The debate started by Stanley Pons and Martin Fleischmann isn't over yet. Credit: © SPL

Claims of cold fusion are intriguing, but not convincing. That is the conclusion of an 18-member scientific panel tasked with reviewing research in the area.

The findings, which were released on 1 December by the US Department of Energy, rekindle a 15-year-old debate over whether nuclear fusion can occur at room temperature.

According to the report, the panel was "split approximately evenly" on the question of whether cold experiments were actually producing power in the form of heat. But members agreed that there is not enough evidence to prove that cold fusion has occurred, and they complained that much of the published work was poorly documented.

Most scientists think that cold fusion is laughable, but when the dust settled, the researchers reviewing our work were evenly split. David Nagel , cold fusion researcher at George Washington University in Washington DC

The review is a positive step for the field of cold fusion, according to David Nagel at George Washington University in Washington DC, who co-authored the summary of cold-fusion work that the panel reviewed. "Most scientists think that cold fusion is laughable, but when the dust settled, the researchers reviewing our work were evenly split," he says.

Others remain sceptical, however. "It is astonishing that the panel didn't find cold fusion convincing after almost 15 years of additional research," says Bob Park, a professor of physics at the University of Maryland, College Park, and author of Voodoo Science, a book about junk science. Park says that although the quality of research has improved, no one should buy into cold fusion just yet.

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Fusion commonly occurs in stars like the Sun, where hydrogen atoms meld together to form helium and release huge amounts of energy in the process. Scientists have long believed that fusion has the potential to be an enormous source of power here on Earth. However, no one has yet been able to control fusion reactions because they only occur at temperatures and pressures similar to those found in stars.

It is astonishing that the panel didn't find cold fusion convincing after almost fifteen years of additional research. Bob Park , Professor of physics at the University of Maryland, Baltimore

Or so scientists thought until 1989, when Stanley Pons and Martin Fleischmann of the University of Utah claimed to have created a new kind of fusion inside a small canister of water. Pons and Fleischmann claimed that when they ran an electrical current between two palladium plates separated by water containing deuterium, a heavy isotope of hydrogen, it created a small but measurable fusion reaction.

In a highly publicized press conference in Utah, the scientists claimed that this 'cold fusion' had the potential to revolutionize the world's energy production.

Pons and Fleischmann's claims were quickly debunked by other scientists, who pointed out numerous experimental errors in the measurements. But the idea of cold fusion lives on in movies and science fiction, and among a small cadre of researchers.

Those researchers finally caught the ear of the US energy secretary, Spencer Abraham, who commissioned the review in August 2003 from the department's science directorate.

Although the reviewers remained sceptical, they were nearly unanimous in their opinion that the energy department should fund well-thought-out proposals for cold fusion. Nagel says that he expects many in the long neglected field to submit research plans in the coming months. "I will be among them," he adds.