Wikiversity/Cold fusion/Nickel-hydrogen system
While possible heat-producing reactions with hydrogen using a nickel catalyst (or reactant) have long been reported, nickel-hydrogen became a major topic of interest with an announcement in early 2011 by Andrea Rossi. See Wikipedia:Energy Catalyzer and our subpage, Energy Catalyzer.
Other companies and organizations investigating the nickel-hydrogen system are Defkalion Green Technologies, Brillouin Energy (which has devices under test at w:SRI International). Francesco Piantelli had earlier reported anomalous heat in this system, and his work is under replication attempt by the Martin Fleischmann Memorial Project.
Rossi claimed that copper was being produced through transmutation in his device. If the reaction is the fusion of nickel and hydrogen to produce copper, it has often been pointed out, this is far more unlikely than the deuterium fusion that was originally thought to be the reaction involved in the Fleischmann-Pons Heat Effect.
However, there is no confirmed evidence as to the ash from nickel-hydrogen reactions, nothing comparable to the helium reported and confirmed for the FPHE. Storms predicts, from his general theory, that the ash is deuterium, and this has not been ruled out.
Defkalion Green Technologies is building an in-line mass spectrometer that should be capable of resolving the issue of ash.
As with all cold fusion or LENR systems to date, and as to what has been confirmed, there could be severe problems, not necessarily with the reality of the effects, but with reliability. Rossi's most recent public demonstrations show the problem: with three devices that were tested, one melted down, and the other two showed very different heat results. Defkalion's Hyperion reactor, tested in a live video presentation in 2013, may have generated much more heat than expected. Skeptics who doubt the reality of the effect don't notice this problem, which, until it is resolved, will certainly delay the appearance of any commercial product.
LENR, in general, appears to require very specific conditions in the material. In the original palladium deuteride work, cathodes made from the same batch of palladium would work only a fraction of the time, and even the very same cathode would fail to show the effect, show the effect, and then fail to show it again. The general cause of this is not controversial within the field: the material, under the influence of the loading and deloading of deuterium, changes surface morphology, and it appears that some precise surface structure is necessary to catalyze the effect. This may or may not include chemistry; electrolytic approaches are famously messy, the surface attracts every cation in the call, and it is, so far, impossible to precisely control this.
Gas-loaded systems can be simpler, but, still, the nickel nanopowder or alloy nanopowder that is used may sinter and become non-reactive, in a fairly short time. A fair amount is known about the DGT approach; and their stimulation method (a high voltage arc that bathes the material in a plasma) may keep breaking up the material, and provide increased control.
No data on the longevity of DGT devices has been provided, and reliability (i.e, how well they can know that a device, made through their standard process, will perform at first) can only be inferred. It's speculative.
Update on Defkalion Green Technlogies
In May, 2014, a report by Luca Gamberale, who had worked for DGT's European licensee, claimed that the excess heat shown in the 2013 demonstration was caused by a flowmeter artifact. The flow was reduced to a level low enough that boiling in the reactor caused backflow, and the flow meter could not distinguish forward flow from reverse, and thus indicated high flow when flow was very low, thus the heat measurement was drastically overstated. Because the condition that created the artifact was not easily set up by accident, and because DGT employees had deliberately prevented Gamberale from setting up flow confirmation, he clearly suspected deliberate fraud. Signs of the problem appeared shortly after the public demonstration.
So, the demonstration was in July, 2013, and the Gamberale report appeared in May, 2014. Over nine months, we didn't know. Gamberale decided that the public interest required that he violate a non-disclosure agreement. I (Abd) know scientists who signed such agreements. I was offered data if I signed one. I was willing, but the embargo was way too long, like five years as I recall. I didn't sign. Many other scientists did not trust Defkalion at all.
After the Gamberale report, Defkalion almost immediately disappeared, with a statement that they were, from now on, working privately until ready to announce a product. The Chief Technical Officer John Hadjichristos, has announced he is no longer working for them (as of October, 2014). So they now have no known technical personnel.
Did DGT ever have real results? They certainly convinced a lot of people, including scientists, that they did. Yet they, like the other commercial efforts, always kept critical aspects of their work secret. There is no way to verify what they claim, and commercial enterprises are not scientists, and have no professional obligation to avoid what is called, in business, puffery. They can fake demonstrations with impunity, if investors are not deceived.
see w:Energy catalyzer. Andrea Rossi's devices have been tested twice by a group of "independent professors," it's claimed. See the subpage. The second report, of a test performed in 2014 in Lugano, Italy, has received wide comment.
In December, 2014, a Russian scientist reported an independent test of a device resembling the Lugano device, but using phase-change calorimetry instead the calculated approach of the Lugano test. See the subpage.
A wiki associated with  has a great deal of news and information about work with the nickel-hydrogen system, starting with the namesake e-cat of Andrea Rossi. This page will index other content brought here from that wiki.