Apple is almost ready to start powering its Maiden, North Carolina data center from its solar farm. When complete, phase one of the solar farm will be able to provide 20 MW of power. The initial solar installation will encompass nearly 100 acres; a second solar farm will be able to produce an additional 20 MW of power.
The solar panels are supplied by SunPower, a manufacturer of high-efficiency panels which use solar tracking mounts to ensure optimal exposure of the panels to the sun throughout the day.
The data center at Maiden will use a fuel cell system to enhance energy production when needed.
WCNC-TV recently did a flyover of the Maiden data center; you can see the installation in a series of photos available from Gigaom.
You can read more about Apple's use of renewable energy at:
Apple's Maiden Data Center to be Run 100% From Renewable Energy
Apple Provides Information on Its Planned Prineville, Oregon Data Center