20th Century System Meets 21st Century Resources

By David Wagman, Chief Editor

Every year power plants having almost 1,000 GW of generating capacity provide electricity to more than 140 million customers across the United States. All that power is sent across 158,000 miles of transmission lines and another 1 million miles of local distribution lines, no one is really certain of the exact number.

What we do know for certain is this: the transmission link is absolutely vital to connecting power plants with consumers. And transmission is also where some of the toughest problems exist when it comes to bringing more renewable energy resources to market.

I traveled to Texas in late February for our annual renewable energy conference and visited the Electric Reliability Council of Texas (ERCOT). There I sat down Joel Mickey, director of grid operations, and spoke with several control center operators. I also met with Barry Smitherman, chairman of the Texas Public Utilities Commission, Jon Wellinghoff, chairman of the Federal Energy Regulatory Commission, and Martin Gross, president of ABB Power System’s North American operations, all of whom addressed the conference.

Texas is a good place to examine the transmission issue afflicting North America. As the state’s main grid operator, ERCOT manages the flow of electricity across the grid for most of Texas and around 85 percent of its electric load. Texas is the smallest of three grid interconnect regions in the U.S. The other two are known as the eastern interconnect and the western interconnect and split the country roughly right down the middle.

At the ERCOT control center in Taylor, Texas, not far from the state capitol in Austin, grid controllers work to ensure enough power is being generated and moved across transmission lines to serve consumers.

Texas has some of North America’s best wind resources. Just last month the state set a new record for wind generation when about 19 percent of the electricity on the state’s grid was supplied by wind turbines. That equated to a total of 6,272 MW.

Developers have built more than 9,000 MW of wind capacity in Texas. And that capacity, when it’s available, is among the first to be dispatched because it is priced close to even below zero, after accounting for various tax incentives.

But there’s a problem. Most of the wind is in the far western part of the state. Population centers like Dallas, Ft. Worth and Houston are in the eastern part of the state.

That means the problem in Texas—and at a much larger scale across North America—is this: How to move large amounts of intermittent renewable energy from one location to another? And how do grid operators plan for and manage that supply? Are the right tools—and the right rules—in place to successfully integrate wind into the resource mix? Can the 20th Century grid adapt to accommodate 21st Century energy resources?

Texas is coming up with some answers. For one thing, ERCOT uses a wind forecasting tool developed by AWS Truewind to help schedule day-ahead resources. When I visited, ERCOT was just deploying a new tool to help it predict ramping events. In one test the software accurately forecasted a 2,000 MW downward ramp wind event, followed by a 15-minute lull and than a 2,000 MW recovery. Having reliable and accurate forecasting tools in place is critical to successfully deploying increasing amounts of intermittent renewable resources.

For another, Texas is making good on its Competitive Renewable Energy Zone (CREZ) concept, which is aimed at building transmission capacity before new wind energy resources are built so the new capacity can be brought to market more rapidly. The CREZ initiative, the subject of our January 2007 cover feature story, is now closer to being implemented. It’s one reason why Barry Smitherman of the PUC likes to boast that a politically “red” state like Texas can be more “green” than many “blue” states (California, take note).

The CREZ project suffered a blow in early March when a district court judge in Texas reversed a PUC order awarding billions of dollars of transmission projects. The court sided with the City of Garland that regulators failed to properly consider public power entities like Garland for the projects.

Garland argued it could handle the power line construction at a lower cost than the companies awarded the projects. It said, and the court agreed, that a city enjoys certain tax advantages and can borrow funds at better interest rates. Those lower costs could mean lower costs for ratepayers. Texas regulators now must rethink the contracts in light of the Texas court ruling.

Sharryn Harvey, our Online Editor, reports elsewhere in this issue on transmission topics related to expanding renewable resources into Northeastern U.S. markets. And an exclusive video newsmagazine piece on transmission is available for viewing online at the Power Engineering magazine page at www.power-eng.com.


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