Facebook implemented the OCP's high-efficiency electrical system [PDF] in its Prineville, Ore., data center. It's a 48VDC UPS system integrated with a 277VAC server power supply. Among its features is a novel approach to electrical distribution from an on-site substation, which eliminates unnecessary losses from transformations and conversions. Typical energy loss during conversion runs at 21 to 27 percent, according to Facebook; at the Prineville data center the loss is 7.5 percent.
Other design elements include a diesel backup generators, battery monitoring, server-battery backup, and energy-efficient LED lighting systems. The system is designed to meet or exceed an array of standards, including those from the National Electrical Code, National Fire Protection Code, Institute of Electrical and Electronics Engineers, and Underwriters Laboratory.