so the specific CAPEX rises sharply at small size; buffer vessels use the DOE 1000 or 700 USD/kg; the rest of plant and the finance follow IRENA's 2022 Innovation Outlook (5-30 USD/t, 7 %, 20 years, 3 % O&M, 70 % load), and the loop energy at part load is a fit on IRENA's 2.2 and 14.4 GJ/t points. Below 3 t/d the CAPEX is extrapolated and above 145 t/d only an IRENA cross-check supports it: both are flagged. Costs are converted at 0.84 EUR/USD and not escalated. Chains downstream of an electrolyser calculator through its hydrogen inlet.

Model

116 variables — inputs, calculations and outputs, with their dependencies.

116 variables shown of 116

Value	Unit	Depends on
100	t/d	—
70	%	—
1	—	—
24	h	—
0	—	—
1000000	EUR/(t/d)	—
40	EUR/MWh	—
6	EUR/kg	—
7	%	—
20	years	—

Variable	Formula	Unit	Depends on
	`if((<=)+(<)+(>)+(<)+(>)+(<)+(<)+(>)+(<=)+(<)+(<)+(<)+(>)+(<)>,,)`	bool
	`*`	ratio
	`*`	ratio
	`(-)/(/-)`	GJ/t
	`-`	GJ/t
	`+`	GJ/t
	`*/`	EUR/(t/d)
	`if(==,,)`	USD/kg
	`if(==,,)`	USD/t
	`(*(+)^)/max((+*)^-,)`	1/year

Variable	Formula	Unit	Depends on
	`*`	h/year
	`/`	kg/t
	`**`	t/a
	`*/`	kg/h
	`*/`	kg/h
	`*/`	t/a
	`*`	kg
	`+/max(,)`	GJ/t
	`/`	ratio
	`if(==,,)`	GJ/t
	`*`	kWh/t
	`*/`	kWh/kg
	`(-)*`	kWh/t
	`**`	MWh/year
	`/`	MW
	`(+)*/`	MW
	`/(+)*`	%
	`(+-)`	MWh/year
	`if(<,/,(*(+)^)/max((+)^-,))`	1/year
	`if(>=,,)`	ratio
	`if(>=,,clamp(*(/)^(-),,))`	EUR/(t/d)
	`*`	EUR
	`**`	EUR
	`****/(+)`	EUR
	`++`	EUR
	`/`	EUR/(t/d)
	`//(*)`	USD/(t/a)
	`/*`	%
	`*`	EUR/year
	`**`	EUR/year
	`*`	EUR/year
	`++`	EUR/year
	`/max(,)`	EUR/t
	`/max(,)`	EUR/t
	`**`	EUR/t
	`++`	EUR/t
	`(+)/max(,)`	EUR/t
	`(+)/max(,)`	EUR/t
	`(+)/max(,)`	EUR/t
	`**(+)/max(,)`	USD/t
	`*`	EUR/t
	`+`	EUR/t
	`/max(,)*`	%
	`/max(,)*`	%
	`+**`	EUR/year
	`if(<,,)`	bool
	`if(>,,)`	bool
	`if(<,,)`	bool

