AC voltage or DC? That's been a settled question for more than a century - ever since Thomas Edison's direct current lost out to alternating current, the format championed by the Serbian scientist Nikola Tesla. But today, people are starting to revisit the question, with many utility companies considering the wisdom, and savings, of using DC power for long-distance transmission.
Back when the standard was set, AC could allow the power plants to meet the demands of a growing number of energy consumers by transmitting electricity more cheaply. But DC power is far more efficient at moving electricity across long distances. That could be a key to linking renewable energy generators -- like the wind farms in the Plains States - to distant population centers.
Ryan Wiser, Lawrence Berkely National Laboratory: "The key advantages of going to DC come when you're talking about these very significant long distance transmission lines that might be required to bring renewables, for example, wind from Wyoming all the way to Southern California."