He has never conducted a successful enterprise.
I have heard he successfully developed Diesel engines that run on biofuel, and later sold that enterprise for a lot of money. I do not know the details.
As for the experiments or tests he conducted that Jed finds inconclusive, they are only inconclusive because Rossi failed to provide adequate data to evaluate them properly.
The tests I refer to were conducted by other people. In two cases Rossi never visited the test sites as far as I know. I also refer to the first Levi test. Levi claims that Rossi did not participate.