The Maiden, N.C. site is reportedly being beefed up with a solar farm, according to The Charlotte Observer, based on permits Apple has secured to reshape the slope of part of the vacant land it owns.
Clues that point toward this assumption include an erosion control permit, notes about retaining soil moved "around the site from washing into creeks and other areas," and multiple gravel roads for access to solar panels.
Naturally, Apple hasn't announced anything publicly, and it is unlikely that it will anytime soon -- if ever -- before Apple files an actual building permit.
Nevertheless, it wouldn't come as much of a surprise considering Apple's firm stance on sustainable energy at its plants as well as eco-friendly components in its products. Reports about how much the Maiden location will cost vary between $500 million and $1 billion, and power for cooling systems and their respective servers are certainly going to cost big bucks.
Thus, an investment in solar energy such as this could save Apple more money (not to mention boost its greener image as a great PR move) in the long run.