Well... whether he's responding to a market need versus creating a market need versus responding to a moral obligation is very hard to untangle. That's part of why nobody's found a better system than capitalism yet - the most self-serving actions are often also the most public serving. I will say from the perspective of someone who specialized in renewable energy all through undergrad, renewable energy is cheap but requires storage. Expensive storage is the reason wind and solar have trouble competing with coal and gas on a dollers per watt basis. Subsidizing the creation of a lot of batteries by bundling them with cars people would buy anyway is the kind of brilliant but dirty growth hacking only a Silicon Valley Techbro would have the audacity to try. I can't comment on his motives, but I don't have a better idea for how to accelerate renewable energy adoption than the path he's pursued. Affordable storage is the keystone that supports that entire structure, in 2009-2014 it was the big unanswered question among my professors.
As for enriching himself by helping... I don't think there's a perfect solution there. The Rockefeller-Gates system of making money in one industry and funding purely philanthropic ventures in another comes with its own moral hazards. For profit work in a field of public interest comes with different ones. Both are preferable to taking no interest in the public good IMHO. Personally, if I was a billionaire I'd try to fund ventures that are in the public interest and also have paying customers, it promotes a certain kind of honesty that would be important to me, but I think any oligarch that claims to be trying to help should be given the benefit of the doubt, societal incentives are just so much more aligned that way.