The Roman Philosopher Lucius Anneaus Seneca (4 BCE-65 CE) was perhaps the first to note the universal trend that growth is slow but ruin is rapid. I call this tendency the "Seneca Effect."
Showing posts with label fuel cells. Show all posts
Showing posts with label fuel cells. Show all posts

Friday, May 14, 2021

A Concise History of the concept of "Hydrogen Economy"

Reposted from "The Hydrogen Skeptics" blog. 

The concept of "hydrogen economy" has a distinct "1960s" feeling. It is the idea of maintaining the lifestyle of the post-war period, with suburban homes, green lawns around them, two cars in every garage, all that. The only difference would be that this world would be powered with clean hydrogen. It all started with the dream of cheap and abundant energy that nuclear plants were believed to be able to produce. The idea changed shape many times, but it always remained a dream, and probably will continue to remain a dream in the future.


by Ugo Bardi

Before discussing the history of the concept of "hydrogen economy" we should try to define it. As you should expect, there are several variations on the theme but, basically, it is not about a single technology but a combination of three. Hydrogen would be used for: 1) energy storage, 2) energy vectoring, and 3) fuel for vehicles. 

This "hydrogen triad" misses the fundamental point of how hydrogen should be created. Often, that's supposed to be done using electrolysis powered by renewable energy but, alternatively, from natural gas, a process that would be made "green" by carbon sequestration. There are other possibilities, but all have in common being multi-step processes with considerable efficiency losses. And the fact of never having been proven to be economically feasible on a large scale.

Indeed, the immediate problem with replacing fossil fuels is not vectoring or storage, surely not powering individual cars. It is the enormous investments needed to build up the primary production infrastructure that would be needed in terms of solar or wind plants (or nuclear), which don't seem to be materializing fast enough to generate a smooth transition. Surely, not growing fast enough to be compatible with a relatively inefficient infrastructure based on hydrogen. Nevertheless, the "hydrogen economy" seems to be rapidly becoming the center of the debate

Indeed, the Google Ngrams site shows two distinct peaks of interest for the concept, both grew rapidly and rapidly faded away. But it seems clear that a third cycle of interest is starting to appear, and that is confirmed by what we can read in the media.

So, why this focus on a technology that lacks the basic elements that would make it useful in the near term? As it is often the case, ideas do not arrive all of a sudden, out of the blue. If we want to understand what made hydrogen so popular nowadays, we need to examine how the idea developed over at least a couple of centuries of scientific developments.

That hydrogen could be used as fuel was known from the early 19th century. Already in 1804, the first internal combustion engine in history was powered by hydrogen. The first explicit mention of hydrogen as an energy storage medium goes back to John Haldane in 1923, where he even discussed the possibility of using "oxidation cells" that we call today "fuel cells," invented by William Grove in 1838.

But these ideas remained at the margins of the discussion for a long time: no one could find a practical use for a fuel, hydrogen, that was more expensive and more difficult to store and use than conventional fossil fuels. Things started to change with the development of nuclear energy in the 1950s, with its promise of a new era of abundance. But, in the beginning, hydrogen found no role in the nuclear dream. For instance, you wouldn't find any mention of hydrogen as an energy carrier in the "manifesto" of the atomic age: the 1957 TV documentary by Walt Disney, "Our Friend, the Atom.

In the book derived from the movie, there was an entire chapter dedicated to how nuclear energy was going to power homes, ships, submarines, and even planes. But nothing was said about the need for fuels for road transportation. The atomic car was just briefly mentioned as "not a possibility for the near future." The engineers of Ford thought otherwise when, in the same year (1957), they proposed the concept of a nuclear-powered car, the Ford Nucleon. But nobody really believed that such a car could ever be produced. At the beginning of the nuclear age, there was no concern about climate change, and no one foresaw the need or the possibility of entirely replacing fossil fuels from the world's energy infrastructure.

