Palo Alto-based Facebook said Thursday that the firm is opening up its first data center. The firm, which previously leased space from hosting companies, said the move to open its first custom data center is a result of the firm reaching the point where it is more efficient for it to lease entire buildings on its own. The firm said it will be using energy efficiency techniques, such as evaporative cooling systems, airside economizers, and server heat re-use to minimize energy use at the new data center.