The two fundamental problems that renewables face are that they take up too much space and produce too little energy. Consider Solar Impulse, the solar-powered airplane now flying around the world. Despite its huge wingspan (similar to a 747), slow speed and frequent stops, the only cargo that it can carry is the pilots themselves. That is a good metaphor for the limitations of renewables.
To run the U.S. economy entirely on wind would require a wind farm the size of Texas, California and New Mexico combined—backed up by gas on windless days. To power it on wood would require a forest covering two-thirds of the U.S., heavily and continually harvested.
more than a billion people on the planet have yet to get access to electricity and to experience the leap in living standards that abundant energy brings. This is not just an inconvenience for them: Indoor air pollution from wood fires kills four million people a year. The next time that somebody at a rally against fossil fuels lectures you about her concern for the fate of her grandchildren, show her a picture of an African child dying today from inhaling the dense muck of a smoky fire