... physicists Andrea Rossi and Sergio Focardi of Italy's University of Bologna have unveiled their supposed massive breakthrough. They don't just claim to have figured out how to make a cold fusion reactor, the actually say that they have built one and already tested it, with lots of new reactors ready to ship within the next few months.
Before you get out your checkbook, let's examine what's going on here. The scientists claim that a reactor has been running a factory for the last two years, but nobody knows what they're talking about and the physicists did not elaborate on where or what this factory is.
They also don't have any theoretical foundation for their work. They say the reactor takes in nickel and hydrogen, and then it produces copper and tons of energy, all at room temperature. But they admit they don't know how any of that is going on, and there's a ton of theoretical work that says reactions don't work in the way the pair have described. It's not impossible for an empirical discovery to precede the theoretical understanding, but in this case it's an excellent reason to be very skeptical, if not outright dismissive.
The scientific community definitely wants nothing to do with their work, as Rossi and Focardi have had to create their own journal, the Journal of Nuclear Physics, just to get their scientific paper published. The European Patent Office has also pretty much rejected it out of hand, as a preliminary report explains:
"As the invention seems, at least at first, to offend against the generally accepted laws of physics and established theories, the disclosure should be detailed enough to prove to a skilled person conversant with mainstream science and technology that the invention is indeed feasible. … In the present case, the invention does not provide experimental evidence (nor any firm theoretical basis) which would enable the skilled person to assess the viability of the invention. The description is essentially based on general statement and speculations which are not apt to provide a clear and exhaustive technical teaching." ...
via No, Italian scientists have not discovered cold fusion.