DC Microgrids and the Virtues of Local Electricity

I would like to draw attention to a recent article in the IEEE Spectrum regarding the increasing potential of DC Microgrids in the future electricity networks posted by Rajendra Singh & Krishna Shenai on Feb 6th, 2014 (link) The following paragraph summarizes the main message from this article:

“With the decreasing cost of electricity generated by photovoltaics and wind turbines, DC microgrids may be the most efficacious way to provide electrical energy to those who have none. Just as cellphone use in the developing world exploded without the prior installation of landlines, DC microgrids could leapfrog over the traditional system of centralized AC generation. The market for microgrids in the developing world could be huge, and the benefits they would bring to what are now grossly underserved regions are monumental.”

What is even more interesting is also the historical remarks on the insights of Thomas Edison, who might take his “revenge” a bit more than a century later. The authors write:

“It’s been more than a century since Thomas Edison lost the great technological battle he waged against George Westinghouse and Nikola Tesla, the now-famous “War of Currents.” The idea Edison hoped to defend was that the world should run off direct current (DC) electricity. But his position just couldn’t stand up to the pounding it took from the logic of Westinghouse and Tesla’s competing scheme, which was to produce and distribute alternating current (AC).

With an AC system, the fledgling electricity industry would easily be able to shift voltages from one level to another, allowing power to be carried long distances at high voltages, which would minimize transmission losses. When the electricity arrived at its destination, it could then be converted to the low voltages appropriate for use in homes and businesses. Lacking that ability, Edison’s DC system would have required the installation of an electric generator in every neighborhood so that the low-voltage current-carrying wires wouldn’t have to be more than a few blocks long.

Generations of electrical engineers have learned about Edison’s efforts to exaggerate the dangers of AC in an attempt to make people wary of it. But Edison had some great insights about electric power too. For example, he considered its sustainability long before this became a popular issue. “We are like tenant farmers chopping down the fence around our house for fuel, when we should be using Nature’s inexhaustible sources of energy—sun, wind, and tide,” he remarked in a 1931 conversation with Henry Ford and Harvey Firestone. “I hope we don’t have to wait until oil and coal run out before we tackle that.”“