I like to learn. One of the best ways to learn is to have a smart person explain things to you. David MacKay is a clever bloke and he has written a superbly readable book called Sustainable Energy — without the hot air. I think that you should read this important book. It is easy to do so as it is available online as a free pdf. You can also buy a copy from Amazon (US, UK).
This is a serious topic but the book is fun to read. In a way it is very simple, it contains a lot of back of the envelope calculations about how much energy we all consume, where that energy comes from today, and how that energy could be produced in a sustainable manner. As the same units are used for all the measurements, which are also displayed as simple boxes, you start to get a feel for the quantities involved. The more technical calculations are pushed to appendices at the end of the book so that it is a fairly lightweight read. I have been printing a few chapters at a time and reading them on my commute.
Mackay doesn't talk (much) about climate change. He communicates a scientist's annoyance with ideas where the numbers do not add up. I think it is a strength of the book that he sticks (mostly) to this topic. Occasionally his neutrality slips and he cannot resist an amusing quip about SUVs or other evils.
The book is centered upon calculations for the UK, but I think people in other countries will still appreciate and enjoy it. If you want to get a flavour of Mackay's writing there is a good short piece in the Guardian.