Thursday, July 29, 2010

How to make use of wind energy

In the quest for alternate energy sources wind has more promise than solar. CalFinder. Earth is bombarded with solar energy 24 hours per day; it's just a matter of capturing it and converting it to useful form at the right place and time. Wind has big problems with place and time of day.

The big wind areas are in the west and offshore in the east. The Kennedys are using all their power to make sure their royal view is never marred by something to generate all the power they use. So rule out the East offshore. All the energy captured in the West has to be transmitted. Of course the same people who say our salvation will come from green energy fight tooth and nail against any company that tries to build transmission lines for the wind energy.

And the wind blows at certain times of day, not much at night. So when people are getting up on the populous east coast the Sun is not yet up and spinning the turbines in Wyoming. And it is erratic as well - gusting...

Creative people are working on these problems. And they can only invest in solutions if they can make a profit. They are working on Storage ideas.

NY Times

In New York and California, companies are exploring electrical storage that is big enough to allow for “arbitrage,” or buying power at a low price, such as in the middle of the night, and selling it hours later at a higher price. In the Midwest, a utility is demonstrating storage technology that can go from charge to discharge and back several times a minute, or even within a second, bracing the grid against the vicissitudes of wind and sun and transmission failure. And in Texas, companies are looking at ways of stabilizing voltage through battery storage in places served by just one transmission line.

... “you can’t do that without batteries of some sort,” said Peter Rosegg, a spokesman for the Hawaiian Electric Company.

His company has agreed to buy electricity from a wind farm on the northern shore of Oahu, where the Boston-based power company First Wind has just broken ground.

The spot is one of Hawaii’s best wind sites, Mr. Rosegg said, but the supply is gusty and erratic. What is more, it is at the farthest point on the island from the company’s main load center, Honolulu, and does not even lie on its high-voltage transmission backbone.

So the 30-megawatt wind farm, which will have enough power to run about 30 Super Wal-Marts, will have Xtreme Power of Austin, Tex., install a 15-megawatt battery.

Computers will work to keep the battery exactly half-charged most hours of the day, said Carlos J. Coe, Xtreme Power’s chief executive. If the wind suddenly gets stronger or falls off, the batteries will smooth out the flow so that the grid sees only a more gradual increase or decrease, no more than one megawatt per minute at some hours of the day.

The Hawaii installation is designed to succeed at a crucial but obscure function: frequency regulation. The alternating-current power system has to run at a strict 60 cycles per second, and the battery system can give and take power on a micro scale, changing directions from charge to discharge or vice versa within that 60th of a second, to keep the pace steady.

No comments: