August 11, 2013

U.S. electrical grid still vulnerable

Ten years after a big blackout, changes in how electricity is produced raise new concerns about the reliability of the grid.

By KANTELE FRANKO and JONATHAN FAHEY The Associated Press

(Continued from page 1)

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The Empire State Building towers over a darkened New York City skyline just before dawn on Aug. 15, 2003, the day after a tree branch in Ohio touched a power line and set off outages affecting 50 million people. Utilities and analysts say that changes made in the aftermath make a similar outage unlikely today, but that the U.S. electrical grid faces new stresses.

The Associated Press

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Customers wait in line to buy essential items at a grocery store in Grosse Pointe, Mich., after the blackout of August 2003.

Last year was particularly good.

Not including extreme weather events, major transmission lines caused power losses only twice in 2012, after averaging nine instances annually from 2008 to 2011.

The report says transmission lines have been functioning normally and available for use an average of 99.6 percent of the time, not including for planned outages, since tracking began three years ago.

Most outages residents experience stem not from the bulk system, but from smaller failures in distribution systems managed by local utilities and regulated by states.

Not including storm-related outages, the average U.S. customer goes without power 1.2 times annually for a total of 112 minutes, according to PA Consulting Group.

COAL AND NUCLEAR DECREASE

The bulk power system is changing, a result of the declining use of coal and nuclear power and the rising use of natural gas and renewable power.

One-sixth of the existing coal capacity is projected to close by 2020, much of it at small, inefficient units in the Ohio River Valley, the Mid-Atlantic and the Southeast, according to the Energy Information Administration. The permanent closure of four nuclear reactors in California, Florida and Wisconsin was announced this year, and reactors in New York, Vermont and elsewhere may also close.

Plant shutdowns mean there's less of a cushion in electrical capacity when power demand is high or problems arise.

Shutdowns also create pockets of transmission congestion or regions where power is scarce. Both situations drive up power prices for customers, make the grid less stable and present planning challenges.

"That is a new stress that we hadn't thought about" a decade ago, said Scott Moore, vice president of transmission engineering and project services at American Electric Power, one of the nation's biggest utilities.

The reliability report raises concerns about the Texas grid, one of the three major U.S. grids, where the amount of wiggle room in capacity is expected to dip below targeted minimum levels.

Growing reliance on natural gas-fired generation also creates weak spots.

For example, utilities that supply natural gas to customers for heat can typically take all the gas they need from pipelines before any excess goes to electricity generators.

In regions with limited pipeline capacity, such as the Northeast, planners say there might not be enough gas to heat homes and generate electricity simultaneously during a cold snap.

"In the winter there could be a significant and sudden unavailability of power," said former Vermont regulator Rich Sedano, who directs the Regulatory Assistance Project, a nonprofit advisory group. "It's critical that this emerging threat to the grid is addressed."

ITC Holdings' Joe Welch argues increased spending on the grid in recent years reflects how quickly it is aging, not a concerted effort to modernize or strengthen it.

"We've done paltry little," he said.

POSITIVE CHANGES

But planners say changes made since 2003 at least give grid operators better control and add flexibility.

"We can't redirect hurricanes or prevent every cyberattack, but we can focus on resilience," said Terry Boston, president of PJM Interconnection, a regional transmission organization serving 13 states.

For now, there appears to be enough electricity capacity to meet demand, which has remained relatively flat since 2005.

The nation's natural gas plants aren't fully used, and wind, solar and other renewable generation have been built to comply with state renewable power mandates.

"Many feel there is a very long fuse here, and there may not be a bomb at the end of it," Sedano said.

 

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