With the bankruptcy of solar power development company Solyndra (and questions about a huge government loan to the company) in the headlines, Rob Black takes a look at alternative energy as an investment.

There are three large solar energy companies that have gone bankrupt over the past year. Although advocates like to point to alternative energy efforts in China as examples of what can be done, Rob reminds us that they are 100% government funded, and don't have to worry about turning a profit.

When the world economy was doing well, investments in alternative energy might have made more sense, because even in the capitalist countries, they received lots of subsidies from the governments. Now, as the European debt crisis looms and our own economy is struggling, those subsidies are gone. Unfortunately, the bulk of alternative energy companies simply aren't able to maintain profitability without government help, according to Rob.

Until these companies become profitable, they're not investments - they're simply interesting stories.