The idea of hydrogen as an element of the new nuclear infrastructure started gaining weight only in the 1960s, in parallel with the problems that the nuclear industry was experiencing. The assessments of the world's uranium ores showed that mineral uranium was not abundant enough to support a large expansion of nuclear energy as envisaged at that time. But the industry had a technological solution: "fast" reactors that could be used to "breed" fissile materials in the form of plutonium. The fast reactor technology could have increased the duration of the uranium reserves of several hundred years, perhaps thousands. 

Fast reactors turned out to be more expensive and complex than expected, but the problem was not technological, it was strategic. The "plutonium-based economy" would have generated a gigantic proliferation problem. It was clear to the Western leaders that diffusing this technology all over the world put them at risk of losing the monopoly of weapons of mass destruction that they shared with the Soviet Union. 

So, if fast breeders were to be built, they needed to be only a few and to be very large to allow tight military control. They also needed to be large to exploit economies of scale. But that led to another problem: how to carry the energy to consumers? Electrical lines have a distance limit of the order of a thousand km, and can hardly cross the sea. The kind of plants envisaged at that time would be spaced much more than that from each other. It was at this point that the idea of hydrogen as an energy carrier crept in. It could have been used to distribute nuclear energy at a long distance without the need to distribute the reactors themselves. 

It was a concept discussed perhaps for the first time in 1969 by the Italian physicist Cesare Marchetti, He was, (now he is in his 90s) a creative scientist who proposed that just 10 gigantic fast reactors of a few TW each would have been enough to power the whole world. The reactors could be built on remote oceanic islands, where the water needed for cooling would have been abundantly available. Then, the energy would have been transformed into liquid hydrogen at low temperature and carried everywhere in the world by hydrogen carrier ships. In the image from one of Marchetti's papers, you see how an existing coral atoll in the South Pacific Ocean, Canton Island, could be converted into a Terawatt power nuclear central.

To paraphrase the theme of Disney's "nuclear manifesto" of 1957, the hydrogen genius was now out of the bottle. In 1970, John Bockris, another creative scientist, coined the term "hydrogen-based economy." In the meantime, NASA had started using hydrogen-powered fuel cells for the Gemini manned spacecraft program. It was only at this point that the "hydrogen car" appeared, replacing in the public's imagination the obviously unfeasible nuclear-powered car. 
It was a daring scheme (to say the least), but not impossible from a purely technological viewpoint. But, as we all know, the dreams of a plutonium economy failed utterly. With the oil crisis of 1973, the nuclear industry seemed to have a golden opportunity. Instead, it collapsed. We can see in the Ngrams how the concept of "fast breeder" picked up interest and then faded, together with that of nuclear energy. The reasons for the downfall of the nuclear industry are complex and controversial but, surely, can't be reduced to accusing the "Greens" of ideological prejudices. Mainly, the decline can be attributed to two factors: one was the fear of nuclear proliferation by the US government, the other the opposition of the fossil fuel industry, unwilling to cede the control of the world's energy production to a competitor. Whatever the causes, in the 1980s the interest in a large expansion of the nuclear infrastructure rapidly declined, although the existing plants remained in operation.

And hydrogen? The downfall of nuclear energy could have carried with it also the plans for hydrogen as an energy carrier, but that didn't happen. The proponents repositioned the concept of "hydrogen economy" as a way to utilize renewable energy. 

One problem was that renewable energy, be it solar, wind, or whatever, is inherently a distributed technology, so why would it need hydrogen as a carrier? Yet, renewables had a problem that nuclear energy didn't have, that of intermittency. That required some kind of storage and hydrogen would have done the job, at least in theory. Add that at in the 1980s there were no good batteries that could have powered road vehicles, and that made the idea of a "hydrogen car" powered by fuel cells attractive. Then, you may understand that the idea of a hydrogen-based economy would maintain its grip on people's imagination. You can see in the figure (from Google Ngrams) how the concept of "hydrogen car picked up interest. 

