At last someone talking in understandable figures: the book by David JC MacKay, 2009, ‘Without the Hot Air’, explaines sustainable anergy and the sources of the daily energy consumption in easy chunks.
If you want to discuss sustainability further, you can download the book for free at www.withouthotair.com, and you can also buy it as hardback or paperback, for £45 or £19.99, resp.
To give you an idea of the tone of his book, here is a quote from the 10-page pdf synopsis:
Turning phone chargers off is a feeble gesture, like bailing the Titanic with a teaspoon. The widespread inclusion of “switching off phone chargers” in lists of “10 things you can do” is a bad thing, because it distracts attention from more-effective actions that people could be taking.
David J.C. MacKay. Sustainable Energy – without the hot air.
UIT Cambridge, 2008. ISBN 978-0-9544529-3-3. Available free online