Solar, wind and biodiesel have reached the point where not only are they viable, but they can, indeed, supply all of our energy needs.
A 1991(keep that year in mind, since the wind tech has advanced amazingly since then) survey of the harvestable wind energy in the US found that there is enough harvestable wind energy in three states, N. Dakota, Kansas and Texas, to supply all of our electrical needs, including factoring in growth, through the year 2030. Three states, all of our needs, with 1991 tech. <
http://www.earth-policy.org/Updates/Update24.htm>
Biodiesel, using algae feedstock, can supply all of our fuel needs. This one is a particualr win-win situation, since the necessary algae can be grown in wastewater treatment plants, in ponds that use algae for their first step in treating wastewater. A professor at New Hampshire has calculated that it would only take 15,000 sq miles of algae to supply all of our fuel needs.<
http://www.unh.edu/p2/biodiesel/article_alge.html> While I know that this sounds like a lot, to put it in perspective, that is only one tenth the size of the Sonora desert. What can't be produced using wastewater treatment ponds can come from aquaculturists, thus providing a boon to our small farmers.
We don't need intermediate steps, we don't need coal gassification, we don't need clean coal technology. We already have the means at hand to produce all of our own energy needs, cleanly, safely, and renewably.
Anything else is simply bullshit blathering designed to keep the current energy barons in power, as they further destroy our planet.