I’m not saying I’m going to crack some crazy software problem like general AI or something, but theoretically I’d love to be working on something that pushes renewable energy forward.

In what capacity I don’t know. I’m pretty convinced we are overlooking geothermal energy in the USA at least. I often wonder if we could both relieve potentially dangerous pressure bellowing Yellowstone while simultaneously harnessing its geothermal energy for example

But alas, I think the reality is I lack the expertise to even talk about this with any authority

Not saying you should but it is possible to gain a pretty respectable level of knowledge in almost any area within just a couple of years. Take online classes or even complete a fully online MS program. There are many examples of engineers and entrepreneurs who started in CS and then transitioned to more personally meaningful areas. (that’s my plan anyway!)