New energy sources could easily overload power network 

There’s a big obstacle to creating a shiny techno-green future by adding wind, sun and wave energy to our power system: the grid.

The nation’s electric power transmission system, aka the grid, could be imagined as an overworked tangle of fraying household wires repeatedly spliced together by your grandfather, who refuses to call the electrician. It is based on century-old technology and, from a modern management perspective, is dumb.

Often, it’s likened to the nation’s highway system. But one local utilities executive said that is wishful thinking.

“More like a collection of New England country lanes,” said Roger Garratt, resource acquisition manager for Puget Sound Energy.

Today, these country lanes are increasingly potholed, getting hit by massive snarls of traffic, with more vehicles every day and drivers demanding even higher speed limits.

Over the next decade, nationwide power consumption is expected to increase 19 percent while transmission capacity on the grid is projected to increase 7 percent.

The strain on grandpa’s grid already is beginning to show.

The largest power blackout in U.S. history, on Aug. 14, 2003, began when a single power plant in Ohio shut down. Power lines overheated, short-circuited and led to an outage affecting 50 million people in the northeastern U.S. and Canada. The blackout is estimated to have cost as much as $10 billion.

Last winter’s windstorm here, which killed 15 people, cost the region about $10 million and knocked out power to 1.5 million people across the Pacific Northwest, was another reminder of just how fragile is our connection to the power grid.

Initiative 937, which requires utilities to use more renewable sources of energy, will add to the demand and to the complexity of managing the grid. Wind and solar energy, for example, are intermittent sources that will feed unpredictably into the power flow. One effect of I-937 will be like introducing a fleet of cars that routinely slow down or stop on country lanes.

Such problems are manageable, experts say, but only if we improve and expand the grid as we expand energy generation.

“We’re already trying to deliver more energy than the existing infrastructure can handle,” said Jud Virden, an energy systems expert at the U.S. Department of Energy’s Pacific Northwest National Laboratory in Richland.

“We can just try to add more transmission capacity, more high-voltage power lines, to expand the grid, but that’s expensive, and it’s getting harder to do,” said Rob Pratt, Virden’s colleague and director of the lab’s activities in a grid-improvement project known as GridWise.

A better, approach, Pratt and Virden said, is to make the grid smarter.

The GridWise project is one of several national efforts to improve management of the grid for both producers and consumers. It could do for the power grid what the Internet did for the communications system.

“Right now, the grid is operated by managers who respond to issues or challenges directly and with a feedback time on the scale of minutes,” Pratt said.

Managers faced with power overloads or energy deficits turn power lines on or off to try to keep the grid’s flow in balance, he said.

GridWise sensors would automatically monitor electricity flow and respond to changes in seconds rather than minutes, Pratt said.

“What we want to do is manage the grid in real time to optimize its efficiency,” Virden said.

Though still largely experimental, he said, some of the automated monitoring equipment is being tested on the grid.

Pratt and Virden are also involved in the “Grid-Friendly Appliance” project, which puts small circuit boards in appliances so they can respond to changes on the power grid. If the grid is under stress, the appliances turn off or advise the user to wait before using them.

“If all appliances had these boards in them, it would smooth or flatten out power demand at the consumer end by quite a bit,” Pratt said.

Puget Sound Energy’s Garratt said he’s enthusiastic about projects like GridWise, but said the grid still must be expanded. “We simply have to have more, new investment in the infrastructure, and we need to get moving on this pretty soon,” he said.

Wind power is the most viable renewable energy source in this region, Garratt said, and most of it will be generated east of the Cascades.

“And most of the demand will be where most of the population is, along the I-5 corridor,” Garratt said. “We have to get that energy across the Cascades somehow. With the existing system already at transmission capacity, that will be a challenge.”

By Tom Paulson

Seattle Press-Intelligencer

14 August 2007