Back in March 1989, at a press conference in Salt Lake City, scientists Stanley Pons of the University of Utah and Martin Fleischmann of Great Britain's University of Southampton made a startling announcement. The researchers had managed to fuse the atomic nuclei of a hydrogen isotope to create helium — the same sort of process that powers the sun — and they'd been able to do it at room temperature, without putting in more energy than the process produced, as this Wired retrospective from 2009 details.
The research raised hopes of a new source of abundant energy that would replace fossil fuels and conventional nuclear power, as a CBS News story from that time reported. But other researchers who tried to duplicate the experiments were unable to reproduce the results, or else concluded that they were caused by experimental errors, according to a 1989 New York Times article. "Most of the scientific community no longer considers cold fusion a real phenomenon," Peter N. Saeta, a professor of physics at Harvey Mudd College, wrote in Scientific American in 1999.
The Dream Dies Hard
Even so, scientists' interest in cold fusion has never completely gone away, and they've continued to do research on it. Though nobody has been able to prove conclusively that it can be accomplished, that work actually has yielded valuable knowledge in other ways.
Several years ago, for example, Google funded a multi-year investigation of cold fusion that included researchers from several universities and Lawrence Berkeley National Laboratory as well. The researchers ultimately published a 2019 Nature article in which they revealed that their efforts "have yet to yield any evidence of such an effect."
"Nuclear fusion is a potential energy source that could provide a vast amount of power without harmful byproducts," Jeremy Munday, one of the participants in the Google research, explains in an email. He's a professor of electrical and computer engineering at the University of California, Davis. "For fusion to occur, the nuclei of atoms, which are positively charged, need to get close enough to fuse (join) together. If this happens, energy is released. The difficulty is that the positively charged nuclei repel each other. If there are a lot of nuclei close together — high density — and they have a lot of kinetic energy (high temperature), this reaction can happen. In nature, the sun is powered by fusion, but the temperatures and densities necessary to sustain those reactions are very difficult on Earth. Cold fusion is the idea that fusion could occur at much lower temperatures, making it feasible as an energy source on Earth.
"It's really hard to rule a phenomenon out, which is one of the reasons these concepts have been floating around for so long," Munday adds. "We didn't find any evidence of cold fusion, but that doesn't mean that it doesn't exist."
To a layperson, it might seem as if investigating and re-investigating to find evidence of cold fusion would be a waste of time and resources. But scientists don't see it that way, because as they search, they gather other sorts of knowledge and pioneer technological innovations.
"The spinoffs are perhaps one of the biggest impacts that our research in this area has had," Munday says. "Through the Google collaboration, we have collectively published more than 20 papers in high impact journals such as Nature, Nature Materials, Nature Catalysis, various American Chemical Society journals, etc. and have been granted two patents to-date. In addition to papers directly about lower energy fusion processes, we've had papers about the interesting materials physics and optical properties of metal-hydrides as well as their uses in sensors and for catalysts."
The HERMES Project
In Europe, a multinational team of scientists recently embarked upon yet another cold fusion investigation, the HERMES project, which will employ more advanced scientific techniques and tools developed in recent years.
"The purpose is to try to look for an experiment that would reproducibly produce some anomalous effects," says Pekka Peljo, in an email. He's the project's coordinator, and an associate professor in the Department of Mechanical and Materials Engineering at the University of Turku in Finland. "We are revisiting some of the previous experiments. Also, we are going to study electrochemistry of palladium-hydrogen and palladium-deuterium systems in detail, utilizing well-controlled model systems such as palladium single crystals. So shortly, HERMES is a combination of fundamental studies on palladium-hydrogen system, repetition of some promising earlier experiments, and development of new approaches. For example, we are going to look at reactions at higher temperatures utilizing proton conductive solid oxides."
Even so, the researchers aren't necessarily expecting to find evidence of cold fusion.
"The majority of the scientific field think it was most likely experimental artifact, i.e., it is not real," Peljo explains. "Basically, when palladium metal is loaded with high amounts of deuterium, it seems that most of the time nothing unusual happens. But sometimes, for reasons not well understood, it seems that something strange can happen. Originally, Pons and Fleischmann observed excess heat, but there are reports of other anomalous effects, such as neutron radiation or helium production. But there are a lot of reproducibility issues. Most likely, these reactions are not actually fusion, but instead some other nuclear reactions taking place in the metal lattice."
The HERMES researchers won't try to recreate Pons' and Fleischmann's research, while Peljo says would be too time-consuming and difficult.
"Instead, we are focusing on nanosized materials, where the loading should be much faster, and stresses due to the volume change upon deuterium insertion should be much smaller," he explains. "One of our main focus is so-called co-electrodeposition experiments, where Pd-D is deposited electrochemically. This approach was developed by Dr. Stanislaw Szpak and Dr. Pamela Mosier-Boss in the U.S. Navy SPAWAR Systems Center in San Diego, California. The experiments are well-documented and their results have been published in multiple peer-reviewed scientific literature, so our first approach is to try to reproduce their results."
"This is a high-risk, high-reward project, i.e., there is a very high likelihood that we will not be able to observe anything anomalous," Peljo says. "On the other hand, if the project is successful, we will have a reproducible experiment to probe these reactions. According to modern physics, no such reactions should take place, so a new theory should be developed to explain these reactions. There is also the possibility of developing novel heat sources, as these reactions are claimed to be producing excess heat from electricity."
Information that the HERMES research gathers about the fundamental properties of palladium-hydrogen systems could also help with developing a better process for producing hydrogen for fuel cells to power automobiles, according to Peljo.