Guest Contributor: Dr. Mani Vadari
There’s a lot of talk of the promise of hydrogen swirling around our industry today. As we move through the energy transition, we should look at all potential technologies and options to help us decarbonize. So, what’s up with the sensation surrounding hydrogen? How did it go from obscurity to the wonder solution of the 2020s?
Yes, hydrogen is a colorless gas, but it is increasingly referred to by a color to signify how ‘clean’ it is. Here’s the spectrum and a brief description.
- White hydrogen: the byproduct of industrial processes such as chloralkali electrolysis
- Grey hydrogen: produced from natural gas, which emits dioxide
- Brown hydrogen: produced from gasifying fossil fuels such as coal/petcoke, which emits carbon dioxide
- Green hydrogen: produced from the electrolysis of water powered by renewable energy
- Blue hydrogen: produced from reforming natural gas (or other fossil fuels) with carbon capture
- Yellow hydrogen: produced from the electrolysis of water using grid energy
- Purple hydrogen: produced though using nuclear power and heat through combined chemo thermal electrolysis splitting of water
- Pink hydrogen: produced through electrolysis of water by using electricity from a nuclear power plant.
- Red hydrogen: produced through the high-temperature catalytic splitting of water using nuclear power thermal as an energy source.
- Turquoise hydrogen: produced from natural gas using methane pyrolysis with carbon capture
- And, there is one more option (which hasn’t been given a color yet) – of mining for hydrogen.
Hydrogen is indeed the simplest and most abundant element in the universe, but it needs to be extracted from other elements to be used in gas form. It’s used extensively for industrial applications, but less than 1% of global hydrogen is derived from renewable energy. According to GreenTech Media (now Wood Mackenzie), in 2019, around 99 percent of the roughly 130 million tons of hydrogen a year used for industrial processes — mostly oil refining and ammonia production — was made using coal or lignite gasification processes, or steam methane reformation.
It’s not exactly efficient – yet
The round-trip efficiency of hydrogen measured by calculating the energy lost by converting electricity to hydrogen and back again to electricity is between 18-46%. The question that needs to be asked is, “Why would someone use electricity to make hydrogen and then convert it back to electricity at a 60-80% loss in energy?” True, you can make it more efficient by making hydrogen on-site, but then you have to bear the significant cost of electrolysis plants. In comparison, the typical loss in the U.S. from transferring electricity over wires is just 5%, so you still have 95% left.
It’s got green potential
The common argument made is that we should use excess renewable energy to produce hydrogen because, if not, this energy would be lost anyway. There is an inherent fallacy in this argument which is all about excess renewable energy. What is this about? Why do we have excess renewable energy?
My thought is that if the excess renewable energy is temporary in nature, then it will not be worth it to set up a hydrogen plant to use this excess renewable energy for hydrogen production. If the excess is long-lasting or permanent, would someone not try to create a business need to take advantage of it – someone with a better use of the energy than the 18-46% round-trip conversion that is being promised by hydrogen?
It’s part of the solution
The point of my musings is not about whether hydrogen is the answer to decarbonization or not. I believe hydrogen should and must have a place in our decarbonized future. However, to be a solid contender, we need to figure out how to produce hydrogen more efficiently since the present mechanisms of producing hydrogen will not sustain. We need newer mechanisms to produce hydrogen which would significantly increase the round-trip efficiency to greater than 70-80%. And we also need mechanisms to store and transport hydrogen so that it is available when and where it is needed.
Bottom Line: Until we are able to generate much more renewable energy and take greater advantage of storage technologies, doesn’t it make more sense to use all renewable energy directly as electricity for end uses (heat, transport, etc.), rather than suffer the losses that currently come with green hydrogen production?
Dr. Mani Vadari is President and founder of Modern Grid Solutions, a global energy consulting firm specializing in delivering strategic services to utilities and vendors seeking deep subject matter expertise in setting the business and technical direction to develop the next-generation electric/energy system. Dr. Vadari is a well-known keynote speaker and regularly contributes to several industry publications. His most recent book “Smart Grid Redefined: Transformation of the Electric Utility” was released to strong reviews from industry and academia. His first book “Electric System Operations – Evolving to the Modern Grid” is in its second edition and is still being used as a textbook at several universities.