Shares of clean energy firm FPL Group Inc., which reported second quarter earnings today, plunged 6.5 percent on Tuesday after the company said it now expects adjusted 2009 earnings at the lower half of its range of $4.20 to $4.40 a share on a continued weak economy and poor wind resource.

Shares of FPL were down $3.90 $56.14 in early Tuesday afternoon trading on the New York Stock Exchange.

FPL Group said that additional new wind assets helped the company increase its net income to $370 million or 91 cents per share compared to $290 million or 52 cents per share in the same period a year ago.

NextEra Energy Resources, a unit of FLP posted a higher net income of $183 million while the Florida Power & Light unit's net income dropped by $4 million, the company said today.

On an adjusted basis, FPL Group's earnings were 99 cents per share or $401 million compared with $375 million or 93 cents per share a year ago.

FPL's wind assets increased by roughly 1,370 megawatts compared to 2008 second quarter. Those assets accounted for adjusted earnings per share of 5 cents with an additional 4 cents attributable to the ability to take the value of federal tax credits in the form of cash grants on 685 megawatts of wind projects in 2009, the company said in a statement.