Volume 4: Issue 2: Does dc Distribution Make Sense

This issue of IEEE Electrification Magazine will give readers a compelling opportunity to look at where we are today in the de versus ac discussion. Many of the authors have chosen to bring us into the present by revisiting the past "war of the currents" between Edi�son and Tesla at the beginning of the 20th century to show that, after a hundred years of ac infrastructure, there is good reason to revisit distributed energy delivery using dc. These reasons run the gamut from the role of dc in enabling electrification of rural homes in India (where both the need and opportunity are great), to LVdc distribution in green buildings and dc-enabled smart homes, to a plausible evolution from managed dc systems like universal serial bus (USB) and power over Ethernet, to nanogrids that have enabled increased plug and play of native dc electronic loads. Although many concepts still seem futuristic, "Solar-dc Microgrid for Indian Homes" by Ashok Jhunjhunwala, Aditya Lolla, and Prabhjot Kaur demonstrates that local dc distribution of solar power is happening today, transforming and lifting individuals, manufacturers of families, and communities. This issue also illuminates architectures, the integration of systems using commercially available hardware, lessons learned from highly survivable shipboard medium-voltage dc systems that are self-healing, and, of course, new developments in dc protective devices. All of these activities and achievements are paving the way toward more widespread integration of dc microgrid concepts at all levels of electrical power delivery with its attendant benefits.