Life cycle hydrogen production

The category at business/processes/production/hydrogen/production provides a methodology for calculating greenhouse gas emissions associated with the production of hydrogen. The methodology is based on a default emissions factors for several stages in the life-cycle of hydrogen production. This methodology is sourced from the Life Cycle Assessment of Hydrogen Production via Natural Gas Steam Reforming report of the US Department of Energy's National Renewable Energy Laboratory. This report and the emissions factors included are referenced in the EPA's guidelines for mandatory reporting of greenhouse gas emissions associated with hydrogen production, although they do not formally specify this as a recommended methodology.

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How to use this category

Selecting an emissions scenario

To use this category, specify a process using the process drill choices.

• 'full life cycle': returns per unit emissions for the entire life cycle

• 'construction and decommissioning': returns per unit emissions for the plant construction and decommissioning phase

• 'natural gas production and transport': returns per unit emissions for the production and distribution of the natural gas feedstock

• 'electricity generation': returns per unit emissions for the on-site generation of electricity

• 'plant operation': returns per unit emissions from plant operation (used to derive annual sector emissions statistics in the EPA's documentation

• 'avoided operations': returns per unit emissions avoided through the export of steam to other facilities

Specifying activity data

Next, specify the quantity of hydrogen produced using the mass profile item value.

Results and calculation

The quantities returned represent the greenhouse gas emissions associated with that quantity of hydrogen associated the process specified. The following quantities are returned, as follows:

• CO2: absolute quantity of CO₂ emissions for the quantity specified
• CH4: absolute quantity of CH₄ emissions for the quantity specified
• N2O: absolute quantity of N₂O emissions for the quantity specified
• CO2e: CO₂e emissions (absolute emissions converted using the appropriate global warming potential)