Green Hydrogen Production Calculator

Green hydrogen is produced via electrolysis powered exclusively by renewable energy, resulting in near-zero carbon emissions. Grey hydrogen comes from steam methane reforming (SMR) without carbon capture, while blue hydrogen also uses SMR but captures most of the CO₂. Green hydrogen is considered the cleanest pathway and is the focus of this calculator.

In practice, producing 1 kg of H₂ via electrolysis typically requires 50–70 kWh of electricity, depending on the electrolyzer technology and operating conditions. PEM systems commonly consume around 55 kWh/kg, while more mature alkaline systems may consume 60–70 kWh/kg. The specific electricity consumption field in this calculator lets you input your system's real value.

Electrolyzer efficiency represents how much of the electrical energy input is converted into chemical energy stored in hydrogen (based on HHV). A 70% efficient electrolyzer converts 70% of input power into usable H₂ energy. Higher efficiency means more hydrogen produced per unit of electricity consumed, directly increasing your daily kg output.

Electrolysis requires approximately 9 litres of pure water to produce 1 kg of hydrogen (based on the stoichiometric ratio of H₂O → H₂ + ½O₂). In real systems, accounting for purification and process losses, the requirement is typically 10–15 litres per kg. This calculator uses 9 L/kg as the baseline stoichiometric value.

Solar PV, wind, and hydropower are the most commonly used sources. Wind and hydropower tend to offer higher capacity factors (more consistent output), while solar PV has rapidly falling costs. The ideal source depends on your geographic location, available land, and project economics. This calculator lets you select your source to tailor the CO₂ avoidance calculation.

The Higher Heating Value (HHV) of hydrogen is approximately 39.4 kWh per kg (or 141.8 MJ/kg). This represents the total energy released when hydrogen is burned and water vapour is condensed back to liquid. The Lower Heating Value (LHV) is about 33.3 kWh/kg, excluding the latent heat of vaporisation. This calculator uses the HHV for energy content outputs.

CO₂ avoidance is calculated by multiplying the total renewable electricity consumed by the grid's carbon emission factor (kg CO₂/kWh). If your electrolyzer uses power that would otherwise have been supplied by the grid, displacing that grid electricity reduces emissions. You can enter your regional grid emission factor to get a location-specific avoidance estimate.

PEM (Proton Exchange Membrane) electrolyzers offer fast response, high purity H₂, and compact size — ideal for variable renewable inputs. Alkaline electrolyzers are mature, lower cost, and suited for steady baseload operation. SOEC (Solid Oxide Electrolyzer Cells) operate at high temperatures and can achieve the highest efficiencies, but are still largely in development. Your choice affects specific energy consumption and system design.