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Green ammonia synthesis (Haber-Bosch)

Techno-economic screening of an electrified Haber-Bosch ammonia plant fed by green hydrogen and ASU nitrogen.

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Open Jack

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Costing

Delivered green hydrogen feed price (priced input, matching IRENA cost decomposition).

EUR/kg

Delivered nitrogen feed price from the cryogenic air separation unit (priced input).

EUR/t

Real discount rate used to compute the capital recovery factor (CRF).

Economic lifetime for levelized cost (linear depreciation basis).

years

Levelized cost of ammonia (LCOA)

Total annual cost divided by annual NH3 output

…EUR/t

Scaled specific synthesis-island CAPEX

Synthesis-island capital intensity after scale curve and clamps

…EUR/(t/y)

Synthesis-island CAPEX

Synthesis loop + ASU + balance of plant (excl. electrolysis)

…EUR

Annualized CAPEX (CRF-based)

Synthesis-island CAPEX as an annual payment equivalent

…EUR/year

Fixed O&M

Annual fixed operating and maintenance cost

…EUR/year

Total annual cost

Annualized CAPEX + O&M + H2 + N2 + electricity + N2 purification

…EUR/year
Scale effect vs nameplate capacity

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Sensitivity to hydrogen price

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Production

Select the synthesis-island configuration. Affects feed intensities, synthesis-island electricity and reference CAPEX.

Nameplate (100% load) ammonia output of the synthesis island. Actual output scales with capacity factor.

Average annual utilization vs nameplate. Drives operating hours and annual NH3 output.

Annual ammonia output

Main product, annualized by capacity factor

…t/y

Annual hydrogen consumption

Green H2 feed required for the synthesis loop

…t/y

Annual nitrogen consumption

N2 feed from the air separation unit (ASU)

…t/y
Sensitivity to capacity factor

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Energy

Annual synthesis-island electricity

Compression + ASU + synthesis (excl. electrolysis)

…MWh/y

Effective synthesis-island electricity intensity

Specific electricity adjusted by part-load penalty

…MWh/t

Total energy intensity (incl. electrolysis)

Cross-check vs C-THRU 37.3 GJ/t and IEA BAT 34.4 GJ/t

…GJ/t

Average delivered electricity price for synthesis-island loads (compression + ASU + synthesis).

EUR/MWh
Sensitivity to electricity price

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Cost breakdown

LCOA breakdown: hydrogen

Hydrogen feed contribution to LCOA

…EUR/t

LCOA breakdown: annualized CAPEX

Capital contribution to LCOA

…EUR/t

LCOA breakdown: synthesis electricity

Synthesis-island electricity contribution to LCOA

…EUR/t

CAPEX breakdown: synthesis loop

Indicative allocation within synthesis-island CAPEX

…EUR

CAPEX breakdown: air separation unit (ASU)

Indicative allocation within synthesis-island CAPEX

…EUR

About

Calculator context

Screening techno-economic model of an electrified Haber-Bosch (HB) plant fed by green hydrogen (electrolysis) and nitrogen from a cryogenic Air Separation Unit (ASU). Reaction N2+3H2->2NH3. Computes annual NH3 output, H2 and N2 consumption, synthesis-island electricity (compression + ASU + synthesis, excluding electrolysis) and the levelized cost of ammonia (LCOA, EUR/t). H2 and N2 are priced inputs, matching the IRENA renewable-ammonia cost decomposition. LCOA = (annualized synthesis-island CAPEX + fixed O&M + H2 cost + N2 cost + synthesis-island electricity + N2 purification) / annual NH3 output. Defaults: CRF(7%,20y)=0.0944, OPEX 3%/y of CAPEX, capacity factor 0.7, H2 0.18 t/t NH3, N2 0.82 t/t NH3, synthesis-island electricity 1.083 MWh/t NH3 (C-THRU/IEA Table 5). Cross-check: total energy 37.3 GJ/t (C-THRU), IEA BAT 34.4 GJ/t, IRENA headline 10 MWh/t; renewable NH3 cost USD 720-1400/t today and USD 310-610/t by 2050. EUR~USD parity assumed for screening.

Model

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

88 variables shown of 88
VariableValueUnitDepends on
1——
100000t/y—
70%—
2EUR/kg—
30EUR/t—
50EUR/MWh—
0.07ratio—
20years—
VariableFormulaUnitDepends on
if((<=0)+((*0.01)<)+((*0.01)>)+(<0)+(<0)+(<0)+(<0)+(<=0)+(<)+(>)>0,1,0)bool
*(*0.01)h/year
clamp(+*(-(*0.01)),,)—
/max(,)t/h
if(==,,)t/t
if(==,,)t/t
*kg/y
if(==,,)MWh/t
*/max(,)MWh/y
+MWh/y
if(==,,)EUR/(t/y)
*(/max(,))^(-)EUR/(t/y)
*EUR
(*(1+)^)/max(((1+)^-1),)—
*EUR/year
VariableFormulaUnitDepends on
*(*0.01)t/y
*t/y
*t/y
*MWh/t
*MWh/y
*/max(,)GJ/t
clamp(,,)EUR/(t/y)
*EUR
*EUR
*EUR
*EUR/year
*EUR/year
*EUR/year
*EUR/year
*EUR/year
+++++EUR/year
/max(,)EUR/t
/max(,)EUR/t
/max(,)EUR/t
/max(,)EUR/t

Assumptions

45 assumptions used in the calculations

  • Prevents division-by-zero and NaN propagation in edge cases.

    Market range Not applicable (numerical parameter).

    0.000001
    Numerical stability constant for division guards.

  • Used for capacity-factor annualization.

    Market range 8760 (non-leap year); 8784 (leap year).