Assumptions

59 assumptions used in the calculations

Zero used in the guards and flags.
Market range Exact by definition.
0
Numerical constant
Unit multiplier in the CRF, the guards, the reference-case switch and the Customized switch.
Market range Exact by definition.
1
Numerical constant
Prevents a division by zero; far too small to change a result.
Market range Not a market value.
0
Numerical guard
Converts a percent into a fraction.
Market range Exact by definition.
0.01
Numerical constant
Converts a fraction into a percent; also the 100 % upper limit of the load guard.
Market range Exact by definition.
100
Numerical constant
Calendar hours used to annualise the load and the average power.
Market range Exact by definition.
8760h/year
Numerical constant
Days in a year, to turn a daily nameplate into a yearly output.
Market range Exact by definition.
365d/year
Numerical constant
Hours in a day, to turn a daily nameplate into an hourly flow; also the 24 h maximum of the buffer guard.
Market range Exact by definition.
24h/d
Numerical constant
Mass conversion.
Market range Exact by definition.
1000kg/t
Numerical constant
Energy conversion.
Market range Exact by definition.
0.001MWh/kWh
Numerical constant
Energy conversion, 1 GJ = 1000/3.6 kWh.
Market range Exact by definition.
277.777778kWh/GJ
Numerical constant
Identifier of the conservative reference case in the selector.
Market range Exact by definition.
1
Numerical constant
Identifier of the optimistic reference case in the selector.
Market range Exact by definition.
2
Numerical constant
Derives the stoichiometric hydrogen need from the reaction N2 + 3 H2 -> 2 NH3.
Market range Exact to the third decimal.
2.016g/mol
IUPAC atomic weights
Derives the stoichiometric hydrogen need from the reaction N2 + 3 H2 -> 2 NH3.
Market range Exact to the third decimal.
17.031g/mol
IUPAC atomic weights
Moles of hydrogen per mole of ammonia.
Market range Exact.
1.5mol/mol
Reaction stoichiometry
Hydrogen bought per tonne of ammonia, assuming full conversion of the loop purge (no hydrogen loss). Also shown recomputed from the molar masses.
Market range 177.6 kg/t is the stoichiometric minimum; real plants lose some hydrogen in the purge, not modelled.
177.6kg/t
Stoichiometry from IUPAC molar masses
Lower heating value of the hydrogen fed; used only for the energy balance (efficiency, losses), not for the cost.
Market range 33.3 kWh/kg LHV.
33.3kWh/kg
NAP 2004, appendix
Lower heating value of the ammonia produced; used only for the energy balance (efficiency, losses).
Market range 18.6 GJ/t (IRENA); no other value used.
18.6GJ/t
IRENA 2022 hydrogen trade Part II, p. 33
Cost anchor of the Haber-Bosch loop: a vendor quote for a 3 t/d unit, the only small-scale quote in the sources. Nominal dollars of the quote, not escalated.
Market range Single quote; its scope (installation, N2 supply) is not published. No independent range cited.
3800000USD
Palys et al. 2018, section 6
Size of the cost anchor; the scale law is pinned at this output.
Market range Single anchor at 3 t/d.
3t/d
Palys et al. 2018, section 6
Economy of scale of the loop CAPEX with the ammonia output. Specific CAPEX falls as output^-0.33, which is the diseconomy of small sizes this calculator is about.
Market range 0.67 is the generic chemical-industry exponent; no ammonia-specific exponent for small loops is cited. A single exponent on a single anchor is a medium-evidence law.
0.67
Palys et al. 2018, section 6
Below this output the scale law is extrapolated and the out-of-sourced-domain flag is raised.
Market range Single anchor.
3t/d
Palys et al. 2018, section 6
Largest output where the source itself applies the 0.67 law; above it the only support is the IRENA large-plant cross-check.
Market range Single source.
145t/d
Palys et al. 2018, section 6
Order-of-magnitude cross-check of the loop CAPEX at the top of the slider, per tonne a year of nameplate capacity. A cross-check, not a validation: it is an upper bound for large plants and its scope includes N2 purification.
Market range Below USD 1000 per t/a for large plants (IRENA); no small-scale value cited.
1000USD/(t/a)
IRENA 2022, p. 39
Clamp floor of the scale law. It would bite only above about 3,900 t/d, far outside the slider; it never changes a value inside the declared domain.
Market range Not a market value.
100000EUR/(t/d)
Numerical guard
Clamp ceiling of the scale law. It would bite only below about 0.13 t/d, outside the slider; it never changes a value inside the declared domain.
Market range Not a market value.
3000000EUR/(t/d)
Numerical guard
Loop electricity (compression and recycle) per tonne at full load; first of the two points of the load curve.
Market range Single study (Banares-Alcantara 2015) reported by IRENA.
2.2GJ/t
IRENA 2022, section 2.4
Loop electricity per tonne at 10 % load; second point of the load curve. The fixed losses (heat, recycle) are spread over less ammonia.
Market range Single study reported by IRENA.
14.4GJ/t
IRENA 2022, section 2.4
Load at which the second energy point is published; used to fit e(L) = a + b/L through the two points.
Market range Exact as published.
10%
IRENA 2022, section 2.4
Lowest load reported for a flexible loop; a mean load below it is refused as outside the model.
Market range
10%
IRENA 2022, p. 46
Upper end of the published turndown; a mean load below it raises the below-typical-turndown flag.
Market range
30%
IRENA 2022, p. 60
N2 supply electricity per tonne, optimistic case.
Market range
0.6GJ/t
IRENA 2022, section 3.1
N2 supply electricity per tonne, conservative case (default): small plants sit at the top of the range.
Market range
0.9GJ/t
IRENA 2022, section 3.1
Benchmark for the loop electricity per kg: an independent value for a 100 t/d loop at full load.
Market range 0.64 kWh/kg at 100 t/d; 2.12 kWh/kg for a 3 kg/h unit.
0.64kWh/kg
Palys et al. 2018, section 6
