Jul 03 - Billings Gazette, The

The clean, green power from the Judith Gap Wind Farrn that debuted last fall has been more intermittent than anticipated.

And that is causing problems for NorthWestern Energy; the utility that must balance supply and demand on its transmission lines.

"It's more variable initially than we anticipated. But remember the facility has just gone through startup and there is a shake- down period," said David Gates, vice president of wholesale operations.

In April, the Western Electricity Coordinating Council in Salt Lake City sent a letter to NorthWestern saying that its transmission system may have fallen 3 percent short of its minimum control performance standards of 90 percent. WECC, an organization representing 44 power companies, is part of a voluntary nationwide system to improve reliability on the nation's transmission grid.

WECC spokesman Kwin Peterson said the letter is preliminary and carries no sanctions. The facts must be reviewed and proven, a process that can take three months.

"This is unconfirmed and ordinarily this information isn't even made public," he said.

The council sends out about a dozen of these letters every three months, he said.

Blowin' in the wind

Joel Schroeder worked as project manager for Invenergy Wind LLC's Judith Gap project, the largest of the company's four wind farms. Reached at company headquarters in Chicago, Schroeder said wind is by nature intermittent.

"If you have a storm move in and the wind picks up, that will boost production, or if you have the opposite and the wind drops out, you'll lose power," Schroeder said. "It's completely dependent upon the wind."

Everyone knows wind power is variable and that other backup power from coal or hydro or natural gas is needed to fill in the calm times.

However, the hourly ups and downs are harder to manage than expected, Gates said.

The wind's blowing and in that hour, the output goes from 20 MW (megawatts) to 80 MW," he said. "The average is 50 MW, but as control operator we have to manage that move from 20 to 80 MW (on the transmission lines).'

He said the utility expects performance to improve at the wind farm.

Power balancing

You can store water behind a darn, But you cannot store electricity, and that fact creates lots of challenges for delivering power and pricing power.

Engineers may have more elegant explanations, but you can think of a power transmission fine as a teeter-totter.

To keep the board level, the supply of power sitting on one side must balance the demand sifting on the other side.

When there is too much supply, the utility has to sell power right now. When demand outweighs supply, the utility must buy more power right now.

Long-range power contracts; that run for years are relatively inexpensive. But, like shopping at a convenience store, buying power on the spot market costs more, often far more.

So variability at the Judith Gap project is costing NorthWestern's consumers more, they just don't know how much yet.

Green power is cool

The Montana Legislature mandated that NorthWestern buy 15 percent green power by 2015.

As part of the move to alternative power, Invenergy Wind built the Judith Gap Wind Farm with 90 turbines towering 260 feet into the air. With approval of state regulators, NorthWestern Energy agreed to buy all of this Montana wind power for the next 20 years.

With output ranging from 135 megawatts to 150 megawatts, Judith Gap provides about 7 percent of the electricity NorthWestern needs to serve its 316,000 electrical customers. Another 70 percent comes from PPL Montana, which bought Montana Power's dams and coalfired properties.

However, after two PPL contracts expire in July 2007 costs are expected to rise significantly, especially in view of Thursday's ruling in Washington, D.C.

The ruling said that PPL does not exert monopoly control in Montana and can charge market rates or the highest price the market will bear.

Future wind farms

On May 7, more than 30 energy developers, power company representatives and rural electric cooperative executives met in Helena with Gov. Brian Schweitzer's staff to discuss Montana's energy future.

One topic was how to build more wind farms, yet keep the transmission lines balanced.

Dave Wheelihan, chief executive of the Montana Electric Cooperatives Association, said the gist of that part of the conversation was that NorthWestern has had to buy more short-term power than expected to balance Judith Gap.

"You can go out and contract for it, but the pricing will be interesting," Wheelihan said.

He said the utility has purchased another 15 megawatts of incremental power from Avista Energy to balance the load.

NorthWestern executives said that extra power is being paid for through retail customers rates, Wheelihan said. Wholesale customers like his members, the rural electric cooperatives, aren't bearing the extra cost.

NorthWestern Energy is paying $31.75 per megawatt-hour for the Judith Gap power. The price for buying backup power before this extra demand was estimated at another $5 to $9 per mwh.

With several proposed power plants, wind farms and transmission lines on the drawing board for Montana, the key questions remain: What will they cost and who pays?

Now a third question of how to build more wind power while keeping regional transmission lines reliable appears to be more challenging than earlier thought.

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