Skip to main content
Library

Equipment sizingCostingCarbon capture

Biogas Upgrading & CO2 Separation (Biomethane + CO2-Rich Stream)

Calculator for biomethane production, CO2 separation (biogenic CO2 captured), methane slip, electricity use, CAPEX/OPEX, and levelized cost (EUR/tCO2 captured) for a biogas upgrading unit.

Photo of alexi

alexi

I do low-carbon energy stuff for 10 years & build things I wish existed.

Inputs

Select the main CH4/CO2 separation technology. This sets default electricity intensity and CAPEX/O&M scaling assumptions.

If enabled, adds a simplified CAPEX and electricity adder for methane slip treatment (e.g., thermal/catalytic oxidation).

Nominal inlet biogas flow to the upgrading unit at normal conditions (Nm3/h).

min 10 · max 5000 · step 10 · Nm3/h

Vol-% methane in the inlet biogas (typical: 60–70%). Ensure CH4% + CO2% <= 100%.

min 30 · max 80 · step 1 · %

Vol-% CO2 in the inlet biogas (typical: 30–40%). Ensure CH4% + CO2% <= 100%.

min 10 · max 70 · step 1 · %

Target methane concentration in the upgraded biomethane stream.

min 90 · max 99.9 · step 0.1 · %

Fraction of inlet methane not recovered to biomethane (off-gas / purge / vent). Typical ranges depend on technology and operation.

Average operating fraction over the year, including downtime.

Results

Raw biogas feed capacity

Nominal inlet flow to upgrading unit

…Nm3/h

Biomethane product flow

Based on methane recovery and target CH4 purity

…Nm3/h

Biogenic CO2 captured (separated)

CO2 removed from biogas and routed to CO2-rich stream

…tCO2/year

Methane slip (loss)

CH4 not recovered to biomethane

…kgCH4/h

CO2 capture rate

Separated CO2 as % of CO2 in feed

…%
CO2 capture rate vs. Biomethane purity required

Log in to view this sensitivity chart.

Design

Number of parallel upgrading trains

Ceiling(capacity / unit train capacity)

…count

Average electrical load

Based on specific electricity per Nm3 raw biogas

…kW

Specific electricity per tCO2 captured

Useful for CO2 management benchmarking

…kWh/tCO2

Levelized Costs

Amortization period for CAPEX annualization (CRF).

year

Real or nominal discount rate used for annualizing CAPEX (consistent with your cost basis).

ratio

Levelized cost of CO2 captured

EUR per tonne of biogenic CO2 separated

…EUR/tCO2

Total installed CAPEX (screening)

Scaled with plant size and technology; optional off-gas treatment adder

…EUR

Blended electricity price paid by the upgrading plant.

EUR/MWh

Implied levelized cost per biomethane energy

Total annual cost divided by biomethane energy output

…EUR/MWh
LCO CO2

Log in to view this sensitivity chart.

About

Calculator context

Introduction

This calculator provides a pre-feasibility screening estimate for an integrated biogas upgrading and CO₂ separation unit that converts raw (or pretreated) biogas into grid-/fuel-grade biomethane while producing a CO₂-rich biogenic stream. It is designed for early-stage development decisions in a generic EUR-based context (no region specified) and aligns with common literature-based performance ranges for upgrading technologies.

Key references include IEA Bioenergy Task 37 (biogas upgrading technology performance ranges) and widely used energy-costing conventions (annualization via Capital Recovery Factor, CRF) used across IEA/IRENA/NREL-style techno-economic screening.

Methodology

The model is a mass-balance and parametric-costing spreadsheet expressed as engineering nodes:

  • Feed and product gas balances (Nm3/h)

    • CH4_feed = Q_raw · x_CH4
    • CO2_feed = Q_raw · x_CO2
    • CH4_slip = CH4_feed · L_CH4
    • CH4_recovered = CH4_feed − CH4_slip
    • Biomethane_flow = CH4_recovered / max(y_CH4_biomethane, eps)
    • CO2_in_biomethane = max(Biomethane_flow − CH4_recovered, 0)
    • CO2_separated = max(CO2_feed − CO2_in_biomethane, 0)

  • CO₂ capture accounting

    • CO2_captured (t/yr) = CO2_separated · ρ_CO2 · hours / 1000
    • Capture_rate (%) = 100 · CO2_separated / max(CO2_feed, eps)

  • Electricity use (technology-dependent)

    • Annual_electricity (MWh/yr) = Q_raw · e_spec · hours / 1000
    • Specific_electricity (kWh/tCO2) = Annual_electricity·1000 / max(CO2_captured, eps)

  • Costing (screening-scale parametrics)

    • CRF = (r*(1+r)^n)/max(((1+r)^n-1),eps)
    • specific_capex_scaled = clamp(specific_capex_ref · (Q/Q_ref)^(α−1), min, max)
    • om_fraction_scaled = clamp(om_ref · (Q/Q_ref)^(β), min, max)
    • Annualized CAPEX = CAPEX_total · CRF
    • Total annual cost = Annualized CAPEX + Fixed O&M + Electricity + Pretreatment
    • Levelized cost = Total annual cost / max(CO2_captured, eps) in EUR/tCO₂ captured

Performance ranges for electricity consumption and typical methane losses are guided by IEA Bioenergy Task 37 (e.g., PSA, water scrubbing, membranes, chemical scrubbing).

