PENSACOLA, FL—Jupiter Group, which manufactures nacelles and other components for General Electric wind turbines, has opened a new, larger assembly plant here. The new facility doubles the company’s manufacturing capacity.

To boost the energy output of wind turbines, manufacturers are developing taller structures with longer blades. That’s because the wind at 100 meters blows more steadily and 4.5 percent faster than it does at 80 meters, with an energy gain of about 14 percent.