We’ve had small scale fusion for years, do a search for “Farnsworth Fusor”. The problem has been the getting more energy out than in.

Even Pons and Fleischman thought they had only 200 fusions an hour. Even if it had been repeatable, it seems unlikely that anything based on their apparatus would produce industrial quantities of power.

The problem with commercial applications ( and wind and solar for that matter ) is that modern industrial society needs a lot of power. I’m not talking stereo’s, computers and TV’s … I’m talking boilers and pumps for heat water and sewage, motors for aircompresors, elevators, automatic doors, furnaces, milling equipment … all of these things use a lot of power, need it reliably ( not just sunny / windy days), and can’t be got rid of easily or quickly. We have a very energy wasteful infrastructure, and we can’t change it over night. And there a lot of losses getting the power from point A to point B as well.

In short all the problems that have kept fuel cells as, at best, a niche product for 40 years would be working against any type of cold fusion home power plant, only more so.

Doesn’t mean it isn’t worth pursuing, but even if they have a breakthrough, I would be stunned if really made much difference to the way we lived our lives in less than 50 years. Human civilization has a lot of inertia built in to it.