Applications

  • Project developer: compare upgrading technology options (membrane vs PSA vs water/chemical scrubbing) and identify cost drivers (electricity price, methane loss).
  • BD / early engineering: estimate CO₂ captured (t/yr) and EUR/tCO₂ captured for integration with CO₂ utilization/storage screening.
  • Investment pre-screen: size modular trains (n_units) and approximate CAPEX/OPEX sensitivity versus plant scale and operating hours.

Model

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

92 variables shown of 92
VariableValueUnitDepends on
1——
1000Nm3/h—
65%—
35%—
97%—
1.5%—
90%—
80EUR/MWh—
0——
0.08ratio—
15year—
VariableFormulaUnitDepends on
if((if(<=0,1,0)+if(<0,1,0)+if(>100,1,0)+if(<0,1,0)+if(>100,1,0)+if((+)>100,1,0)+if(<=0,1,0)+if(>100,1,0)+if(<0,1,0)+if(>100,1,0)+if(<0,1,0)+if(>100,1,0)+if(<0,1,0)+if(!=0,if(!=1,1,0),0)+if(<0,1,0)+if(>1,1,0)+if(<=0,1,0)+if(==1,0,if(==2,0,if(==3,0,if(==4,0,1)))) )>0,1,0)bool
*—
*—
*—
*—
**h/year
*Nm3/h
*Nm3/h
*Nm3/h
-Nm3/h
max(-,0)Nm3/h
max(-,0)Nm3/h
+Nm3/h
if(==1,,if(==2,,if(==3,,)))kWh/Nm3
+*kWh/Nm3
(**)/max(,)MWh/year
*EUR/year
**EUR/year
if(==1,,if(==2,,if(==3,,)))EUR/(Nm3/h)
if(==1,,if(==2,,if(==3,,)))—
*(/max(,))^(-1)EUR/(Nm3/h)
clamp(,,)EUR/(Nm3/h)
*EUR
if(==1,,if(==2,,if(==3,,)))—
if(==1,,if(==2,,if(==3,,)))—
*(/max(,))^()—
clamp(,,)—
(*(1+)^)/max(((1+)^-1),)—
*EUR/year
*EUR/year
(***)/max(,)MWh/year
VariableFormulaUnitDepends on
Nm3/h
max(ceil(/max(,)),1)count
/max(,)Nm3/h
(**)/max(,)tCO2/year
if(>0,(*)/max(,),0)%
*kW
(*)/max(,)kWh/tCO2
*(1+*)EUR
+++EUR/year
/max(,)EUR/tCO2
/max(,)EUR/MWh
*kgCH4/h

Assumptions

38 assumptions used in the calculations

  • Prevents division-by-zero and unstable results when denominators approach zero.

    Market range Not applicable (purely numerical safeguard).

    0.000001
    Numerical stability constant (modeling convention)

  • Converts hourly flows and loads to annual totals via capacity factor.

    Market range Fixed (8760).

    8760h/year
    Calendar constant

  • Converts percentage inputs (0–100) to fractions (0–1) for calculations.

    Market range Fixed (0.01).

    0.01fraction/%
    Unit conversion constant

  • Converts fractions to percent and supports percent-based reporting.

    Market range Fixed (100).

    100
    Unit scaling constant

  • Converts between kWh and MWh for energy and electricity billing units.

    Market range Fixed (1000).

    1000kWh/MWh
    Unit conversion constant

  • Converts kg to metric tonnes for CO2 reporting.

    Market range Fixed (1000).

    1000kg/t
    Unit conversion constant

  • Used to convert methane volumetric flows (Nm3) to mass flows (kg) at normal conditions.

    0.714kg/Nm3
    Ideal-gas-based normal density approximation

  • Used to convert CO2 volumetric flows (Nm3) to mass flows (kg) at normal conditions.

    1.964kg/Nm3
    Ideal-gas-based normal density approximation

  • Used to estimate biomethane energy output from methane volumetric flow and CH4 fraction.

    9.97kWh/Nm3
    Methane lower heating value at normal conditions (typical)

  • Supports estimating the number of parallel trains at screening stage.

