“Introduction to Green Hydrogen” (2024), by Shannon Wachter Boettcher. Energy research paper. Original abstract below, unchanged. A free PDF is available.

Introduction to Green Hydrogen

Shannon Wachter Boettcher · December 11, 2024 · Energy

Abstract

Green hydrogen, produced through water electrolysis powered by renewable energy, is an essential component of future global energy systems.Green hydrogen is produced through water electrolysis powered by renewable energy sources, such as wind, solar, or hydropower, or possibly nuclear energy, resulting in low carbon emissions.1 While the CO₂ equivalent per kilogram of hydrogen produced (kgCO₂e/kgH₂) depends on many factors and requires a lifecycle analysis to assess.The U.S. Department of Energy's Section 45V tax credit targets green hydrogen at below 0.45 kgCO₂e/kgH₂.2 This requires minimizing emissions throughout the entire production process, including electricity use and upstream activities.These emissions are much lower than "gray" hydrogen from reforming natural gas (CH 4 + 2H 2 O → CO 2 + 4H 2 ) with ~10 kgCO₂e/kgH₂ and "blue" hydrogen using natural gas with carbon capture and ~4 kgCO₂e/kgH₂.3

Free PDF DOI: 10.1021/acs.chemrev.4c00787