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Message: <blockquote data-quote="Virate" data-source="post: 1553368" data-attributes="member: 19603">Each year we race little solar powered cars across the nation.  Each year it is a joke compared to the gasoline cars that pass them like they are standing still.Please excuse my skepticism, but if solar powered cars are any indication of the potential of solar power, then that industry is in real trouble.I don't buy into the bit where Solar will power the world, we would have to convert a significant potion of the earth's surface to this task.  Destroying natural environments and reducing agricultural land.  To make the US completely sustainable by solar power would require us to convert 40% of our land mass into solar collectors.  This is a terrible prospect, and ultimately too expensive to build or maintain.As for coal, it only supplies 25% of our energy in the US.It isn't nearly as easy to transport, nor is it as dense.Coalmining operations actually run on oil, not coal.Coal used to have an EPR of 100 to 1, meaning 100 units of coal extracted for the expenditure of 1 unit of coal.  It is now at 8 to 1 and by 2020 it will be only at 2 per 1, making it a very inefficient source of power.As far as Ethanol, there are some estimates that actually conclude that it actually takes MORE energy to make ethanal than it produces, even the best estimates put Ethanal at an EPR of 1.7, making it extraordinarly inefficient.Sorry to be a killjoy.</blockquote>