Benchmark for the loop electricity per kg at very small size (3 kg/h, about 0.07 t/d): shows that the model, which has no size effect on energy, is optimistic below a few t/d.
Market range Single small-scale value.
2.12kWh/kg
Palys et al. 2018, section 6
Above-ground pressure vessels for the H2 buffer, conservative case (default). Vessels are modular, so the cost is linear in the stored mass (no scale law).
Market range 1000 USD/kg (FY2011 status) to 700 USD/kg (FY2020 target), purchased cost of low-pressure vessels.
1000USD/kg
ORNL 2012, Table 1
H2 buffer vessels, optimistic case.
Market range 1000 to 700 USD/kg.
700USD/kg
ORNL 2012, Table 1
Benchmark, low end, for the levelised cost of a one-day H2 buffer.
Market range USD 35-150/t (IRENA).
35USD/t
IRENA 2022, p. 46
Benchmark, high end, for the levelised cost of a one-day H2 buffer.
Market range USD 35-150/t (IRENA).
150USD/t
IRENA 2022, p. 46
Buffer duration of the IRENA benchmark; also the default of the buffer input.
Market range IRENA reference: one day.
24h
IRENA 2022, p. 46
Rest of the plant (N2 PSA or ASU, desalination, NH3 storage) as a levelised investment, optimistic case.
Market range USD 5-30/t (IRENA).
5USD/t
IRENA 2022, p. 44
Rest of the plant, conservative case (default): top of the range, since small plants carry a scale penalty that the source does not quantify.
Market range USD 5-30/t (IRENA).
30USD/t
IRENA 2022, p. 44
Fixed O&M a year as a share of the whole CAPEX (loop, buffer and rest of plant).
Market range 3 % (IRENA); no independent range cited.
3%
IRENA 2022, Figure 17
Rate of IRENA's own levelising convention: used only to turn the IRENA USD/t rest-of-plant figure back into an investment. Also the default of the discount rate input.
Market range 7 % (IRENA).
7%
IRENA 2022, Figure 17
Life of IRENA's levelising convention, used to convert the rest-of-plant figure; also the default of the lifetime input.
Market range 20 years (IRENA).
20years
IRENA 2022, Figure 17
Load at which IRENA levelises its figures: converts the rest-of-plant USD/t back into an investment at nameplate. Also the default of the load input.
Market range Around 70 % for hybrid PV and wind (IRENA).
70%
IRENA 2022, p. 45 and Figure 17
Converts the dollar costs to euros, with the exchange rate of a European green-ammonia study. Costs keep the nominal year of their source and are not escalated.
Market range 0.84 EUR/USD in September 2021; no index applied.
0.84EUR/USD
Sousa et al. 2022, p. 7
Default of the electricity price input (20-60 EUR/MWh slider, the source's sensitivity range).
Market range
40EUR/MWh
Sousa et al. 2022, p. 4
Default of the hydrogen price input (4-10 EUR/kg slider, the source's range).
Market range
6EUR/kg
Sousa et al. 2022, p. 9
Context only, low end. It includes electrolysis and renewable power, so it is not comparable figure for figure with the total cost here, which buys hydrogen at an input price; no position is concluded from it.
Market range USD 720-1400/t in 2020 (IRENA).
720USD/t
IRENA 2022, p. 44
Context only, high end (see low end).
Market range USD 720-1400/t in 2020 (IRENA).
1400USD/t
IRENA 2022, p. 44
Plant boundary: hydrogen in, ammonia out. Electrolysis is outside; hydrogen is bought at an input price. Annual output = nameplate x 365 x mean load. CAPEX = HB loop (scaled quote) + H2 buffer (vessels, linear in kg) + rest of plant (IRENA USD/t turned back into an investment at IRENA's own convention). Cost excluding hydrogen = annualised CAPEX + 3 % O&M, per tonne, plus loop and N2 electricity. Total = that plus 177.6 kg of hydrogen at its price.
Market range Not applicable.
—
Model scope
Loop electricity versus load is a two-parameter fit e(L) = a + b/L on the only two published points: a fixed loss spread over less ammonia at low load. It is evaluated at the mean load, which slightly understates the energy of a loop that swings between low and full load. Compression to fill the H2 buffer is not counted (no source).
Market range Not applicable.
—
Model scope
The scale law rests on one quote at 3 t/d. Below 3 t/d it is extrapolated (flagged), and IRENA notes higher loop energy under 10 t/d from heat losses, which the model does not capture; Palys reports 2.12 kWh/kg for a 3 kg/h unit. Between 3 and 145 t/d the source applies the law itself. Above 145 t/d there is no direct anchor; at 300 t/d the loop costs about 760 USD per t/a of nameplate, consistent with IRENA's 'typically below USD 1 000 per t/a' for large loop-only plants. This is a consistency check, not a validation.
Market range Not applicable.
—
Model scope
N2 supply (PSA or ASU), desalination and ammonia storage are one IRENA figure, 5-30 USD/t, converted back into an investment at nameplate with IRENA's own convention (7 %, 20 years, 3 % O&M, 70 % load). No sourced scaling law exists for them, so the ASU cost is NOT scaled with size: a small plant probably pays more than the 30 USD/t top of the range. It may slightly double count if the 3.8 MM$ quote already included N2 supply.
Market range Not applicable.
—
Model scope
battery_limit = installed: the HB quote is read as an installed packaged unit, so project mode adds only the working layer and contingency (about x1.17). The quote's scope is not published and the vessel cost is a purchased cost, so the evidence is low. If your quote is ex-works, enter an installed value with Customized.
Market range Not applicable.
—
Model scope
Dollar costs are converted at 0.84 EUR/USD and keep the nominal year of their source (quote 2018, DOE status 2011, IRENA 2020-2022): they are NOT escalated to a common year. The discount rate is read as a real rate on these constant costs.
Market range Not applicable.
—
Model scope
Out of V1: the electrolyser and its coupling to the renewables profile, the inert-dilution turndown mode, a sourced ASU scaling law, hydrogen losses in the loop purge, buffer compression energy, and catalyst replacement beyond the 3 % O&M.
Market range Not applicable.
—
Model scope