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Direct-Current Networks Gain Ground

Efficiency tempts computer centers to go DC

3 min read
Direct-Current Networks Gain Ground


Photo: Delta Products Corp.
Sparkless Plugs
Nobody thinks twice about unplugging an AC device, but with DC there's a danger. With 60-Hz AC, the voltage zeros out 120 times per second, nipping potential arcs in the bud. But DC's continuous current doesn't have that inherent safety. So manufacturers are building it into the plug itself. Taiwan's Rong Feng Industrial Co., which expects safety certification early this year, adds a short data pin whose early disconnection signals the attached device to shut off. "By the time you unplug the actual power wires, there's no current going through them," says Dennis Symanski, a senior project manager at the Electric Power Research Institute.

Manufacturers and energy efficiency gurus are joining forces to battle the black bricks multiplying in offices and homes, each one providing a dribble of direct current for a distinct electronic or battery-driven device. Their chosen remedy, DC power distribution, promises simpler equipment and significant energy savings. After more than a dozen beta installations worldwide, DC wiring is going commercial as manufacturers start selling the first products challenging AC power's 120-year dominance of electrical distribution.

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This photograph shows a car with the words “We Drive Solar” on the door, connected to a charging station. A windmill can be seen in the background.

The Dutch city of Utrecht is embracing vehicle-to-grid technology, an example of which is shown here—an EV connected to a bidirectional charger. The historic Rijn en Zon windmill provides a fitting background for this scene.

We Drive Solar

Hundreds of charging stations for electric vehicles dot Utrecht’s urban landscape in the Netherlands like little electric mushrooms. Unlike those you may have grown accustomed to seeing, many of these stations don’t just charge electric cars—they can also send power from vehicle batteries to the local utility grid for use by homes and businesses.

Debates over the feasibility and value of such vehicle-to-grid technology go back decades. Those arguments are not yet settled. But big automakers like Volkswagen, Nissan, and Hyundai have moved to produce the kinds of cars that can use such bidirectional chargers—alongside similar vehicle-to-home technology, whereby your car can power your house, say, during a blackout, as promoted by Ford with its new F-150 Lightning. Given the rapid uptake of electric vehicles, many people are thinking hard about how to make the best use of all that rolling battery power.

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