|Hydrogen has advantages as a fuel, including its gasoline-like portability. But key to its importance is its climate friendliness. Above, a hydrogen vehicle at a fueling station in Irvine, Calif. in 2017. Photo: National Renewable Energy Lab/Dennis Schroeder, Flickr Creative Commons. Click to enlarge.|
Backgrounder: Hydrogen Rainbow May Dazzle, But Journalists Should Eye It Warily
By Joseph A. Davis
Hydrogen energy will probably not solve the climate crisis. But we are hearing a lot of hype about its energy these days, so environmental journalists would be wise to learn more.
Let’s start with the basics. When hydrogen burns (i.e., combines with oxygen), it produces energy (i.e., heat) and water vapor (i.e., H2O). In that sense, it is clean.
And hydrogen does have some advantages as a fuel. It is portable, like gasoline, so you can put it in a tank and drive your internal-combustion car. Hydrogen can also power fuel cells that can power a car’s electric motor.
One disadvantage, however, may be safety. Hydrogen can burn explosively — remember the Hindenburg? Safe handling and transport of hydrogen may require freezing or compression.
But the key concern? Its source. Hydrogen is one of the most abundant elements in the universe, but it does not occur naturally in a pure form on Earth or in Earth’s atmosphere. You can’t mine it. You have to make it.
Making hydrogen takes energy. So, although
we are often encouraged by its promoters to
think of it as a fuel, it is more accurately
considered a way to store energy.
And making hydrogen takes energy. So, although we are often encouraged by its promoters to think of it as a fuel, it is more accurately considered a way to store energy. From a climate perspective, then, the key question is where we get the energy to make hydrogen.
The hydrogen color game
Hydrogen is often called “the future,” without much solid evidence. There are lots of start-ups and entrepreneurs claiming that hydrogen energy is the cure to what ails us and the greatest thing since sliced bread.
It’s true that if the energy source for hydrogen production is “clean” (that is, it doesn’t produce greenhouse gas emissions), then hydrogen may have some use in addressing climate. In practice, this would mean wind or solar photovoltaic electric power.
Let’s call hydrogen made this way “green” hydrogen.
But the color metaphor is the start of potential confusion — there is also blue hydrogen, gray hydrogen, brown hydrogen and even pink hydrogen.
They are not all the same. It’s all a sort of thimblerig game, so watch the pea (which is climate change) not the shell.
A bit of basic science
It helps to back up and consider the few major ways in which most industrial hydrogen is manufactured.
One common way — you see it in high school chemistry labs — is electrolysis. When you pass an electric current through water (which is made of two atoms of hydrogen and one atom of oxygen), the water molecules separate into the two pure elemental gasses, and the hydrogen can be captured. The energy input is electricity. There are no additional greenhouse gas emissions.
An even more common way is to begin with methane (which consists of four hydrogen atoms and one carbon atom). Methane can be heated by steam (often in the presence of a catalyst) to produce hydrogen and carbon monoxide, and eventually carbon dioxide. This so-called steam methane reforming is the way most industrial hydrogen is produced.
From the manufacturer’s viewpoint, one advantage to this kind of industrial hydrogen is that you can use natural gas (which is cheap, abundant and mostly methane) as a feedstock.
Industrial hydrogen shell game?
In practice, industrial hydrogen is a bit more complicated than that: You can use other hydrocarbons besides methane as a feedstock and natural gas is not 100% methane.
Also, there are other byproducts. One turns out to be carbon dioxide, a major greenhouse gas. So if you care about climate, you would have to capture and sequester this carbon dioxide so it is not released into the atmosphere.
Watch the pea: If you are an oil and gas company, and have more cheap natural gas than you know what to do with, this whole steam reformation approach starts to look pretty attractive.
It should come as no surprise, then, that a number of major oil and gas companies are starting and investing in hydrogen ventures. Nor should we be surprised that oil companies are promoting hydrogen (subscription required) in a significant PR campaign.
A review of the rainbow
Back to colors. Yes, there are a lot of them. A dizzying array. The question is whether they are meaningful, and whether they clarify and illuminate hydrogen — or help confuse things further.
Let’s do a quick rundown, without claiming absolute authority.
