Well, you know, we're human beings. We breathe, we exhale, we do all sorts of things. There can be no such thing as a clean technology. There can, however, be a cleaner technology. I would argue that the criteria for progress should be creating fewer problems than those that exist in the real world. You need to look at all the impacts of those technologies, their costs, and whether they're really having an impact on carbon emissions.
So there can be cleaner technologies, but you need to look at the whole picture, not just at whether they're renewable but also whether they're creating fewer problems than those that existed before.