Every time you use electricity in your home, from your computer to your TV (if you live in the united states or Europe) you are using AC, or Alternating current. Things like solar panels, and wind turbines produce DC, or Direct Current (edit: wind turbines can also produce AC). (the difference being that DC goes in one direction around the circuit, where as AC wiggles back and forth) That means that if you want to use solar panels, or wind turbines to power your home you have to use a little device called an inverter. An inverter changes DC to AC so that it will work with your stuff. Why, you may ask do we have AC instead of DC? Well, a long time ago a big fight happened, Thomas Edison backed DC. George Westinghouse backed AC. Westinghouse won.

There are a lot of good reasons why AC won. At the time the grid was small, you had lots of tiny power plants all over the place. Over short distances AC lines lose less electricity (to things like heat) than DC does. However with today’s modern grid (big power plants far away from the places that use the electricity) DC lines make much more sense. Over long distances DC power lines lose far less than AC. So why am I going on and on about this stuff? And what does this have to do with Europe or Wind Power? So glad you asked.

Europe is thinking of switching to DC for these long distance transfers. They are doing this because they want integrate huge amounts of wind power into the grid. The windy places in our world are often far from where people like to live (go figure, you don’t want to live in a constant gale), that means that wind farms are often far away from the people that want the energy. It is also true that the wind isn’t always blowing in all of these spots at the same time. It is however true that almost all of the time the wind is blowing in one or more of these places. In theory if you created your grid the right way, you could make sure that at every point in the day and night the wind would be “on”. This would involve using DC transmission lines to get the wind energy to the people that need it. If it’s windy in Spain, but not Germany the current goes to Germany, next week when its windy in Ireland but not Spain the energy goes to Spain and so forth.

Seems like an obvious idea, but with AC power lines the loss from moving this energy over such large distances would be astronomical, enter in DC transmission lines. Seems after all the fighting Edison once again proves to be right. DC is the best way to transport current over long distances. DC lines have the advantage when it comes to distances over 600 miles. Ever wonder why high voltage power lines are so far off the ground? It’s not just to keep you from touching them, AC wants to go to earth much more than DC does. That means the higher the voltage of the line the higher the wire has to be from the ground. Simple you say just use lower voltage, well if you want to transmit AC long distances you have to have it at very high voltage, so we are back to our original problem. DC on the other hand has no such problem.

JÃ¼rgen Schmid, the head of ISET, an alternative-energy institute at the University of Kassel, in Germany proposes a DC grid that would allow wind energy to provide up to 30% of Europe’s power supply. And because it is almost always windy at some place in Europe, this grid setup would allow wind to be used as “base load power.” Countries like the Scandinavia, the Netherlands and Germany are already building DC transmission lines. Airtricity plans to build them as well. It wants to build a “super grid” that would link offshore wind farms in the Atlantic ocean, the Irish, North and Baltic seas with customers throughout northern Europe.

Airtricity says that the project, a 2,000 turbine-strong farm in the North Sea, would cost about â‚¬2 billion ($2.7 billion). Would generate 10 gigawatts. The equivalent amount of coal-fired capacity would cost around $2.3 billion so, considering that this would not help to destroy the planet, a couple more million might be worth it.

This of course begs the obvious question, why not do the same exact thing in the United States. The eastern sea coast has an amazing wind resource, and is close to large amounts of people. The upper Midwest (places like North Dakota, Wisconsin, Michigan, etc) have been called the Saudi Arabia of wind because they are so windy, the Texas panhandle, and the California valley are also amazing wind resources, Alaska has some of the windiest places on earth. If all of these locations (and many many more that I have not mentioned) were linked together with DC transmission lines we would have constant steady wind power. Combined with large amounts of solar and geothermal this country could get almost all of its power from renewable energy without interruptions when the wind wasn’t blowing in any one area.



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