We know we have a problem with carbon emissions mucking up the climate.

But switching over to renewable energy isn't that easy. For one, many places that are good for making renewable energy -- windy plains or sunny deserts -- aren't necessarily near big cities, where the energy is needed.

And what happens when you try to transport energy hundreds of miles from the energy source to the big city? It loses some of its power. At least today's dominant form of power, alternating current (AC), does.

But Thomas Edison championed direct current (DC), and it looks like he might be vindicated.

Up till now, DC was not used on large power grids because of the energy it loses when carried over long distances and for fear it would be prone to catastrophic breakdowns. (More on that below.)

But a new type of power, high-voltage DC, or HVDC, could carry power long distances with minimal loss -- and a new device called a hybrid HVDC breaker would help prevent those huge breakdowns.

Developed by Swiss power technology company ABB, the breaker has only been tested in the lab, but ABB claims the hybrid HVDC breaker will make possible "the grid of the future," which National Geographic News describes as "a massive, super-efficient network for distributing electricity that would interconnect not just nations but multiple continents."

What the hybrid HVDC breaker is and why it's important

The thing about HVDC, or any direct current for that matter, is that, unlike AC, it's always on.

That makes it much trickier to regulate.

"When you have a large grid and you have a lightning strike at one location, you need to be able to disconnect that section quickly and isolate the problem, or else bad things can happen to the rest of the grid," such as a catastrophic blackout, ABB chief technology officer Prith Banerjee told Nat Geo News. "But if you can disconnect quickly, the rest of the grid can go on working while you fix the problem."

This new breaker can redirect and shut down a current using a series of both mechanical and electronic circuit-breaking devices. And it can do that with surges equivalent to what a one gigawatt power plant (big enough to serve one million U.S. homes) might generate -- all in less time than the blink of an eye.

What the grid could look like

So, back to the renewable energy part.

The amount of energy that renewables can now provide is a fraction of what we need because the place where the energy is generated is so far from where the energy is needed. But Narain Hingorani, a fellow with the Institute of Electrical and Electronics Engineers who researches power-transmission, says that hybrid HVDC breakers could help us capitalize on renewable energy.

As Nat Geo reports:

HVDC cables could be laid along the ocean floor to transmit electricity from floating wind farms that are dozens of mile offshore, far out of sight of coastal residents. HVDC lines equipped with hybrid breakers also would be much cheaper to bury than AC, because they require less insulation, Hingorani says.

It could also make viable wind farms and solar installations in the Midwest and Rocky Mountain area, and HVDC cables could be run underground.

Related on SmartPlanet:

via: National Geographic News

photo: HVDC transmission lines in New Zealand (Paul Moss/Wikimedia)

This post was originally published on Smartplanet.com