The increasing deployment of renewable energy will have far ranging impacts for the electrical grid, ranging from the need for energy storage to a more flexible demand side response. But one area where it could drive infrastructure shifts involve long distance electricity transmission and the implementation of more direct current (DC) transmission rather than alternating current (AC) transmission, which currently dominates the grid.

The War of Currents between George Westinghouse and Thomas Edison has been well documented.  Edison had patents that favored DC technology but Westinghouse wound up financially backing the development of an AC power network, which is what we have today.

But DC has been getting more attention in the last few years for a few reasons. Most AC transmission is built with overhead lines, which are unpopular with municipalities. When AC is placed underground, a charging current is required to feed that cable, which effectively limits how long you can underground an AC cable.

Those problems don’t exist for DC transmission, which is effective at transmitting large amounts of power underground over long distance. But one thing that’s held DC transmission back, aside from the de facto state of the AC grid, is that breaking the circuit on DC lines has been a challenge and requires very fast and reliable circuit breakers.

Stepping into this picture has been the growing deployment of renewable energy, including wind, solar and hydro. Unlike coal or natural gas power plants, this energy has to be harvested from locations that typically are not where you need to use the power. They require transmission over long, stable lines. So a conversation has begun about the potential for a renaissance in DC power.

The need for long distance electricity transmission is particularly evident in places like China where a great deal of wind power has been deployed but has not yet been transmitted and grid connected. Another benefit of DC transmission is that it involves two conductors rather than three for AC, which results in less material needed. Finally, there’s also a small argument that DC is optimal for some renewable sources because for some generation like solar, the current coming out of a panel is actually DC. Today micro-inverters are needed to smooth the conversion of DC current into grid acceptable AC current.

It’s improbable that we’ll have the sort of current wars that ended the 19^th century. But we are likely to see a greater openness to DC current. For example, we’re already seeing DC power supplies for the data center from companies like Validus DC, which was acquired by global power specialist ABB in 2011. DC power supply supporters point to less power losses in the data center owing to fewer AC/DC conversions.

As ABB’s North American President of its Power Systems Division Anders Sjoelin put it to me recently, “I don’t think it’s AC versus DC. Today it’s more AC and DC. It’s seen as a compliment.” He added, “there’s controllability with DC. You can dial in how many megawatts you want to move from point A to point B. And with renewables you don’t have the choice of putting the power plant where you want it. That drives the transmission need.” ABB has high voltage direct current (HVDC) technology that is optimized to transport large volumes of power.

With DC transmission, we’re seeing unprecedented volumes of power being transmitted owing to improvements in technology. One line in China is moving 6400 megawatts and there’s talk of 10,000 megawatts on a single line with two large conductors. The largest solar power farm in the world, the Blythe Solar Power Project in California outputs 1,000 megawatts and a typical nuclear power plant would be capable of between 800 and 1000 megawatts. A line that could carry the equivalent of 10 nuclear or solar plants opens up the possibility of transmitting large amounts of renewable  energy from remote locations.

The deployment of renewables will have far ranging effects, not just in the need for the grid to deal with the intermittency of sources like wind and solar. But potentially in the very way that the power itself will be moved around in order to remake the grid.