Love this very simple explaination of energy source comparisons.  Pretty simple really.

Allencic says:

Alternative energy only makes sense if you truly believe that carbon dioxide is the devil incarnate. If it’s not, there is no point whatsover for wind or solar.
It all comes down to E=MC2 or for non-nuclear, E=MV2. To get enough “E” you either need lots of “M” (mass”) or very high “V” (velocity). Wind has very little mass and thus must move very, very fast to produce much “E”. Or in practical terms you must litter vast areas of the landscape with windmills. Solar is fine with E=MC2 but the problem is the nuclear reaction is 92 million miles away and once again enormous areas of land must be covered with solar panels to produce enough “E”. The chemical reactions that release energy are far more efficient and of course, that’s why we’ve burned carbon based fuels for thousands of years.
Solar has about 1/10th the energy density of wood, wood is about half as energy dense as coal,coal about 1/2 that of gasoline and of course the really winner is nuclear power which is around 2 million times as energy powerful as gasoline.
Those who advocate wind or solar simply have the laws of physics against them. They can’t break those laws without destroying the landscape and/or the economy.

Taken from a thread from