New developments in high-voltage DC electronics could herald an epic shift in energy delivery

By Peter Fairley

Stuttgart is one of the last places you’d expect to find in a power pinch. This south German city’s massive automotive plants run 24-7 without a hiccup, efficiency measures have held industrial power consumption flat, and solar panels flash from atop its major buildings. But now all that is at risk. The country’s accelerated shift from nuclear power and fossil fuels to renewable resources, such as wind and solar, has exposed a huge gap in its transmission capacity. If they are to survive, Stuttgart’s factories—and power consumers across southern Germany—will need to import a lot more power from the north, and Germany’s grid is already at capacity.

To fill the gap, Germany is considering an aggressive plan that would push high-voltage direct current, or HVDC, from its conventional position on the periphery of AC grids to a central role. The primary reason is simple: For the first time, HVDC seems cheaper than patching up the AC grid. But Germany’s transmission planners also have another motivation: They want to provide as much performance and reliability as they can to an AC grid that’s already strained by excess wind power. For that, they’re considering implementing power electronics that are capable of doing something that’s never before been done on a commercial line: stop DC current in milliseconds flat.

Germany’s plan could mark the beginning of something much bigger: a “supergrid” of inter connected DC lines capable of transporting electricity on a continental scale, ferrying energy from North Sea turbines, dams in Scandinavia, or Mediterranean solar farms to wherever demand is greatest at that moment…

Published in the May issue of IEEE Spectrum. Read the story at Spectrum.com.