You may be aware that when electricity began to hit the mainstream, there was a rather vicious debate between Edison and (Westinghouse and Tesla) between whether the electrical grid should be AC- or DC- based. Westinghouse and Tesla portrayed AC as being more efficient than DC for local distribution (although DC is apparently more efficient over long distances). Edison argued that DC was safer, and publicly electrocuted a few animals to make his point. Additional details can be found at Wikipedia, but the end result was that Westinghouse won, and electrical grids worldwide are almost entirely AC-based.
According to The Sietch, Europe is considering switching to DC for long distance power transmission, as part of a means to integrate wind farms 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.[...]
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.
I think there is still a little matter of the expense involved in converting the grid or building an alternate grid, particularly when the existing grid is already constrained in part by NIMBYism. (Parts of Connecticut are prone to brownouts on the hottest days, because NIMBY’s have objected to running new transmission lines in their towns.)
That aside…it is an interesting idea.