Andrea Rossi is firing up his 1 MW reactor today/tonight. That is, if it isn't a load of hooey, which many suspect it is.
Frankly, I don't understand most of the physics behind it, as many people claim it's cold fusion all over again (cold fusion 2: electric boogaloo?), but Rossi has said it's Low Energy Nuclear Reaction. Which, oddly enough, is another term for cold fusion.
When people refer to cold fusion, it's basically the latest in a long series of scientific 'breakthroughs' that turned out to be bupkiss. So, in a day or so, we'll find out if this is another "but it worked in our lab" boondoggle, or if it's a "holy shit, we changed physics (a bit)" moment.