LINKING WIND FARMS OFFERS ENERGY WINDFALL
12.7.07 - Leído 52 veces. Enviar esta notaTracy Staedter
In the United States, each group of wind turbines, known as a wind farm, feeds its energy to the electric grid independent of other farms
WASHINGTON, U.S.; December 7, 2007.- But new research shows that if the farms were linked to each other first before delivering the electricity to the country’s grid, wind could offer steady, dependable power at a cost lower than presently available.
“It’s a really simple idea, but it’s not done because there are state and county boundaries. Different utilities are managing different farms,” said Cristina Archer, a research associate at Stanford University.
Archer and colleague Mark Jacobson published their findings in the American Meteorological Society’s Journal of Applied Meteorology and Climatology.
Wind is notoriously capricious and in the span of a few minutes can change from gusty to calm. As a result, utility companies cannot rely on wind as a primary source of power. In fact, they depend on electricity generated at coal or nuclear plants and look to wind as a third or fourth tier contributor.
And that’s a waste of clean energy, said Archer. Because when coal and nuclear plants meet demand, wind power is wasted on…well, the wind.
But if wind farms could be linked together first, said Archer, some turbines would be generating electricity when others are not, ensuring a certain amount of power all of the time.
“The main point is that the more wind farms you have on the grid the easier it is to manage their intermittency because of the canceling effects that you get,” said Jeffery Greenblatt, scientist for Environmental Defense, a non-profit organization headquartered in New York City.
In their study, Archer and Jacobson collected a year’s worth of wind data from the National Weather Service. They found that the Midwestern United States has 19 locations with average wind speeds greater than 6.9 meters per second — possibly the best area over land in the world for extracting wind power.
If wind farms were built in these locations and if some were connected to each other first, with a main transmission line connecting the group of farms to the electrical grid, the potential power could go from 0 percent of maximum capacity (available now with existing farms) to 15 to 20 percent of maximum capacity.
Over a year, coal-fired electricity plants put out their full capacity 88 percent of the time. Wind power would still be significantly lower than coal, but said Archer, that’s not the point.
Right now, utility companies look to coal and nuclear energy first and then tap into renewable energies like wind last. If wind could produce more reliable power on a consistent basis — even 15 to 20 percent of the time — the renewable energy could be first on the list.
“Don’t think of renewables as the last kind of electricity you add, but think of them first and then plan the rest accordingly,” said Archer. “It’s a vision switch.”
What’s more, if wind energy can be made more reliable, it can be traded and sold in the energy market at more competitive prices.
The biggest challenge of implementing such a plan is cost, said Greenblatt.
“We don’t pretend that renewable energy is cheap,” he said. “That’s why we need special policies to get it built.”
Such policies could, for example, put a price on carbon emissions associated with burning a fossil fuels, making coal and natural gas more expensive than wind and other renewable sources. And they would deal with sharing the decisions and cost of building the necessary transmission lines.
“We want people who care about open spaces and transmission planners and developers to all be on the same page,” said Greenblatt.
Archer and Jacobson’s plan to interconnect wind energy is not so far-fetched. A European project called Supergrid, initiated by renewable energy company Airtricity is already underway to link a series of offshore wind farms from the Mediterranean to the North Sea.
And according to the American Wind Energy Association, although wind represents less than 1 percent of the U.S. electricity generation, its potential exceeds 10 billion kilowatts annually, which is three times the amount of electricity generated from all sources today.
(Discovery News)
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