The majority of our devices today use DC, so let’s give it to them. Using a DC distribution circuit for a building brings many benefits such as better compatibility with renewables and battery storage, greater safety and higher efficiency no matter what the type of power input.
By moving the point of conversion of AC to DC from the device to a little farther upstream closer to the source, we can capture conversion efficiencies that cost too much to provide for loads as small as your cell phone charger… If you have 15 power supplies turning AC into DC in your house, it’s quite likely the average efficiency of those devices is about 70 percent. If instead those devices were optimized around a common DC input like 24-volt DC, we could achieve 90 or 95 percent efficiency.
The article notes the efforts of the EMerge Alliance to develop standards for DC power distribution in commercial buildings.