David MacKay is such a role model.
He started off as a physicist, then later moved into study of computational and neural systems. He is widely known for his contributions in Machine Learning and Information Theory.
His book "Information Theory, Inference, and Learning Algorithms" from 2003 is not only awesome and informative, but available for FREE
as a PDF download on his website. (http://www.inference.phy.cam.ac.uk/mackay/itila/book.html
Since about 2005, he began to devote a lot of time to public teaching about energy. He published his findings in 2009 in a book called "Sustainable Energy - without the hot air". The book is also available FREE
as a PDF download. (http://www.withouthotair.com/
) and is on my immediate to-read list. It has been widely endorsed, for example Bill Gates called it "one of the best books on energy that has been written". 9 months after publishing the book, he was appointed as the Chief Scientific Advisor to the Department of Energy and Climate Change in UK.
He also delivered a TED talk on renewable energy earlier this year in March (2012): http://www.ted.com/talks/david_mackay_a_reality_check_on_renewables.html
It's always a relief to hear about some of the smartest people working on some of the hardest and most important issues that our civilization faces.
Awesome research, contributions, focus, and spreading of scientific information in consumable format to everyone for free => WIN.