WASHINGTON -- After years of watching the world's fastest growing energy business from the sidelines, big oil companies are playing catch-up and investing billions developing new wind power projects.

"Shell and BP see wind as an increasingly important part of the energy industry," said Randall Swisher, of the American Wind Energy Association. "They want to look for new opportunities, and wind is clearly in their sights."

Shell is developing a $4 billion wind power project in the Texas panhandle. When complete it will surpass Florida Power & Light's "Horse Hollow" wind energy facility to become the biggest in the world.

Not to be outdone, legendary oilman T. Boone Pickens announced his own wind project in the same Texas panhandle area -- a project even larger than Shell's and costing $10 billion.

So far in 2008, investors in renewable energy stocks have been sipping champagne while the rest of the market has been in the doldrums.

Wind energy developer Nacel Energy has seen its stock jump 70 percent since IPO. The Wyoming-based Company announced an 80-megawatt wind power expansion January 10th -- enough energy to supply 25,000 homes. Analysts have a $3.07 target on Nacel -- nearly double its $1.84 close yesterday -- stating the Company is undervalued compared to its peers.