Bounteous wind power swamping electric grid

PORTLAND – On the afternoon of May 19, in a single chaotic hour, more than a thousand wind turbines in the Columbia River Gorge went from spinning lazily in the breeze to full throttle as a storm rolled east out of Hood River.

Suddenly, almost two nuclear plants worth of extra power was sizzling down the lines – the largest hourly spike in wind power the Northwest has ever experienced.

At the Bonneville Power Administration’s control room in Vancouver, Wash., it was too much of a good thing. More electricity than its customers needed. More than the available power lines could export from the region. And more than the grid could readily absorb by ramping down generation at the region’s network of federal dams.

So the edict went out: Feather your turbine blades; slash output.

It was an unwelcome instruction for wind farm owners, whose economics depend on generating electricity whenever possible. Yet it’s one likely to go out with increasing frequency.

During the last three years, the building boom spawned by green energy mandates in Oregon, Washington and California doubled the generation capacity of wind farms in the region. By 2013, it’s expected to double again.

That seems like great news. Plenty of carbon-free energy with no fuel costs. Jobs. Property taxes.

In the real world, however, the pace and geographic concentration of wind development, coupled with wild swings in its output, are overwhelming the region’s electrical grid and outstripping its ability to use the power or send it elsewhere.

In theory, better coordination of the balkanized grid operations around the West could help solve the problem, reducing costs, eliminating bottlenecks and solving scheduling conflicts that plague the system today.

In practice, however, those efforts have often stalled at the planning stage – the victim of risk-averse engineers, utility managers or public utility customers worried about seeing their rates increase.

Ultimately, the solution is to beef up or build new power lines, said Randy Hardy, a Seattle-based energy consultant. But that’s a five- to ten-year proposition, involving what to build, where to put it and who pays.

“We have a next-year problem,” Hardy said, “or maybe a this-year problem.”

Only 15 percent of the electricity generated by wind farms in the Northwest goes to the public utilities that buy power directly from BPA, which sells power from federal dams in the Columbia Basin. But the federal power marketing agency manages three quarters of the region’s high voltage transmission system, including the sections serving most of the region’s wind farms.

That makes it BPA’s job to balance their up-and-down output, blending it with other sources of power so total generation at any given time matches total demand.

The dams are great for the job – operators can adjust water flows through the turbines to help offset variable wind output – but only within limits.

When the wind blows harder than forecast, particularly during periods of high spring runoff at the dams, operators face the opposite problem. They can’t bypass the dam turbines to lower hydro generation, because dumping too much water over the spillways harms fish.

So the other option is to cut wind-farm generation.

At the current rate of wind development, says Elliott Mainzer, BPA’s director of strategic planning, the region’s system of dams and power lines will start running into consistent operational problems around 2013, when wind generation in the agency’s territory reaches total capacity of some 6,000 megawatts.

The solution, most experts believe, lies in better coordination of power plants across the West, more efficient use of existing power lines and some expansion of the grid.

Building new transmission, though, is an uphill battle. New lines often require rights of way through sensitive habitat and private property. And they are phenomenally expensive.

There’s also an effort to get more out of existing lines. The capacity of power lines linking Oregon and California, for instance, is completely booked long term. But on a day-to-day basis, utilization can be lower than 50 percent.

Part of the problem is that utilities buy more capacity than they need and hoard it for emergencies. If that capacity can be freed up, BPA estimates the lines could transfer 10 to 15 percent more power.