    500Nm3/h
    Typical modularization assumption

  • Defines the reference capacity for specific CAPEX scaling curves.

    500Nm3/h
    Scaling reference point (model convention)

  • Prevents unrealistically low specific CAPEX at very large scale in the screening model.

    Market range Order-of-magnitude safeguard (not a market quote).

    300EUR/(Nm3/h)
    Clamp bound for screening stability

  • Prevents unrealistically high specific CAPEX at very small scale in the screening model.

    Market range Order-of-magnitude safeguard (not a market quote).

    5000EUR/(Nm3/h)
    Clamp bound for screening stability

  • Prevents fixed O&M from falling below plausible levels for process plants.

    0.02ratio
    Clamp bound for fixed O&M fraction

  • Caps fixed O&M fraction at a conservative upper screening value.

    0.1ratio
    Clamp bound for fixed O&M fraction

  • Represents an indicative installed specific CAPEX at the reference capacity for water scrubbing.

    1200EUR/(Nm3/h)
    Screening reference CAPEX coefficient

  • Indicative installed specific CAPEX at the reference capacity for PSA upgrading.

    1300EUR/(Nm3/h)
    Screening reference CAPEX coefficient

  • Indicative installed specific CAPEX at the reference capacity for membrane upgrading (typical multi-stage design).

    900EUR/(Nm3/h)
    Screening reference CAPEX coefficient

  • Indicative installed specific CAPEX at the reference capacity for chemical scrubbing (amine).

    1500EUR/(Nm3/h)
    Screening reference CAPEX coefficient

  • Represents typical sub-linear scaling of total CAPEX with capacity for process skids.

    0.65
    Economies-of-scale exponent (screening)

  • Slightly higher scaling exponent assumed for PSA systems due to vessel/valve complexity.

    0.7
    Economies-of-scale exponent (screening)

  • Membrane skids can be modular; screening exponent reflects stronger economies at larger scale.

    0.6
    Economies-of-scale exponent (screening)

  • Chemical absorption/stripping columns and heat integration may scale somewhat closer to linear than skid-only systems.

    0.75
    Economies-of-scale exponent (screening)

  • Represents annual fixed O&M (labor, maintenance, spares) as fraction of CAPEX for water scrubbing.

    0.04ratio
    Fixed O&M fraction (screening)

  • Slightly higher fixed O&M for PSA due to valves, adsorbent changeout, and cycling maintenance.

    0.05ratio
    Fixed O&M fraction (screening)

  • Represents maintenance and periodic membrane element replacement at screening level.

    0.04ratio
    Fixed O&M fraction (screening)

  • Higher fixed O&M for chemical scrubbing due to solvent management and thermal equipment maintenance.

    0.06ratio
    Fixed O&M fraction (screening)

  • Reflects mild economies of scale in fixed O&M as plants get larger.

    Market range -0.15 to 0.00

    -0.05
    O&M scaling exponent (screening)

  • Same mild economies of scale assumption for PSA fixed O&M fraction.

    Market range -0.15 to 0.00

    -0.05
    O&M scaling exponent (screening)

  • Same mild economies of scale assumption for membrane systems.

    Market range -0.15 to 0.00

    -0.05
    O&M scaling exponent (screening)

  • Same mild economies of scale assumption for chemical scrubbing.

    Market range -0.15 to 0.00

    -0.05
    O&M scaling exponent (screening)

  • Representative electricity use for water scrubbing including compression to typical upgrading pressures.

    0.23kWh/Nm3
    Typical electricity intensity (screening)

  • Representative electricity use for PSA upgrading.

    0.25kWh/Nm3
    Typical electricity intensity (screening)

  • Representative electricity use for multi-stage membrane upgrading at moderate pressure.

    0.2kWh/Nm3
    Typical electricity intensity (screening)

  • Electricity for chemical scrubbing is often lower than PSA/water scrubbing; note that thermal energy is excluded in this simplified electricity-only model.

    0.12kWh/Nm3
    Typical electricity intensity (screening)

  • Represents auxiliary electricity for a simplified methane slip oxidation/handling unit.

    0.02kWh/Nm3
    Simplified adder for off-gas treatment

  • Captures screening-level pretreatment consumables/maintenance (e.g., simple drying, basic desulfurization cost proxy) as a variable cost per Nm3 raw biogas.

    0.01EUR/Nm3
    Simplified pretreatment OPEX coefficient

  • Adds a screening percentage of base CAPEX to represent methane slip treatment equipment.

    0.1ratio
    Simplified CAPEX adder for optional off-gas treatment

Sources

1 external source

  • upgrading_rz_low_final.pdf

Equipment

1 product in the catalog can be modelled with this calculator.

Bright Renewables

  • PurePac Compact100–750 Nm3/hCanonical model