There’s an interesting post from Lloyd Alter that went up earlier this year that’s worth a mention. Alter points out that DC current could have a revival, partially because of the energy efficiencies associated with AC current and the conversion steps required. Much of the interest in DC power is being driven by cleantech related issues. For example, solar panels put out direct current that must then be converted, resulting in energy loss. Additionally data centers are experimenting with direct current with a recent study from the Electric Power Research Institute showing that using direct current increases efficiency in the data center by 15.3 percent. Facebook is actually building its Prineville, Oregon data center around direct current and combining the solar and DC idea, IBM has a pilot data center project in Bangalore, India that pairs DC current from solar panels with servers that are built to accept DC. DC would reverse a century old system but there’s definitely some interest out there in reducing the inefficiencies of AC to DC conversion.