The single biggest hurdle to the acceptance of LENR fka Cold Fusion is control of the reaction. There is little doubt in the learned scientific community that the anomalous and excess heat generated by the unidentified reaction is real. This has been proven thousands of times in the past two decades.
Much to the dismay of the pioneering Stanley Pons and Martin Fleischmann (whom took this to his grave), the lack of control destroyed their careers and gave Cold Fusion a permanent black eye. Early experiments show that excess heat is somehow released by the absorption of deuterium in a palladium lattice, but their crude experiments were not controllable and virtually impossible to reproduce by others. Their work was dismayed as pseudoscience and all but killed further funding for research.
Twenty plus years later, the entrepreneurs now seem to have the upper hand. While the research dollars disappeared, experiments continued quietly in small labs across the globe. There are a handful of companies actively working to bring a LENR device to market. Again, control is the key issue if one believes Rossi, Brillouin, Blacklight and Defkalion all have devices which produce excess heat.
Brillouin Energy Corporation seems especially in tune with the issue. Its founder, Robert Godes, has been working for many years to solve the control issue. His innovations apparently allows Brillouin a controlled and predictable output and a working theory they call a Controlled Electron Capture Reaction. Their theory and stability has generated millions of dollars in funding and a relationship with the Standford Research Institute.
Further developments in control will spur more funding and more research. As the phenomenon is more fully understood, a solid reproducible reaction will be available to everyone.