A little known but fast-moving trend of the last decade or so has been the drop in cost and rise in efficiency of photovoltaics -- that is, panels that convert solar power into electricity. This guy finds that under now-current technology, one could supply an average European family's energy usage with 30 lb. of silicon -- roughly $700. Not $700/year. $700 to produce the panels that will supply that family's energy by themselves forever. By comparison, it costs $6000 to produce enough energy from coal to supply such a family for 25 years.
Moreover, he forecasts the continuing price drop in photovoltaics out 7 years and finds it to be the cheapest energy option on the planet.
Obviously there are a lot of "if"'s in his picture. If photovoltaic production continues at its current speed, if the price drops at the same speed as now for the next decade, etc. Still, if it takes twice as long as he predicts, we're still only talking about 15 years.
What if it's true?