    8760h/year
    Calendar-year hours convention.

  • Converts tonnes to kilograms for hydrogen pricing.

    Market range Exact.

    1000kg/t
    Unit conversion.

  • Converts annual energy to a per-tonne GJ cross-check.

    Market range Exact.

    3.6GJ/MWh
    Unit conversion.

  • Sets the hydrogen feed required per tonne of ammonia.

    Market range 0.178 (stoichiometric) to 0.18 (typical).

    0.18t H2/t NH3
    Stoichiometric + process H2 demand for ammonia synthesis.

  • Hydrogen intensity for the electrified Haber-Bosch configuration.

    0.18t H2/t NH3
    Process H2 demand (electrified route).

  • Hydrogen intensity for the integrated configuration (near-stoichiometric).

    Market range 0.178 (stoichiometric).

    0.178t H2/t NH3
    Stoichiometric H2 demand.

  • Sets the nitrogen feed required per tonne of ammonia.

    0.82t N2/t NH3
    Stoichiometric N2 demand for ammonia synthesis.

  • Nitrogen intensity for the electrified configuration.

    0.82t N2/t NH3
    Process N2 demand (electrified route).

  • Nitrogen intensity for the integrated configuration.

    Market range 0.822 (stoichiometric).

    0.822t N2/t NH3
    Stoichiometric N2 demand.

  • Synthesis-island electricity (compression+ASU+synthesis) per tonne NH3.

    Market range ~3.5-4.5 GJ/t (0.97-1.25 MWh/t).

    1.083MWh/t NH3
    C-THRU Table 5 breakdown (excludes electrolysis).

  • Synthesis-island electricity for the electrified configuration.

    1.083MWh/t NH3
    C-THRU Table 5 breakdown.

  • Synthesis-island electricity for the integrated configuration.

    0.95MWh/t NH3
    AI

  • Electrolysis electricity per kg H2 for the total-energy cross-check.

    53kWh/kg H2
    C-THRU brief electrolyser intensity.

  • Reference total energy intensity for the cross-check output.

    Market range ~36-40 GJ/t.

    37.3GJ/t NH3
    C-THRU Table 5 total.

  • Best-available-technology energy intensity reference.

    Market range ~34-36 GJ/t (BAT).

    34.4GJ/t NH3
    IEA Ammonia Technology Roadmap.

  • IRENA headline total energy intensity (context).

    Market range ~10 MWh/t (36 GJ/t).

    10MWh/t NH3
    IRENA Innovation Outlook.

  • Reference synthesis-island specific CAPEX (excl. power).

    600EUR/(t/y)
    IRENA integrated CAPEX decomposition.

  • Reference specific CAPEX for the electrified configuration.

    600EUR/(t/y)
    IRENA decomposition.

  • Reference specific CAPEX for the integrated configuration.

    500EUR/(t/y)
    AI

  • Reference plant size for the CAPEX scale curve.

    100000t/y
    Scale-curve anchor.

  • Economies of scale for the synthesis island.

    0.75
    Six-tenths-rule-style scaling exponent.

  • Prevents unrealistically low specific CAPEX at very large scale.

    300EUR/(t/y)
    Clamp minimum for scaled specific CAPEX.

  • Prevents unrealistically high specific CAPEX at very small scale.

    1200EUR/(t/y)
    Clamp maximum for scaled specific CAPEX.

  • Synthesis loop (reactor, recycle, refrigeration) share of synthesis-island CAPEX.

    0.55
    Equipment cost allocation share.

  • Air separation unit share of synthesis-island CAPEX.

    0.3
    Equipment cost allocation share.

  • Balance-of-plant share of synthesis-island CAPEX.

    0.15
    Equipment cost allocation share.

  • Fixed O&M as a fraction of synthesis-island CAPEX.

    0.031/year
    O&M fraction of CAPEX.

  • Reference CRF for the IRENA nominal case (cross-check).

    Market range 0.0944 at 7%/20y.

    0.0944
    Capital recovery factor at 7%/20y.

  • Additional nitrogen purification cost per tonne NH3.

    5EUR/t NH3
    IRENA purification cost adder.

  • Default delivered green hydrogen price.

    2EUR/kg
    IRENA green H2 cost outlook.

  • Default delivered nitrogen price from the ASU.

    30EUR/t
    ASU nitrogen cost screening value.

  • Default electricity price for synthesis-island loads.

    50EUR/MWh
    Renewable LCOE screening value.

  • Default annual utilization of the plant.

    0.7
    IRENA renewable-ammonia load factor.

  • Default real discount rate for CRF.

    0.07
    IRENA financing assumption.

  • Default economic lifetime for levelized cost.

    20years
    IRENA depreciation horizon.

  • Screening part-load penalty coefficient (off by default).

    0
    Utilization/part-load penalty coefficient.

  • Prevents the penalty from improving performance below the reference intensity.

    Market range 1 (by definition).

    1
    Clamp lower bound for the penalty factor.

  • Avoids unrealistically large penalties at low capacity factors.

    1.3
    Clamp upper bound for the penalty factor.

  • Required because the DSL has no strings.

    Market range Not applicable.

    1
    Numeric selector encoding.

  • Required because the DSL has no strings.

    Market range Not applicable.

    2
    Numeric selector encoding.

  • Validates the selector domain.

    1
    Input validation bound.

  • Validates the selector domain.

    2
    Input validation bound.

  • Avoids inline literals in DSL expressions per spec.

    Market range Exact.

    1
    Numeric constant.

  • Avoids inline literals in the validation guard.

    Market range Exact.

    0
    Numeric constant.

Sources

Primary reference

IRENA (2022) Innovation Outlook: Renewable Ammonia; C-THRU Ammonia Technical Brief (2022)