Green Hydrogen Calculator

Green hydrogen is hydrogen produced by water electrolysis using renewable electricity. Under EU rules, it qualifies as a Renewable Fuel of Non-Biological Origin (RFNBO) when its lifecycle emissions are below 3.38 kg CO₂e per kg H₂ (28.2 gCO₂e/MJ), 70% lower than the fossil baseline of 94 gCO₂e/MJ.

Modern commercial electrolyser systems consume approximately 50 to 55 kWh per kg H₂ on a Lower Heating Value (LHV) basis. The theoretical minimum is 39.4 kWh/kg (HHV); the rest is lost to overpotentials, balance-of-plant power, and waste heat.

Alkaline (AWE) is the most mature, lowest-CAPEX, and best for baseload operation. PEM offers faster dynamic response and higher purity at higher CAPEX. SOEC reaches the highest electrical efficiency but requires steam at high temperature. AEM is emerging, combining alkaline economics with PEM-like dynamics, without platinum-group catalysts.

Stoichiometrically, 9 kg of water per kg of hydrogen. In practice, including water purification, commercial plants consume 10 to 11 L of demineralised water per kg H₂, and 20 to 30 L total when cooling water is included.

In 2024 to 2025, green hydrogen LCOH ranges from 3 to 9 USD/kg depending on region, with the most favourable sites (Middle East, Chile, North Africa) at the lower end. The IEA Net Zero scenario projects 2 to 4 USD/kg by 2030, but this requires sustained CAPEX and electricity-price reductions.

Renewable Fuels of Non-Biological Origin (RFNBO) is the EU classification for renewable hydrogen and hydrogen-derived fuels. Compliance requires that the lifecycle emissions are below 3.38 kg CO₂e/kg H₂, AND that the electricity used meets additionality, temporal correlation (hourly from 2030), and geographical correlation criteria.

Grey hydrogen comes from natural gas steam methane reforming, emitting 10 to 12 kg CO₂/kg H₂. Blue hydrogen adds carbon capture, reaching 1 to 4 kg CO₂/kg H₂. Green hydrogen comes from renewable electrolysis (0.4 to 2.7 kg CO₂/kg H₂). Pink hydrogen comes from nuclear-powered electrolysis (0.5 to 1.5 kg CO₂/kg H₂).

For grid electrolysis: SEC (about 52 kWh/kg) × grid emission factor + embodied emissions (about 1.5 kg/kg). On a 200 gCO₂/kWh grid, this gives about 11.9 kg CO₂/kg H₂, similar to grey hydrogen. On a 50 gCO₂/kWh grid (France, Norway), it gives 4.1 kg/kg. On a dedicated renewable, it is 1.5 to 2.5 kg/kg.

Capacity factor (CF) is the fraction of nameplate capacity actually used over a year. For grid-connected electrolysers, CF can reach 90+%. For renewable-coupled systems, CF typically follows the renewable resource: 15 to 30% for solar-only, 35 to 50% for wind-only, 50 to 70% for hybrid PV + wind.

A 1 MW alkaline system occupies roughly 80 to 150 m², plus auxiliary space for water treatment, electrical, and compression. PEM is more compact at 50 to 100 m²/MW. A modern containerised PEM 1 MW system fits in two to three standard 40-foot containers.

In European conditions (about 2,170 full load hours, IEA), 1 MWp of PV generates roughly 2,170 MWh per year. At a system SEC of 52 kWh/kg, this would produce about 42 tonnes of H₂ per year, equivalent to roughly a 0.3 MW electrolyser if perfectly coupled.

The tool checks the carbon-intensity threshold (3.38 kg CO₂e/kg H₂) and flags compliance. Full RFNBO certification additionally requires audited supply contracts for additionality, temporal correlation (monthly until end-2029, hourly from 2030), and geographical correlation, which the tool summarises but does not certify.