If someone told you that you would get less energy out of the cold fusion cells than it took to construct them, they’d tell you to take a flying leap. And you got to count ALL the energy that it takes to construct them. Mining the metal. Refining it. Shipping it. Manufacturing the cells. Building the buildings. If you have a gain in one stage but too many losses in another stage, you do not have a viable energy production process! You only have a means of shuffling existing sourced energy around, while losing some of it. This is one of the great criticisms of gasoline ethanol, incidentally. When you count the energy expended to get it, you might as well just have used pure gasoline. It might or might not fight pollution but it won’t fight energy waste.