Wednesday, December 14, 2005

Wind Power in Spain

Continued from Page 6

Former IDAE director general Garcia said: "The whole system has improved a great deal, including how it deals with peaks in the winter and the summer. In the peaks of the summer, wind energy has represented sometimes up to 15 to 16 percent of the energy distributed on the grid. And the stability of the system has improved a great deal as well."

Beyond the variability of the resource, grid issues remain. Traditional power sources are large power plants, sited relatively close to the demand. Current transmission lines reflect this reality. Wind turbines, however, may incorporate a number of smaller generators (an entire wind farm may have a few hundred megawatts of power, while a new nuclear plant may contribute a thousand megawatts). In addition, wind turbines may be farther from population centers (such as proposed wind farms in the Midwestern United States) that necessitate upgrades and changes to the transmission lines.

In Spain, this issue has presented challenges as well. The Spanish grid has had problems absorbing the amount of wind power generated, according to Garcia. Upgrades to the transmission system are a top priority, according to the Spanish government, in reaching the stated goal of 20,000 megawatts by 2011. In particular, reinforcing and strengthening the power-sharing mechanism between Spain and France—and thus Spain and the rest of Europe—is of primary importance. When there is an energy need in France, Spain exports power to meet that need, and vice versa. But the transmission lines between the two countries are not yet adequately reinforced to support this two-way movement to its full capacity.

Because a great amount of wind power is generated in northern Spain, a stronger connection to France and the rest of Europe to better manage power surges and dips is paramount.

"It's similar to the situation of Denmark and Germany," said Garcia. "When wind is blowing in Denmark, they export it to Germany. And when wind doesn't blow in Denmark, Germany exports energy to Denmark. The European energy systems have to be interconnected."

Another challenge that needs to be addressed before the country can reach these ambitious goals, said Garcia, is creating a control center for all the wind farms around the nation, similar to the control center that exists for conventional power plants. Also, the technological challenges addressed by the turbine companies, such as technologies that deal with minute dips in voltage from the grid, will further the ability to meet the 20,000 megawatt goal.

Another factor that could increase efficiency is more-detailed prediction. Meteorological information allows electric companies and wind-farm operators to predict with a high level of accuracy when wind will pick up and slow down. With this hourly information, electric companies know when to expect more power from wind farms, and when to pick up the slack from other sources.

To reduce the inaccuracy in wind-power predictions, Spanish wind farm operators are joining with system operators to determine the best practices for implementing improvements in predictions. According to Alberto Ceña, director of the Spanish Wind Energy Association (AEE), "Every day wind farms are offering power to the market. They need to reduce deviations—the difference between forecast and the real production."