Some people think that solar is too expensive to justify public spending. Put your public funds into energy efficiency now, which is much cheaper, and wait for solar’s costs to come down. Severin Borenstein, Director of the University of California Energy Institute, is one such person.

Others think that the best way to have cheap solar in the future is to invest in building a market now — if there is a market, private money will flow into R&D, ecomonies of scale will develop, and costs will come down. JP Ross of Vote Solar is a member of this camp.

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On Saturday, they went mano-a-mano on Air America’s EcoTalk. Listen to the fireworks here.

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