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CO2 methanation (Sabatier, power-to-gas)

Screening synthetic natural gas (SNG) output and levelized cost (EUR/MWh) for catalytic CO2 methanation from green hydrogen and captured CO2.

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Open Jack

Founder · OpenJack

Inputs

Nameplate synthetic natural gas output power (LHV).

kW

min 100 · max 100000 · step 100 · kW

Average annual utilization relative to rated power.

min 5 · max 100 · step 1 · %

Chemical LHV efficiency H2 -> CH4. Default 0.75 reflects real catalytic PtG plants (~70-78%); Goetz theoretical ceiling ~78%. Drives H2 demand, which dominates cost.

min 0.5 · max 0.85 · step 0.01 · fraction

Fraction of CO2 converted to CH4 (multi-stage ~98%). Applies to CO2 feed sizing only.

min 0.8 · max 1 · step 0.01 · fraction

Delivered green hydrogen price (dominant cost driver).

EUR/kg

min 0 · max 20 · step 0.5 · EUR/kg

Captured CO2 cost (point-source ~60-80 EUR/t; DAC higher).

EUR/t

min 0 · max 300 · step 5 · EUR/t

Methanation CAPEX per kW SNG at reference size (Goetz/Outotec ~400 at 5 MW).

EUR/kW

min 100 · max 1500 · step 10 · EUR/kW

Annual O&M as a fraction of CAPEX (Frontiers ~5%).

min 0 · max 0.2 · step 0.005 · fraction

Used to compute the capital recovery factor (CRF).

min 0 · max 0.2 · step 0.005 · ratio

Economic lifetime for CAPEX annualization (PtG ~20 yr).

years

min 1 · max 40 · step 1 · years

Results

Annual SNG output (LHV)

…MWh/year

Specific H2 consumption

…kg/MWh

Annual SNG mass

…kg/year

Annual hydrogen demand

…kg/year

Annual CO2 demand

…t/year

Methanation CAPEX

…EUR

Annualized CAPEX

…EUR/year

Total annual cost

…EUR/year

Levelized cost of SNG

…EUR/MWh

About

Calculator context

Screening calculator for catalytic CO2 methanation (Sabatier: CO2 + 4 H2 -> CH4 + 2 H2O) producing synthetic natural gas. Computes annual SNG energy, hydrogen and CO2 feed demand, annualized CAPEX via the capital recovery factor, and the levelized cost of SNG (EUR/MWh, LHV). Grounded on Goetz et al. (2016) Renewable Power-to-Gas review (efficiency, conversion, CAPEX), Frontiers in Energy Research (2021) techno-economics, IRENA/IEA hydrogen and CO2 price references. Hydrogen feedstock dominates the cost.

Model

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

42 variables shown of 42
VariableValueUnitDepends on
5000kW—
85%—
0.75fraction—
0.98fraction—
5EUR/kg—
70EUR/t—
400EUR/kW—
0.05fraction—
0.08ratio—
20years—
VariableFormulaUnitDepends on
if((<=)+((*0.01)<)+((*0.01)>)+(<=)+(>)+(<=)+(>)+(<)+(<)+(<=)+(<)+(<)+(<=)>,,)bool
* (*0.01)h/year
clamp( + * ( - (*0.01)), , )fraction
* clamp(( / )^, , )EUR/kW
if(<,/max(,), * ( + )^ / max(( + )^ - , ))fraction
* EUR/year
* EUR/year
* EUR/year
VariableFormulaUnitDepends on
* / MWh/year
* / kg/year
/ max(, ) / * kg/MWh
* kg/year
* / max(, ) / t/year
* EUR
* EUR/year
+ + + EUR/year
/ max(, )EUR/MWh

Assumptions

12 assumptions used in the calculations

  • Structural unit constant for comparisons, penalty and CRF.

    1
    Dimensionless structural constant.

  • Structural zero constant for guards.

    0
    Dimensionless structural constant.

  • Mass unit conversion t to kg.

    Market range Exact.

    1000kg/t
    SI unit conversion (exact).

  • Lower heating value of methane (50 MJ/kg).

    Market range 13.9 kWh/kg (LHV); 15.4 (HHV).

    13.9kWh/kg
    TU Delft heating-value table.

  • Lower heating value of hydrogen for the H2 energy demand.

    Market range 33.3 (LHV); 39.4 (HHV).

    33.33kWh/kg
    US DOE / NREL.

  • Stoichiometric CO2 per CH4 mass (44.01/16.04).

    Market range 2.744 (stoichiometric).

    2.744kg/kg
    Sabatier stoichiometry CO2 + 4 H2 -> CH4 + 2 H2O.

  • Part-load efficiency penalty coefficient on H2 demand.

    0.05
    Screening simplification.

  • Upper clamp on part-load penalty.

    1.5
    Modeling guardrail.

  • Reference SNG power at which specific CAPEX is quoted.

    5000kW
    Goetz/Outotec 5 MW = 400 EUR/kW.

  • Economy-of-scale exponent for methanation CAPEX vs SNG power.

    Market range -0.1 to -0.3.

    -0.15
    Screening power-law; Goetz 400->130 EUR/kW over 5->110 MW.

  • Lower clamp on the CAPEX scaling multiplier.

    0.4fraction
    Modeling guardrail.

  • Upper clamp on the CAPEX scaling multiplier.

    3fraction
    Modeling guardrail.

Sources

Primary reference

Goetz et al. 2016 (Renewable Energy); Frontiers in Energy Research 2021; IRENA; IEA