Hydro project ramps up south of Juneau

Dam could be built in 2007, powerhouse in 2008

Posted: Wednesday, January 18, 2006

Construction could be launched in March on a privately financed hydroelectric project supplying power to the Greens Creek Mine and Juneau.

A major component of the Lake Dorothy Hydroelectric Project - a 20-foot diversion dam on Bart Lake supplying a powerhouse on Taku Inlet, about 16 miles southeast of Juneau - will cost roughly $48 million to build.

"We're trying to get started in March," said Corry Hildenbrand, president of Lake Dorothy Hydroelectric. If so, the project could be completed in 2008.

A contract to build a 1.8-mile road to the lake will be awarded in February, Hildenbrand said.

The road will take a full construction year to build. The dam could be built in 2007 and its powerhouse and substations in 2008. Hildenbrand said that the dam will not raise the lake level over its natural high water mark.

The Lake Dorothy hydro project was announced in 1996 and approved in 2003. But Lake Dorothy Hydroelectric had to revise its plan for Bart Lake in 2005, after discovering a geological hazard.

The project's developers quickly latched onto another project design.

"There's really no alternative to building (the hydro project)," said Tim McCloud, president and general manager of the Alaska Electric Light & Power Co.

It's the only new hydro project planned for Juneau's future needs at this time, company officials said. Power generated from the project will flow through a submarine cable to AEL&P's local power grid.

For now, the 14.3-megawatt hydro project likely will have a zero to minimal effect on Juneau electrical rate payers, McCloud said. That's because the Greens Creek mine on Admiralty Island will initially purchase up to 90 percent of the surplus power generated from the new project.

"If we didn't have the mine to buy all the surplus energy, we'd have a substantial increase in rates to the customers now," McCloud said.

If and when energy demand grows in Juneau, the power will be diverted from Greens Creek to Juneau, according to an agreement with the mine, Hildenbrand said.

A similar arrangement will take effect once Hoonah is linked to AEL&P's power grid.

"Hoonah will also become priority over Greens Creek," Hildenbrand said.

Over the long term, Juneau rate payers can anticipate a cost savings due to the hydro operation, McCloud predicted. But AEL&P's rate predictions depend on the project going as planned.

The hydro project doesn't prevent other energy-related costs that affect electricity bills, such as insurance, from rising in the future, McCloud warned.

Lake Dorothy Hydroelectric, received federal approval in 2003 to tap Bart Lake and Lake Dorothy, using underground tunnels and a large pipe, for electrical power.

Due to geological hazards discovered by engineering consultants, the company had to scratch its plan for the lake tap under Bart Lake. It now plans to replace an existing debris dam on Bart Lake with a 20-foot-high concrete-reinforced dam, and pipe the water downstream to a powerhouse on the shore of Taku Inlet.

The company is still getting its final plans signed off by the U.S. Forest Service and the Federal Energy Regulatory Commission. The plans include a $70,000 settlement with the Alaska Department of Fish and Game to compensate for lost habitat for non-native brook trout living in Lower Dorothy Creek.

The stream flow needed in the creek to ensure the survival of the trout would make the hydro project uneconomical, according to the settlement.

Lake Dorothy Hydroelectric is also working with the Forest Service on timber removal in its construction zone, and it needs to finalize its financing plan, company officials said.

Finalizing all the plans is "pretty high on our list of priorities," said Pete Griffin, Juneau district ranger for the Tongass National Forest.

In the future, the developers plan to drill a tunnel to tap nearby Lake Dorothy, which has twice the hydroelectric potential of Bart Lake.

That 30-megawatt project is likely 20 years down the road, Hildenbrand said.

"It's there for the future," Hildenbrand added.

• Elizabeth Bluemink can be reached at elizabeth.bluemink@juneauempire.com.

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