Where does the field of study stand at present? First of all, a large number of studies (Storms 2007) reporting production of large amounts of power and energy are now available for evaluation. Some of the individual results far exceed the energy from any conceivable chemical or mechanical source. Second, nuclear products including helium, tritium, neutrons, and transmutation products have been reported by numerous laboratories using a variety of methods of production and detection. Helium and heat production are found to be correlated based on a significant number of studies. In addition, the measured values for the ratio between energy and helium production rates show good internal consistency and a close relationship to the value expected when two deuterons combine to produce helium. Third, radiation has been detected that can only be produced by nuclear processes. While some of the measurement could be influenced by error, contamination, or misinterpretation, the large and growing collection cannot be fully explained this way. Therefore, the claimed occurrence of unusual nuclear reactions under conditions thought not to cause such reactions is supported. The challenge now is to discover what mechanism or mechanisms can produce all of the different nuclear products and how the process can be made more reproducible so that it might be more easily studied and developed as a source of energy.
The absence of a useful theory is presently a major handicap to progress. Especially troubling is the tendency of some people to promote ideas that are in direct conflict with a basic understanding of how Nature is known to behave based on well established observation. The cold-fusion effect may be novel but it exists in the context of a large and well-developed understanding of nuclear interaction that needs to be included in any useful theory. The first stage in this process requires the nature of the required environment, the NAE, to be identified. At the very least, the almost universal assumption that palladium is uniquely involved needs to be reexamined. Indeed, when palladium is used, the active region is not palladium deuteride but a very inhomogeneous and complex alloy. The location of the NAE in this region is not known.
If a NAE can exist in living cells, the consequence is huge. This would allow environmental contamination to be reduced using bacteria and mean that the abundance of elements on earth has been modified by the presence of life. The conditions known to exist in living cells also might severely restrict the nature of the NAE in non-living matter, an insight that could help define the NAE. The challenge to the imagination is obvious.
What are the consequences of this phenomenon being real? The answer to this question involves science, energy policy, and politics. Clearly, if the rate of the energy producing reaction can be increased, controlled, and sustained for long periods, this energy source has the potential to replace all other sources. In many ways, cold-fusion produces the ideal energy because the easily extracted fuel (deuterium) exists in inexhaustible amounts in all water, the process of extraction and energy generation appear to create no harmful products, and the generator can be small enough to power individual dwellings. Ordinary hydrogen (protium) may even be a source of nuclear energy under certain conditions. General application can be expected to have important consequences, both good and bad. At the very least, this energy may offer a solution to the global warming problem. At the worst, economic distress will result as the present energy infrastructure is replaced. From a scientific point of view, the ability of “normal” materials, including living organisms, to apparently initiate nuclear reactions shows that present knowledge about nuclear interaction is painfully inadequate. Efforts to improve this understanding can be expected to reveal other amazing and useful phenomena. The stakes are enormous and attention needs to be paid to the possibilities, no matter how remote they may seem. In a rational world and in the face of growing ecological disaster from using carbon-based fuels, every possible energy source would be explored, no matter how unlikely. Why is cold fusion the only proposed source that is widely ignored at the present time?