Today there is no reasonable doubt that Cold Fusion is real.
There are many reproduced evidence, past or current. Some peer-reviewed.
Theoretical arguments are epistemologically void, since in real science, when theory and experiments disagree, experiments rules.
No serious argument could rule out all (if much) of successful LENR experiments.
Some experiment were badly made, positive or negative in the early time, but after few years, skeptic electrochemist like Heinz Gerischer had enough evidence to be convinced.
The replicated experiments proving tritium production were so impossible to deny by measurement artifacts that Huizenga invoked a conspiracy theory.
Same for the Elforsk test, and globally for most critics when looked in details.
Anyway one have to notice that LENr was declared pathological science at an APS conference less than 1 month after publication, and the 3 key negative experiments were done in 6 weeks, with one confirmed (excused) case of data tweaking, and few errors in calorimetry. Current state of knowledge on LENR anyway says that those experiments could not work, even with a good calorimetry (see ICCF18 miles calorimetry comparison,see Edmund storms student book).
Today the most replicated experiments are based on Palladium Deuterium, electrolysis and gas permeation. Production of heat have been proven above 50 sigma, and at COP above 2.
The only problem which stopped most research was that electrolysis limited temperature, thus potentiam usage.
Anyway NASA 89 replicated 2005Tsinghua/2007Biberian/2008NASA, based on gas permeation showed another method... this method, using nano-structured materials containing nickel and 1Hydrogen is the base of todays industrial developments by Leonardo Corporation, Defkalion, Brillouin, Lenuco, Nichenergy, Celani/Kresenn.
The reactor of Leonardo Corporation have been tested and confirmed as producing much more heat than any chemical process known on earth. 7 physicist from 4 universities and 2 countries, in absence of the inventor, with access to electric input and reactor walls. A black box test, with unrestricted access to the out of the boxes.
There is only one public critic, whose conspiracy theory structure, evident incompetent in thermography, and lack of serious reading of the report, make serious people consider as crackpot-like. As Bo Hoistad said on ibtimes, this is a shameful article. It is however sadly much quoted as a reason to doubt.
Elforsk is confident enough on the result to publish an article in their corporate magazine "Elforsk Perspektiv" in Nov2013.
The reactor of Brillouin, in early version have been tested by SRI, and a researched of SRI presented the results at ICCF17.
An employee of NASA (Nelson) , known to have criticized Rossi previously fro too secretive behaviors, have tested the reactor of Defkalion. the report have leaked, and inside he clearly report cooperation and goodwill of Defkalion during his tests. He was sent by a NGO, not NASA. Interrogated by a Forbes journalist, Gibbs, he confirmed.
Beside them, National instruments is proudly sponsoring ICCF18 and invited LENR actors at NIWeek2012, whit his boss supporting LENr "Edisonians" during his opening conference. Before that the "Big Science segment" boss of NI, who was selling control technology for tokamak, have made conference supporting LENR in BRussels and Rome parliaments early 2012.
Today 2 teams in ST Micro (ST NewsVenture from Grenoble, and Mastromatteo from Italy) are interested in LENR, and they own a patent.
Toyota (Technova) and Mitsubishi (MHI,Iwamura) never stopped researching, and Japanese journals (JJAP...) and Wikipedia don't block LENR claims.
Today SRI (Stanford Research Institute the one of SiRI), ENEA (Italian new energy state labs) and US Navy NRL work together and replicate each others. They work to identify key parameters and improve the electrolytic method. They have mostly identified all parameters, and finally seen the importance of impurities and crystallographic parameters in the palladium. They presented their collective results at ICCF18 and in a conference in Brussels
Today nearly all failed experiments published or not, are well understood. (Ask Edmund Storms for details).
Basically in the first month, some key condition were not fulfilled (loading, current density, impurities, polarity).
Epistemologically, asking for a new phenomenon to be fully reproducible when you don't master it is an unforgivable error. There is no excuse for any scientist to have used that argument, unlike you ignore the early time of any technology like semiconductors or planes.
Among pathological argument you also find the "tea kettle" argument which is scientifically absurd, pretending that something that is not useful is not real. Some ask of high COP, while what is important is the signal over noise ratio, which is better at low power.
some claim there is no replications, while there are many. Tritium experiments have been replicated among many countries and kind of organizations (texas AM, BARC, Amoco...).
Even more organization have proven LENR heat production.
He4 and Heat production is replicated by ENEA and Miles.
F&P have been replicated exactly by Longchampt (CEA) in 1997 with modern tools, but there are many less exact replication.
Some isothermal calorimetry have been done too(McKubre), ruling out CCS theories, like does Tritium and other transmutations evidences.
recently Toyota published in Peer-reviewed journal (JJAP) a replication of Mitsubishi LENR transmutation experiments.
One argument is often that results are not published in peer-reviewed journals. It is factually false, and beside many others you can find many articles by Pamela Mosier Boss of US Navy Spawar, Mitsubishi and Toyota.
It is however a fact that top journals like Nature and Science have shown an unethical bias against cold fusion, both refusing to retract or correct erroneous negative paper (caltech, MIT), or to allow LENR paper to be published despite positive-peer-review (Oriani) or simply dumping it for absurd reasons (ENEA Deninno report41, correlating He4&Heat).
Note that Edmund Storms is currently hired by naturwissenschaften to organize peer-review of LENR papers.
Beside not being arguments against experiments, theory cannot rule-out LENR despite what is erroneously said. There is enough complexity inside lattice to allow collective behaviour, screening, as we discover every year in material science and lattice physics.
Today the only reason to doubt on LENR reality is that the size and depth of collective denial is so huge that naive people refuse to accept it, and prefer to accept the popular smaller conspiracy theory.
in fact in history, collective delusion is very common and history have been rewritten to hide that fact, less in the past.
The work of Thomas Kuhn, Roland Benabou "Mutual assured Delusion", various Groupthink theories, and simply honest history of science give simple and unsurprising explanation on what happened.
Today, despite opposition, LENR is supported by industrialist who simply believed their instruments, and admitted their theoretical ignorance. It is clear from their profile that they have seen enough evidence to oppose to popular position against LENR.
So yes LENR is replicated. without doubt since 1991 as said Gerischer. By industrialists recently. And it is publicly ignored.
This is a usual situation. See Wright brothers story.