Other ETFs linked to alternative energy have fared poorly as well. The First Trust ISE Wind Energy Fund ( FAN) and the PowerShares WilderHill Clean Energy Fund ( PBW) have fallen approximately 20% and 46% over the course of 2011. There is a chance that Buffett's latest purchase will be enough to inject some life back into the battered solar energy industry. Investors, however, should be wary of diving in at this time. We have seen in recent months the impact soured market sentiment can have on the performance of inherently volatile alternative energy companies. Many of the factors that have weighed on firms like First Solar in 2011 remain in play. There is a good chance that, as we prepare to ring in the New Year, FSLR and ETFs like TAN could continue to behave in a turbulent manner Given his substantial wind and solar investments, it has become clear that Buffett has a favorable outlook for alternative energy industry. What is your forecast for this slice of the energy sector in the New Year? Feel free to leave a comment in the space below. Written by Don Dion in Williamstown, Mass.