On the surface, green energy sounds like a great idea. Unfortunately, it is extremely costly and requires heavy government subsidies.Last year, the epic downfall of Solyndra — the former solar cell manufacturer backed by the Obama administration — was one of the most notorious blows to the industry.As with most young industries, experts argue that green energy just needs time before it can reach economies of scale and become cost effective.But lately, those time frames have become extended. Meanwhile, fossil fuels like coal and natural gas continue to be devastatingly cheap.We pulled together key charts from the studies that...