- Green hydrogen: Made with clean, renewable electricity, ideally with electrolysis, and does not involve greenhouse gas emissions. Results may vary as to greenness, depending on production method. Today, less than 1% of hydrogen is produced this way.
- Blue hydrogen: Usually made from the methane in natural gas via the steam reforming method. Energy source may vary, but is likely methane. Often, this term refers to hydrogen produced with capture and sequestration of carbon dioxide byproducts. The capture part doesn’t always work.
- Turquoise hydrogen: Made starting with methane in a process that uses “thermal plasma electrolysis,” so that it is allegedly cleaner and less expensive.
- Pink hydrogen: Made with nuclear power as the source of energy, and may refer to electrolysis or steam reforming. Saudi Arabia, which has no shortage of hydrocarbons, has embraced it. Sometimes called purple or red hydrogen.
- Gray hydrogen: Made by steam reforming of natural gas methane without capture of carbon dioxide byproducts. This today constitutes the vast majority (well over 50%) of industrially produced hydrogen, which is in turn used as a feedstock for fertilizer and chemicals.
- Brown hydrogen: Made via the gasification of brown coal, not a clean process. Nations with lots of brown coal nonetheless think it is a great idea.
- Black hydrogen: Made by the gasification of black coal, and not clean.
Here are a few important facts to keep front of mind. First of all, by most accounts the amount of clean, green, climate-friendly hydrogen being produced right now is probably well under 1% of the total.
Meanwhile, the amount of hydrogen produced by steam reforming of hydrocarbons like methane is … most of it — 95%, says the Energy Department. You could quibble about what fraction of that currently involves carbon capture and what fraction is really fed by other hydrocarbons (e.g., coal gasification).
But another key fact to understand is that U.S. industry is already making huge amounts of hydrogen. The Energy Department estimates that about 10 million tons of it is produced in the United States alone each year. Worldwide production is about 70 million tons.
So where is all that hydrogen going? A lot of it goes to making fertilizer (the chemical formula for ammonia is NH3). Most of the rest is used in oil refineries, for example to lower the sulfur content of diesel fuel.
It’s important to know, then, what percent of manufactured hydrogen is truly “blue.” Sadly, reliable answers are hard to find. The standards for blueness are a little fuzzy — partly because carbon capture is less than 100%, and fugitive emissions of methane and carbon dioxide from other stages of the process are significant.
A recent report on a Shell “blue” hydrogen plant in Canada found that it was emitting more greenhouse gasses than it was capturing.
One other important truth. The boom-and-bust oil and gas industry is always scuffling to achieve profitability. This is less apparent today as the price of both oil and gas is heading upward. As Congress stumbles toward possible climate legislation, oil and gas lobbyists are not idle. Hydrogen funds have already been paid. The infrastructure bill President Joe Biden signed Nov. 15 includes some $9.5 billion to subsidize the hydrogen industry. And it stands to make even more convincing investors that hydrogen is the future.
Environmental journalists may find it hard to locate objective or disinterested sources of information on hydrogen. It’s still wise to know the bias of your sources and to go beyond the company whose project you are covering.
- Energy Information Administration: A federal agency whose main mission is to collect and publish accurate statistics on the U.S. energy economy.
- National Renewable Energy Laboratory: A federal agency whose mission is research on renewable energy.
- International Energy Agency: An international energy think tank that provides global data and analysis on many topics, including hydrogen.
- Earthjustice: An environmental advocacy group that has engaged on hydrogen issues.
- Hydrogen Council: A trade/lobbying group for the hydrogen industry, which includes the natural gas industry.
Joseph A. Davis is a freelance writer/editor in Washington, D.C. who has been writing about the environment since 1976. He writes SEJournal Online's TipSheet, Reporter's Toolbox and Issue Backgrounder, and curates SEJ's weekday news headlines service EJToday and @EJTodayNews. Davis also directs SEJ's Freedom of Information Project and writes the WatchDog opinion column.
* From the weekly news magazine SEJournal Online, Vol. 7, No. 5. Content from each new issue of SEJournal Online is available to the public via the SEJournal Online main page. Subscribe to the e-newsletter here. And see past issues of the SEJournal archived here.