Electrolyzer Calculator

Avoltium Ultimate Electrolyzer Sizing Engine

Advanced BOP Engineering Sizing

The definitive mathematical engine for Green Hydrogen Balance of Plant sizing. Execute rigorous calculations for power capacity, CAPEX, and multi-stage water treatment.

1 System Parameters
How much Hydrogen gas must the facility produce daily?
Typical Plant Scales:
Pilot/Mobility: 100 – 500 kg/day (approx. 1,112 – 5,560 Nm³/day)
Commercial/Industrial: 1,000 – 5,000 kg/day (approx. 11,120 – 55,600 Nm³/day)
Gigawatt Scale (Export): 100,000+ kg/day (approx. 1.1M+ Nm³/day)
Total uptime. Grid tied is usually 24h. Solar/Wind systems typically run 8-12 hours based on capacity factor.
Select the core stack technology to load baseline efficiencies and specific energy constraints.
The raw electrical energy required by the stack to split water into 1 unit of H2. (Theoretical LHV minimum is 39.4 kWh/kg).
Reverse Osmosis water purification rejects water as brine. 75% means 25% is wasted during purification.
Capital Expenditure of the stack and primary BOP per kilowatt of capacity.
2 Mathematical Breakdown
Step A: Mass Standardization
All thermodynamic calculations require standard mass. If volumetric flow (Nm³ or scf) is provided, we divide by the standard density of Hydrogen gas (0.08988 kg/Nm³).
Step B: Electrical Energy & Power Sizing
Total daily energy (kWh) is calculated via Specific Energy. To size the rectifiers, transformers, and grid connection (MW), we divide by the Operating Window to find steady-state power draw.
Step C: Granular Water Balance (UPW + Cooling)
1. Process Water (Stoichiometric): Exact chemical requirement (~8.92 L/kg).
2. Raw RO Feed Water: Factoring in the Reverse Osmosis reject rate.
3. Cooling Water Makeup: Energy exceeding the LHV (39.4 kWh/kg) is lost as heat. Assuming wet cooling towers, ~0.5 Liters of water evaporates per kWh of heat rejected.
Minimum BOP Power
0 MW
0 kW
Total Daily Raw Water
0 L
RO Feed + Cooling
Estimated Stack CAPEX
$0M
Order of Magnitude

Engineering Standards & Citations

  • Stoichiometric Demand (8.92 L/kg): Based on the molar mass ratio of H₂O (18.015 g/mol) to H₂ (2.016 g/mol) equating to 8.936 kg water per kg hydrogen. The 8.92 L/kg standard incorporates typical vapor phase dynamics without vent loss (Ref: IRENA 2020, Green Hydrogen Cost Reduction, p. 54).
  • Thermodynamic Baselines: Calculations assume a Lower Heating Value (LHV) for Hydrogen of 33.33 kWh/kg and an electrolysis thermoneutral voltage equivalent of 39.4 kWh/kg (HHV) (Ref: DOE Hydrogen and Fuel Cells Program Record, Table 2).
  • Cooling Evaporation Loss: Waste heat is calculated as (Applied Specific Energy – LHV). Evaporation rates assume standard wet cooling towers rejecting latent heat of vaporization at approx 0.5 – 0.6 Liters per kWh thermal (Ref: ASHRAE Handbook – HVAC Systems and Equipment, Ch. 40 Cooling Towers).
  • RO Recovery Rates: Assumes standard commercial Reverse Osmosis limitations: 75% for municipal low-TDS water, 60% for brackish groundwater, and 40% for seawater desalination systems (Ref: EPA Guidelines for Water Reuse, Section 4.3).

Require a Certified FEED Study?

This mathematical engine provides highly accurate baseline estimates. However, real-world deployment requires modeling rectifier harmonic losses, exact thermal management loops, and site-specific water mineralogy.

Consult Avoltium Engineering