The ETF industry has been credited with bringing exotic asset classes and investment strategies within the reach of all levels of investors. But it has also provided a potentially better way to invest in asset classes and industries that have historically exhibited significant volatility.

Since the ETF structure provides immediate diversification of holdings at a reasonable rate, it has been embraced as an efficient way to invest in junk bonds, micro cap stocks, and tech companies. ETFs have become a popular way to establish both long and short positions in the alternative energy industry, and multiple funds now offer targeted exposure to solar energy.

When we look at the performance of green ETFs in 2009, most rose 30-40%, easily beating the S&P 500's gain of 28.8%, but underperforming the Nasdaq's gains 43.9% and a multitude of individual stocks.

Green stocks that outperformed in 2009 include:

Renewable energy and clean tech companies and exchange traded funds are getting the boost they need to put their plans into action, after President Barack Obama has allocated $2.4 billion toward the sector in yesterday’s budget.

Obama’s new clean energy budget dusts the old one, which had just $113 million allocated to renewable energy initiatives, reports Laura Isensee for Reuters. Although the money has increased, criticism remains.