The American Recovery and Investment Act had already boosted investment tax credits for solar panels from 10 to 30 percent. But the “private letter ruling” obtained by Solyndra from the IRS increased the tax credit for its products by an additional 30 percent.

That last 30 percent, however, only kicked in for solar panels installed on so-called “cool” roofs, painted white to reflect sunlight. And Solyndra was then the only vendor whose solar panels fit the bill.

Consumers who installed $10,000 worth of Solyndra solar panels on their roofs in 2010, then, were eligible to get $6,000 rebated from the government when they filed their income tax returns.