How hydrogen can reduce natural gas CO2 emissions

This article was published by the Canada Energy Regulator on Sept. 23, 2020.

Hydrogen is becoming increasingly important in global green energy strategies, and could play a significant role in Canada’s own carbon-emission reduction goals.

One potential use for hydrogen gaining traction in Canada, is blending it into natural gas streams to create a less carbon-intensive alternative to pure natural gas. ATCO’s recently announced pilot project will use funding from Emissions Reduction Alberta’s Natural Gas Challenge to blend up to 5 per cent hydrogen into natural gas distribution networks in Fort Saskatchewan, Alberta. The pilot project is planning to begin in Q1 2021.

There are 3 main methods used to produce hydrogen:

1. Grey hydrogen uses an industrial process called ‘steam methane reforming’, which uses high temperature steam to separate hydrogen from methane–the main component of natural gas.
2. Blue hydrogen uses the same method as grey hydrogen, except it captures and stores the carbon dioxide (CO₂) emissions resulting from the process.
3. Green hydrogen utilizes renewable electricity and a process called electrolysis (passing an electric current through water) to separate and extract hydrogen molecules from water.

Figure 1. CO₂ Emissions from the Combustion of 3 Types of Hydrogen

Grey hydrogen is the most carbon-intensive type of hydrogen; nearly comparable to coal-fired electricity, at approximately 90 grams of CO₂ equivalent per megajoule (g CO₂e/MJ). Blue hydrogen provides significant reductions in emission estimates at 22 g CO₂e/MJ, and green hydrogen has the potential for zero emissions if the electricity used in the electrolysis is emissions-free.

Initially, the Alberta pilot project will use grey hydrogen. Moving forward, the project could rely on blue hydrogen, if the CO₂ from the hydrogen production process is captured using carbon capture and storage technology.