Alternative energy has been a hot button issue for the last 50 year's and investors have always found a way to play this heated market. In the last decade, there has been the launch of a number of ETFs that offer a specialized basket of products for alternative energy exposure, with 12 of these funds still in operation today. Below we outline two green energy ETFs that have been battling for investor attention since inception: Powershares WilderHill Clean Energy Portfolio (PBW, A) and Guggenheim Solar ETF  (TAN, C+).

Holding between $172 million and $107 million in total assets under management each, these funds are easily the largest green energy funds currently on the market. PBW holds a mix of companies that are focused on greener and generally renewable sources of energy, as well as technologies that facilitate cleaner energy. TAN, on the other hand, is aimed specifically at the solar power industry, investing in companies that produce equipment, fabricate solar panels, or provide a direct service to this market. Newer to the market, TAN started trading in spring 2008, while PBW was already three years into the market.

Both funds were hammered in the years following the financial crash, with record outflows in PBW while TAN saw its first few years since inception with negative returns. A number of funds closed during this three-year window, but it is a testament to these funds that they were able to remain in operation.