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Electric power: Clean energy infrastructure driving switch from AC to DC

nikola tesla
Nikoa Tesla, pictured in his Colorado Springs lab in 1899. Picture courtesy of

Nikola Tesla was a famous scientist who developed alternating current, the means of distribution for electricity for the vast majority of devices, appliances and machines in households and factories and just about every other electrified thing in the world today. 

But even as Tesla was inventing much of the technology used in the alternating current electricity supply system, another famous inventor, Thomas Edison argued that direct current was the best way to distribute electricity.

By the time Tesla tech came onstream, DC had already been in use for a decade, but within a relatively small area, and Edison lost that argument mostly because the components of an alternating current grid enabled electricity to be carried far and wide beyond the power generating facility. 

solar farm
Solar power plant, in Las Vegas, US. Picture courtesy of

But that was all back in the late-1800s, and most of the 1900s. In the past couple of decades, components to distribute direct electricity have been developed which are just as efficient as their AC counterparts, if not more so.

In what’s been called the “second electrical revolution”, some are saying that DC is becoming increasingly popular because it has one crucial advantage: it’s more suited to renewable energy distribution because it is more efficient, in that it loses less power in transit, over much longer distances than AC.

Meanwhile, all over the world, wind farms and solar power plants have been springing up and collecting energy from the elements for which there is little or no pollution, like there is with traditional power generation using coal, gas and oil.

This relatively clean power generation infrastructure is creating an ecosystem for an entirely new energy grid, one built on the foundations of clean energy, one build using direct current networks.

Alternating current is expected to remain the dominant medium for electricity distribution for the foreseeable future, but direct current is no longer almost an irrelevance, barely more than an insignificant novelty.

One of the key technologies which made AC popular back in the late-19th century was the transformer, which allowed voltages to be transmitted more efficiently over what were then viewed as long distances.

electricity pylons
Picture courtesy of

So the AC power grid – featuring large electricity pylons almost everywhere – was constructed over the intervening decades.

By the time the equivalent to the AC transformer was invented, DC had already lost what was called “the war of the currents”.

However, now it has been discovered that while AC is more efficient than DC over short distances – say, within a few hundred miles – over longer distances, of thousands of miles, DC is said to be more efficient.

You could say AC is the sprinter and DC is the marathon runner.

And, as pointed out in an interesting article in The Economist, this crucial ability to run long distances is what is making DC the choice of a new generation of power networks.

One of the other attractions of DC is that its power cables can be buried underground, according to another interesting article in, or even under water, so no need for often unsightly electricity pylons.

These and other advantages are resulting in more and more energy infrastructure builders to create DC networks. The Economist provides examples such as Oklahoma’s wind farm, and China’s increasingly epic DC network for its largely coal-powered energy grid.

One particularly ambitious project wants to create a DC “supergrid” to move electricity from Siberia, in northern Russia, to Seoul, in South Korea.