DC Microgrids in Buildings

For most of electrified history, alternating current (AC) has been the dominant form of power distribution.

Recently, new technological and economic factors have made a compelling case for expanding DC power use in buildings. With the greater adoption of solid-state electronics, solar photovoltaic (PV) power sources, other renewable energy systems, and energy storage systems that supply DC power, there is increasing potential for DC-based generation, distribution, storage, and utilization equipment.

This has given rise to an interest in the concept of DC “microgrids”, which are systems comprised of DC loads and distributed energy resources that can operate independently upon loss of the normal AC supply. Apart from the resiliency benefits of DC microgrids, DC power distribution can provide efficiency gains, since multiple AC/DC conversions are avoided. The benefits of DC microgrids include increased resiliency, safety, performance, efficiency, stability, as well as plug-and-play capabilities. Further, DC infrastructure can play a major part of “smart grid” power distribution, along with decentralization and digitization.

This research study reviewed current trends in DC-based distribution technology, including standards development activities, and evaluated forty-three recent DC microgrids (including commercial, institutional, industrial, and nanogrid residential projects).