Alternative energy isn't cost effective, yet.

The only reason it exists is because it is funded by OPM - Other People's Money.

As long as it is politically correct, federal funds will keep flowing.  When the political winds change, so will the funding. 

The problem is that the U.S. Government and the State Governments are broke.  The 'Change' so many people voted for is not turning out to be what they expected.  As early as 2010 the political winds may shift.  Responsible leaders may attack the National debt with the vigor it requires.  That would end the Federal and State funding for alternative energy.

The power companies are now required to offer rebates for many alternative energies.  Those rebates are paid by the ratepayers.  As economic time continue to decline, ratepayers may question the authority of the power companies to 'tax' the ratepayers.  If the courts consider the surcharge a tax, they may disallow the charge to the ratepayers.  Without the money from the ratepayers, the power companies cannot afford to extend the rebates.

In the end, it is the tax payer/rate payer that is responsible for the viability of alternative fuels.  If their support waivers, the game is over.