Solar Industry Learns Lessons in Spanish Sun
nytimes.com
nytimes.com
If you need extra money to run your solar plant, that means you are consuming more resources than a comparable plant.
Which means you are not "green". And often means it actually can take more energy to make solar power than it returns.
The only reason to do this is to spur research into solar energy that might eventually reduce the resources required. But this isn't really the best way to do that.
> Subsidies on solar plants are based on the time value of money if they produced all their energy in the first day they would cost far less than coal.
If that were true, you would not need subsidies, investors would be happy to fund it.
Back in the 1950's, Freeman Dyson did a study on the cost of electricity. Electricity costs much more to use than to generate. If electricity were free there would be only about a 5 percent drop in the GNP.
http://www.wired.com/wired/archive/6.02/dyson_pr.html
As for not needing subsidies, there's a significant cost of capital beyond inflation, and there's also some risk due to its being a new technology. These dissuade investors.
However opportunity cost means loans cave cost. http://en.wikipedia.org/wiki/Opportunity_cost
If you took 1billion$ today and invested it in high ROI wind farms you would have more than 1billion$ inflation adjusted by the time they broke down assuming reasonable care. However, you would have more money if you did just about any other moderate risk investment.