energy_mass_balancecostinghydrogen
Screening-stage ATR hydrogen calculator with annual/daily mass & energy balance and CAPEX/OPEX to levelized cost of hydrogen (LCOH).
Design (full-load) hydrogen output at the plant battery limit. Used for CAPEX scaling and production calculations.
min 1000 · max 300000 · step 1000 · kg H2/day
Delivered natural gas price on an LHV energy basis.
Grid electricity price for imported power (e.g., ASU and auxiliaries).
Industrial make-up water cost (screening).
Real discount rate used for CRF-based annualization.
Levelized cost of hydrogen (LCOH)
Total annual cost divided by annual hydrogen production
Installed plant cost (installed CAPEX)
Equipment purchase cost × installation factor (screening)
Total OPEX (annual)
Fixed O&M + feedstock and utility costs
Total equipment purchase cost (EPC, equipment-only)
Excludes installation, indirects, and owner’s costs
Equipment cost — H2 purification (e.g., PSA)
Purification and product handling (equipment-only)
Equipment cost — ATR reforming island
Reformer/reactor/heat recovery block (equipment-only)
Equipment cost — ASU / oxygen supply
Major subsystem bucket (equipment-only)
Equipment cost — Balance of plant (BoP) & utilities
Water/steam systems, cooling, power distribution, etc. (equipment-only)
Hydrogen production (annual)
Annualized from nameplate capacity and capacity factor
Hydrogen production (average day)
Annual production divided by 365
Natural gas energy input (annual)
Effective specific consumption × annual H2 production
Natural gas energy input (average day)
Annual NG energy divided by 365
Electricity consumption (annual)
Includes ASU and auxiliaries via a kWh/kg intensity factor
Water consumption (annual)
Process/boiler feed make-up via a m3/kg intensity factor
CO2 produced (annual)
Uncaptured CO2 stream for no-CCS ATR
CO2 produced (average day)
Annual CO2 divided by 365
Calculator context
This calculator provides a screening (pre-feasibility) estimate of an autothermal reforming (ATR) natural-gas-to-hydrogen plant’s mass/energy balance and cost metrics, including equipment purchase cost, installed plant cost, annual OPEX, and levelized cost of hydrogen (LCOH). It is conceptually aligned with the NETL comparative assessment of commercial fossil-based hydrogen technologies (NETL, 2022) and uses standard techno-economic practices commonly seen in IEA/IRENA/NREL-style models. Regional scope is global (no region-specific cost index is applied).
The model converts a user-provided nameplate hydrogen capacity (kg/day) into annualized production using a capacity-factor framework, then applies intensity factors (feed/utility/CO2 per kg H2) with a part-load penalty, and finally computes costs using scaled specific CAPEX and fixed/variable OPEX.
Key formulas (variables defined in-line):
Primary reference: NETL (2022) technology comparison report; scaling conventions and CRF are consistent with common practice in IEA/IRENA/NREL techno-economic analyses.
32 assumptions used in the calculations
Prevents divide-by-zero in guarded denominators.
Market range Not applicable
Used to convert capacity factor to annual load hours.
Market range 8760 (non-leap year basis)
Converts kg/day to kg/h for load-hour annualization.
Market range 24
Used for average daily quantities from annual totals.
Market range 365 (screening basis)
Converts kWh to MWh.
Market range 1000
Converts MJ to GJ in LHV computations.
Market range 1000
Converts kg to metric tonnes.
Market range 1000
Avoids inline numeric literals in DSL expressions.
Market range 1
Caps part-load consumption penalty to avoid unrealistic blow-ups at lower CFs.
Represents increased specific consumption as capacity factor decreases (availability/part-load effects).
Represents natural gas LHV energy input per kg H2 produced at full load (includes process fuel and reforming feed energy on a net basis).
Represents imported electricity demand dominated by ASU power and auxiliaries at full load.
Represents make-up water for steam generation and cooling system losses at full load.
Represents process CO2 produced per kg H2 for fossil reforming pathways without capture.
Hydrogen lower heating value used for efficiency reporting.
Market range 0.12
Defines the reference scale for CAPEX and O&M scaling curves.
Represents total equipment purchase cost normalized by capacity at the reference size.
Power-law scaling exponent for equipment CAPEX vs capacity.
Prevents unrealistic low specific costs at very large scales within a simplified scaling model.
Prevents unrealistic high specific costs at very small scales within a simplified scaling model.
Converts equipment purchase cost to installed plant cost (installed scope; excludes owner’s costs unless included by convention).
Approximate fraction of equipment purchase cost attributed to the ATR reforming island and heat recovery.
Approximate fraction of equipment purchase cost attributed to oxygen supply (ASU) for ATR.
Approximate fraction of equipment purchase cost attributed to purification (e.g., PSA) and product conditioning.
Approximate fraction of equipment purchase cost attributed to balance-of-plant utilities and offsites.
Represents labor, maintenance, overheads and routine replacements as a fraction of installed plant cost per year.
Allows fixed O&M fraction to slightly decrease with plant scale.
Prevents unrealistically low fixed O&M at very large scales.
Prevents unrealistically high fixed O&M at very small scales within a simplified model.
Capacity factor is fixed at 95% as per instruction.
Market range 0.95
Project lifetime is fixed at 15 years as per instruction.
Market range 15
Converts MWh to GJ for price normalization.
Market range 3.6
