Hydrogen
Hydrogen as a fuel, especially for powering vehicles, has potential, but it is hard to separate out the real promise from hype.
Hydrogen burns clean, releasing only water vapor and no GHG. There are hydrogen-powered vehicles out there already.
To be useful it would require a lot of resources and infrastructure to scale up. The hydrogen fuel has to be transported and stored safely and be available. California, for example, is planning on increasing the infrastructure for hydrogen-powered vehicles. One idea that would need less infrastructure is to use hydrogen for mass transit, for example buses in cities and suburbs, where they would be refueled in a central location.
The source material for hydrogen is water. Whether to use fresh water, a scarce resource during droughts, or to alter the ecology of sources of salt water and performing extra energy-requiring steps to remove the salt, isn’t a trivial concern.
The benefit is that no greenhouse gases are produced when hydrogen is used as a fuel. However, how “clean” hydrogen production is depends on whether or not clean energy sources are used to run the reaction of splitting the water into hydrogen and oxygen (which takes energy).
“Brown or black” hydrogen is produced from energy derived from coal.
“Grey” hydrogen uses methane (natural gas) and generates CO2.
“Blue” hydrogen at least captures the CO2 generated using methane.
The best is “green” hydrogen that uses renewable energy sources to power the production of hydrogen for fuel.
White hydrogen is hydrogen in natural deposits deep in the earth. While some large deposits have been found, it is not clear just how many such deposits there are that are accessible, what energy and resources it would take to extract the hydrogen, and whether it can it be obtained economically. It may take way too long to figure out, decades or more, but there is a lot of interest in this (including by fossil fuel companies whose technology and expertise can be adapted to exploit white hydrogen).
Gold hydrogen is formed by microbial action in oil and gas wells.
While white and gold hydrogen do not need energy to create the hydrogen from water, it will take energy to extract and transport the hydrogen.
There are bipartisan efforts to use provisions of the Inflation Reduction Act (see the August 16, 2022 news post) to make hydrogen fuels more affordable in the United States. The devil of how the tax incentives will work is in the details, which are still being worked out.
Hydrogen is currently used primarily by the chemical industry. Even if not practical for transportation, green hydrogen would be a boon. A concern is that the hype around hydrogen is a form of greenwashing by the chemical industry! For now, it is very expensive to produce green hydrogen and it isn’t clear what role hydrogen powered vehicles may have given the energy used to produce and distribute hydrogen and upgrade the infrastructure to handle it.
Is Hydrogen a Viable Fuel Alternative?
Oct 16
I want to love hydrogen as a source of power for vehicles and industry. So far I can’t.
Let’s look a bit at hydrogen as a fuel.
The way we get hydrogen is by splitting water, H2O, into H and O. So, start with water, add energy, then hydrogen and oxygen are produced.
Hydrogen is a powerful source of energy. Basically, the energy that was put into separating water into oxygen and hydrogen is recovered in the reverse reaction. Add oxygen to hydrogen, you get water and energy, sometimes explosively: think the Hindenburg disaster. But despite using that alarmist picture for the post, in “small doses," hydrogen as it would be used in vehicles appears to be safer than gasoline if the vehicle is on fire. The hydrogen would likely escape, unlike gasoline. At least, that’s what they tell me (including sources I trust).
Importantly: no greenhouse gases are involved! (Spoiler alert: this isn’t really true in practice, as we will soon see.)
The raw material for obtaining hydrogen is water, which itself is a bit of a problem. We are over-using water, perhaps our most precious resource. However, producing hydrogen requires much less water than the fossil fuel industry currently uses for an equivalent amount of energy, and with less pollution to the water table (think fracking, for example). So far, so good.
The big problem with hydrogen from the climate change point of view is which source of energy you use to make it. It takes energy to break down water into hydrogen and oxygen. CO2 is, however, produced in producing the hydrogen using fossil fuels as the energy source!
Yes: for the most part currently that energy needed to produce hydrogen is obtained from fossil fuels!
