Hydrogen
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Before You Watch Our Lecture
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Our Lecture
Watch the Stanford course lecture.
Additional Resources
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Fast Facts About
Hydrogen
Principal Energy Uses: Electricity, Transportation
Hydrogen is a versatile energy currency that can be produced from fossil fuels or water and that also occurs naturally in rocks underground. Hydrogen has very low energy density by volume but is extremely energy dense by weight. Although it is currently used primarily as a feedstock for oil refining, chemicals, and fertilizers, hydrogen shows promise as a clean fuel for heavy-duty transportation, steel-making, heating, and energy storage. Hydrogen is often referred to as the “Swiss Army knife of decarbonization”, because it has potential in hard to decarbonize applications; however, it is still nascent and a lot needs to happen (regulatory, tech innovation, infrastructure build-out) before it can contribute to decarbonization.
Today, the vast majority of produced hydrogen is created from fossil fuels, but renewable hydrogen can be created through electrolysis, the process of using electricity to create hydrogen from water. Electrolysis is more expensive than fossil fuel hydrogen and other fuels, but the relative costs are rapidly decreasing due to technological innovation, government subsidies, investment activity, and commercialization.
Geologic hydrogen, hydrogen that occurs naturally in rocks underground, is difficult to detect and has long been overlooked. However, breakthroughs in recent years have generated significant interest and investment in the prospect of geologic hydrogen as an economically viable clean energy source.
Current Status
Categories of Hydrogen*
Brown Hydrogen
Hydrogen produced from coal gasification
Grey Hydrogen
Hydrogen produced from steam methane reforming, a process which converts natural gas into hydrogen and CO2
Yellow Hydrogen
Hydrogen produced from grid electricity through electrolysis
Pink Hydrogen
Hydrogen produced from nuclear energy through electrolysis
*All hydrogen is the same. Colors are assigned based on the environmental impact of how the hydrogen was produced. The colors above are listed in order of their environmental impact. (brown is worst; green, and potentially white/gold, are best).
The Future
Potential Significant Markets
- Steel production
- Trucks, planes, and ships
- Long term energy storage
- Building and industrial heating
- Clean chemicals
Drivers
- High energy density by weight
- Can be a low to no carbon fuel
- Strong policy support and subsidies for hydrogen production
- Can be paired with renewables to produce zero carbon fuels
- No air emissions when using / burning hydrogen; only byproduct is water
- Potential for long term energy storage
- Potential to decarbonize steel production
- Potential to replace carbon fuels in transportation
- Most abundant element on the planet
- Reduces reliance on imports of fuels
Before You Watch Our Lecture on
Hydrogen
We assign videos and readings to our Stanford students as pre-work for each lecture to help contextualize the lecture content. We strongly encourage you to review the Essential videos and readings below before watching our lecture on Hydrogen. Include selections from the Optional and Useful list based on your interests and available time.
Essential
- Hydrogen 101. Student Energy. May 18, 2015. (3 min)
Quick overview of what hydrogen is and the two main ways we make it (since it’s an energy carrier, not an energy resource, we have to make it). - Your Definitive Guide to Understanding Hydrogen. Cipher. February 28, 2024. (1 page)
A "cheat sheet" for what hydrogen is and why everybody's talking about it now. - The Truth About Hydrogen. DW Planet A. February 25, 2022. (12 min)
Explores the drivers and barriers to hydrogen contributing to a decarbonized future. - Can Hydrogen Help the World Reach Net Zero?. Financial Times. June 13, 2023. (24 min)
Explores the role hydrogen could play in the global push for net zero emissions. - How Does a Fuel Cell Work?. Naked Science Scrapbook. October 7, 2011. (4 min)
Simple demonstration on how fuel cells work.
Optional and Useful
- A Treasure Hunt For Underground Hydrogen Is On. Cipher. March 6, 2024. (3 pages)
A look at the recent and rapidly growing interest in searching for geologic hydrogen. - How Much Clean Energy Does It Take To Make Green Steel?. Canary Media. May 22, 2024. (4 pages)
Examines U.S. green steel projects using clean hydrogen. - One Year In, Us Clean Hydrogen Hubs Face Questions — And Have Few Answers. Canary Media. October 16, 2024. (5 pages)
Evaluates the progress and transparency of the $7B U.S. clean hydrogen hubs initiative. - World’s First Entirely Hydrogen-Powered Ferry Welcomes Passengers on July 19 in San Francisco Bay. San Francisco Bay Ferry. July 12, 2024. (2 pages)
Announces the launch of the world’s first commercial passenger ferry powered 100% by hydrogen fuel cells. - NCPA LEC Hydrogen Project. NCPA Power. November 16, 2023. (7 min)
Overview of a Northern California Power Agency project to use green hydrogen by burning it inside of natural gas turbines. - Unique Time in History for Energy and Hydrogen | Dr. Arun Majumdar | Episode 10. Stanford Hydrogen Innovators Podcast. August 2023. (37 min)
Dr. Majumdar's perspective on where hydrogen should and should not play a role in our energy transition. - What is Hydrogen Energy?. McKinsey & Company. October 2, 2024. (4 pages)
Explains what hydrogen energy is and its potential role in decarbonizing major industries. - What Is Green Hydrogen and Will It Power the Future?. CNBC. December 3, 2020. (15 min)
View interviews of experts and policy makers on how hydrogen fits into the future clean energy space.
Our Lecture on
Hydrogen
This is our Stanford University Understand Energy course lecture on hydrogen. We strongly encourage you to watch the full lecture to understand the potential roles of hydrogen in achieving net zero and to be able to put this complex topic into context. For a complete learning experience, we also encourage you to watch / read the Essential videos and readings we assign to our students before watching the lecture.

Presented by: Xiaolin Zheng, PhD; Professor, Mechanical Engineering, Energy Science Engineering; Senior Fellow, Precourt Institute for Energy; Professor, by Courtesy, Materials Science and Engineering, Stanford University
Recorded on: November 6, 2023 Duration: 34 minutes
Table of Contents
(Clicking on a timestamp will take you to YouTube.)
00:00 Introduction & Overview of Hydrogen's Roles for Reducing Greenhouse Gas Emissions
16:08 Hydrogen Production
25:31 Hydrogen Storage and Transportation
31:57 Hydrogen Utilization
33:33 Summary
Lecture slides available upon request.
Additional Resources About
Hydrogen
Government and International Organizations
- International Energy Agency (IEA) Hydrogen
- US Department of Energy (DOE) Hydrogen Program
- US Energy Information Administration (EIA) Hydrogen Explained
- US Hydrogen and Fuel Cell Technologies Office (HFTO)
- US Office of Energy Efficiency & Renewable Energy (EERE) Clean Hydrogen Electrolysis Program
- US Alternative Fuels Data Center (AFDC) Hydrogen Fueling Station Locations
- California Energy Commission (CEC) Hydrogen Vehicles & Refueling Infrastructure
Fast Facts Sources
- Geologic Hydrogen: Cipher. A Treasure Hunt For Underground Hydrogen Is On. March 6, 2024.
- Hydrogen Sources (World 2022): International Energy Agency (IEA). Tracking Hydrogen: Energy. 2023.
- Hydrogen Uses (World 2022): International Energy Agency (IEA). Global Hydrogen Demand by Sector in the Net Zero Scenario, 2020-2030. September 2023.
- Change in Global Demand (2019-2022): International Energy Agency (IEA). Global Hydrogen Demand by Sector in the Net Zero Scenario, 2020-2030. September 2023.
- Growth of VC Investment (World 2017-2022): Pitchbook. VC and PE Investing in Hydrogen Broke Records in 2022. December 2022