It was a short-lived cycle of interest. It was soon realized that the technical problems involved were nightmarish and probably unsolvable. Fuel cells worked nicely in space, but, on Earth, the kind used in the Gemini spacecraft were rapidly poisoned by the carbon dioxide of the atmosphere. Other kinds of cells that could work on Earth were unreliable and, more than that, required platinum as a catalyst and that made them expensive. And not just that, there was not enough mineral platinum on Earth to make it possible to use these cells as a replacement for the combustion engines used in transportation. In the meantime, oil prices had gone down, the crises of the 1970s and 1980s seemed to be over, so, who needed hydrogen? Why spend money on it? The first cycle of interest in the hydrogen-based economy faded out in the mid-1980s. 

But the story was not over. Some researchers remained stubbornly committed to hydrogen and, in 1989, Geoffrey Ballard developed a new kind of fuel cell that used a conducting polymer as the electrolyte. It was a significant improvement, although not the breakthrough that it was said to be at the time. Then, in 1998, Colin Campbell and Jean Laherrere argued that the world's oil resources were being rapidly depleted and that production would soon start declining. It was a concept that, later on, Campbell dubbed "Peak Oil." In 2001, the attacks on the World Trade Center of New York showed that we lived in a fragile world where the supply of vital crude oil that kept civilization moving was far from guaranteed. Two years later, there would come the invasion of Iraq by the US, not the first and not the last of the "wars for oil." 

All these factors led to a return of interest in hydrogen energy, stimulated by the popular book by Jeremy Rifkin, "The Hydrogen Economy," published in 2002. The new cycle of interest peaked in 2006 (again, look at the Ngrams results, above), and then it faded. The problems that had brought the first cycle to its end were still there: cost, inefficiency, and unreliability (and not enough platinum for the fuel cells). Besides, a new generation of batteries was sounding the death knell for the idea of using hydrogen to power vehicles. Look at the compared cycles of hydrogen and of lithium batteries.

 Note the different widths of the peaks. It is typical: technologies that work (lithium) keep being mentioned in the scientific literature. Instead, technologies that are fads (hydrogen) show narrow peaks of interest, then they disappear. You can't just keep telling people that you'll bring them a technological marvel without ever delivering it. 

At this point, you would be tempted to say that hydrogen as an energy carrier and storage medium is a dead platypus. But no, the discussion on the hydrogen economy is restarting, research grants are being provided, plans are being made. 

Did something change that's generating this new cycle? Not really, the technologies are still the same. Surely there have been marginal improvements, but hydrogen remains an expensive and inefficient method to store energy. So, why this new round of interest in hydrogen?

The vagaries of memes are always open to interpretation, and, in this case, we can suppose that one of the elements that push hydrogen back to the global consciousness lies in its origins of supporting technology for a centralized economy, the one that would have resulted from the widespread use of fast breeder reactors. In this sense, hydrogen is in a different league from that of most renewable technologies that exist and operate over a distributed network. 

So, even if the nuclear industry is today a pale shadow of what it was in the 1960s, there remains the fossil fuel industry to champion the role of centralized energy supply. And, obviously, the fossil fuel producers, who produce hydrogen from fossil sources, are those who are going to benefit most by a return to hydrogen, no matter how short-lived it will be. 

There may be another, deeper, reason for the success of the hydrogen meme with the public. It is because most people, understandably, resist change even when they realize that change is necessary. So, replacing fossil fuels with electricity-producing renewables is something that will force most of us to radical changes in our lifestyle. Conversely, hydrogen promises change with no change: it would be just a question of switching from a dirty fuel to a clean one, and things would remain more or less the same. We would still fill up the tanks of our cars at a service station, we would still have electric power on demand, we would still take two weeks of vacation in Hawai'i once per year. 

Unfortunately, people change only when they are forced to and that's what's probably going to happen. But, for a while, we can still dream of a hydrogen-based society that seems to be curiously similar to that of the US suburbs of the 1960s. Dreams rarely come true, though.