"Join an oil company and rise to the executive so you can redirect all R&D toward renewables."
Are they recruiting? I hear they make good money but I thought that you had to have an MBA or a Chemical Engineering degree to even consider getting a job with them. I have a high school friend that went to Stanford and worked as an engineer with Chevron for thirty years, and retired in his early 50s quite wealthy. Now him and his wife drive around the country enjoying Chevron's products in a luxury land yacht, Of course he started on that track when he was a teenager.
I think the problem with a plan like yours is that once you make it to the executive suite at Chevron, or BP, or Shell, you are going to be exactly like the other executives there. How could you rise that far if you weren't? If you are an engineer or MBA, why not just create your own company that makes or sells renewable energy, or join a startup that does that? If you create a good product or a good business plan providing something people would prefer to fossil fuels you should succeed without being sneaky.