A somewhat dated analysis by the Union of Concerned Scientists does point out that hydrogen fuel cell vehicles, even using natural gas as the energy source in production of the hydrogen, are better than gasoline-powered vehicles, but that is a very low bar.
Hydrogen can be combusted when it is used as an energy source, i.e., burned, much like gasoline, releasing energy that can be used in vehicles or industrial processes. That does produce nitrogen oxide pollutants, but not CO2.
But currently in vehicles hydrogen is primarily used in hydrogen fuel cells. When hydrogen is used in a vehicle’s hydrogen fuel cell, the reactions of hydrogen ions (protons) and electrons with oxygen power an electric motor without combustion.
The bottom line is that in the fuel cell the reaction is reversed: hydrogen and oxygen become water and (electrical) energy.
[Aside: For clinicians and those with backgrounds in biology, you might note that there is a rough analogy with the role of hydrogen ions/protons and electrons in the electron transport chain in mitochondria! Similar energy capturing reactions lead to a mechanical molecular response; the molecule literally spins like a motor, in ATPase.]
Now, there are other ways to produce hydrogen rather than using fossil fuels for an energy source. “Green hydrogen” is produced without the use of fossil fuels. Clean energy sources could be used (solar, wind, hydropower), but the Sierra Club concluded that this is an inefficient use of clean energy. However, in the book No Miracles Needed, Stanford engineering professor and environmental activist Mark Z. Jacobson points out some advantages of green hydrogen, and does consider that it may play a role in fighting climate change.
One advantage for hydrogen fuel cells may be that they are made with less need for difficult to source and obtain metals such as lithium and cobalt used in current lithium electric vehicle batteries. Hydrogen fuel cells use primarily platinum, which can be recycled.
Hydrogen-powered vehicles are already on the roads. An industry-funded site says that there were more than 72,000 hydrogen-powered vehicles on the road in 2022, up 40% from the previous year. Another industry site says that as of September 2023 there were at least 66 hydrogen fuel cell buses in operation in California. By the end of 2023 there are expected to be 47 on the streets of Paris.
The news that brings all this up: the Biden administration has announced 7 billion dollars for hydrogen hubs.
These hubs are necessary because it isn’t viable to ship hydrogen using tucks or trains or very long pipelines. That is a problem, but not the main concern from the point of view of climate change. The current proposals for hydrogen production use methane for the energy source to produce hydrogen.
Hmm, so much for clean energy and green hydrogen!
They are betting on carbon capture, but that has not been scaled up to anything like the degree needed, and it isn’t clear it can be.
I want hydrogen to save us, but even if you can scrub the CO2 from the smokestacks when you produce hydrogen, methane, a very powerful greenhouse gas that is used to power the process, will leak from pipelines and continues environmentally unfriendly practices like fracking.
Oil and gas companies love it, I suspect, however much they complain about the hurdles. Of course, they want special treatment. Pipeline companies and investors in pipelines love it as hydrogen will have to be piped from hubs to end-users.
“Biden's administration has set a target to increase clean hydrogen output to 10 million metric tons by 2030, and 50 million by 2050, up fivefold from today - and considers the fuel an ideal option for cutting emissions from tough-to-decarbonize industrial users like steel and cement.
“Environmentalists want the Treasury to require that the tax credits, worth up to $100 billion, only go to hydrogen producers that use new sources of clean electricity instead of tapping power already on the grid.
"’We need rigorous guardrails to ensure that U.S. hydrogen does not create an emissions mess, and that we are not subsidizing hydrogen that is clean in name only,’ said Rachel Fakhry, policy director for emerging technologies at the Natural Resources Defense Council.
Industry groups have rebuffed the idea, saying it would stifle investment. “
Yes, it comes down to the fuel industry bottom line.
Maybe in the greater scheme of things, $7 billion is a worthy investment, but that is not at all clear. I would rather that money be used elsewhere; if for hydrogen power, then for less biased research and development than I believe we will get from the fuel industry (and betting on carbon capture and storage to save us).
Yes, I want to love hydrogen, but so far I believe this $7 billion may be a gift to the fossil fuel industry with little to gain in the fight against climate change. Let’s see. Perhaps that will change.