In all of the various "green" energy schemes, there's one alternative fuel source, most notably for cars and trucks, that occupies something of a middle ground. Like the green energy proponents and climate scolds claim to want, it's clean, producing only water vapor as a waste product. It produces higher energy density than the generation sources of wind and solar, although not quite as much as oil, natural gas, or coal, and nowhere near the energy density of nuclear power.
And, like solar and wind power, it's good in some niche applications, but will never be able to replace gasoline and diesel as a primary transportation fuel for cars and trucks both private and commercial, except, again, in some niche applications.
That energy source would be hydrogen, which, like most alternative energy sources, has issues of its own. James Varney, writing at Real Clear Investigations, has presented some of those problems.
Although cheap, abundant hydrogen energy remains an aspiration rather than a reality, experts say debates around it highlight significant issues regarding American energy and national security, including the U.S. competitive position with other big economies – especially China. The contrasting goals of the Biden and Trump administrations highlight the uncertainty states and businesses face as the federal government capriciously offers or withholds support, and raise questions about whether the government should spend billions to create a market the private sector has largely ignored.
Supporters see it as something more than another tool in the anti-global warming chest. “The need for this industry is sound, there is a sense of global competitiveness and a need for action,” said Frank Wolak, the executive director of the Fuel Cell and Hydrogen Energy Association. “As far as the U.S., we need to ask how are we going to use our resources to respond to this global activity?”
The practical answer to that is "no."
The primary problem with hydrogen as a fuel is based on physics; specifically, that it takes more energy to produce hydrogen than can be recovered from the hydrogen itself. There has been some discussion of "green" hydrogen, but those schemes have troubles as well.
Water electrolysis using renewable electricity is one way to produce green hydrogen. The central piece to link renewable electricity to various decarbonization applications of hydrogen is a water electrolyzer, which uses electricity to split water into hydrogen and oxygen. With the growing availability of low-cost carbon-free electricity as a feedstock for electrolyzers, a positive feedback loop should be created: green hydrogen needs cheap renewables, and more renewables can be managed on the electrical grid by making green hydrogen.
That "positive feedback loop", then, depends on intermittent, unreliable, and low-density sources of energy to produce a motor fuel that is still lower-density than traditional fuels, while retaining all of the problems and inefficiencies of "green" energy sources. Hydrogen, to power a car or truck, uses a fuel cell, which isn't a terribly complex gizmo and is reasonably safe, a claim that you can't always make about the lithium-ion batteries used in electric vehicles; refueling a hydrogen vehicle, unlike charging an electric vehicle, is a task measured in minutes, not hours.
Some states, most notably California, have been trying for some time now to kick-start hydrogen as a motor fuel, along with trying to bring in the massive infrastructure required to support these vehicles on any scale. From a report in 2020:
Dozens of hydrogen buses are lumbering down city streets, while more and larger fueling stations are appearing from San Diego to San Francisco, financed by the state and federal governments. With the costs of producing and shipping hydrogen coming down, California is setting ambitious goals to phase out vehicles that run on fossil fuels in favor of batteries and hydrogen. Large auto and energy companies like Toyota Motor and Royal Dutch Shell have committed to supplying more cars and fueling stations.
There have been some increases in the number of these buses since, but only because of government subsidies.
Here's the onion: Any adoption of hydrogen as a motor fuel would take massive infrastructure construction. Gasoline has been in use since the early years of the 20th century; that refining, transportation, and sale infrastructure has been developing, changing, and growing for over a century, and no corresponding infrastructure for hydrogen as a fuel will be implemented overnight, or even over the next couple of decades.
And that's where it stands. Hydrogen as a fuel has the problem of physics, in that with current methods it takes more energy to produce the fuel than one gets out of it; it has the problem of economics, in that it is, as yet, impractical without subsidies, and any product that is impractical without subsidy is economically unviable. And, last but not least, hydrogen as a motor fuel will require not only solving the production problems, but also building an entire new infrastructure around and alongside the existing systems for producing diesel fuel and gasoline, which are already in place and already working very well.
In niche applications, as is the case with electric cars, hydrogen-powered cars and buses may be practical, to a point. But right now and for the foreseeable future, they are a novelty, not a practical policy, and while they occupy something of a middle ground between traditional motor fuels and the fever dreams of electric-vehicle proponents, this is a technology that is not yet ready for prime time.
