I don’t want to be Mr negative, but I’ve watched an awful lot of Robert Murray Smith videos on YouTube, and although they’re entertaining, thought provoking and educational, I‘ve yet to see him demonstrate anything which is practically useful.
Why do I watch his videos? Because they are splendid entertainment! Just don’t be fooled into thinking what he’s putting out are ideas worth spending time and money on replicating. He’s a lot more about science fair style demos than fully engineered, viable products.
Back on topic, he’s recently put out a series on a roof ventilator to generator conversion. The useable power which such a thing would generate will be tiny!