Apple said it is building the largest end-user solar array and carrying out the largest non-utility fuel cell installation in the US for its data center in Maiden, North Carolina.

Apple’s plans to build the solar farm at the site first came to light in October 2011, after it received a permit from local officials to reshape a slope on its 171-acre property in Maiden. At the time there was no confirmation the solar farm would be used for its data center.

Now, in its Facilities Report 2012 Environmental Update, Apple said the solar array will surround its LEED Platinum data center, expected to be launched in May.

“When completed, this 100-acre, 20MW facility will supply 42 million kWh of clean, renewable energy annually,” Apple said in its report.

The 5MW biogas fuel cell installation will come online later this year. Sitting directly adjacent to the data center, it will provide more than 40m kW of 24x7 baseload renewable energy manually.

“Apple is committed to pursuing energy-efficient growth by increasing our renewable energy participation to match the growing needs of our data center—through our own projects as well as partnerships with utilities and renewable energy providers,” Apple said.

The company, which usually gains attention for its much smaller mobile devices, has been increasing its emphasis on consumer cloud services and in turn data centers in recent years.

It has also been focussing on its goal of achieving “net zero energy” at its operations, from retail to technology facility, around the world.

“For more than ten years, Apple has purchased renewable energy for our facilities around the globe. Our facilities located in Cork, Ireland; Munich, Germany; Austin, Texas; and Elk Grove, California are currently using 100%,” Apple said in its report.

Apple said the company is currently working on a tiered approach for energy efficiency. Renewable energy initiatives such as its solar farm are its second focus, following general efficiency drives. Its next step will be to form industry partnerships with utilities and renewable energy providers to purchase renewables off the grid where location does not allow Apple to set up its own facility.

The solar farm and biogas plant are not the only energy efficiency initiatives undertaken at Apple’s Maiden data center.

It also uses a chilled water storage system, free outside air cooling, power distribution at higher voltages to reduce power loss and high efficiency LED lighting with motion sensors inside.

Outside it has a white roof, perfect for reflecting solar activity and keeping the data center cool and the build itself used recycled material where possible (14% of the data center is constructed in this way).