Permit for Juneau Hydropower dam south of Juneau on Planning Commission agenda Tuesday

280-foot-wide, 111-foot-high dam at Sweetheart Lake part of project envisioned to supply renewable energy as far north as Berners Bay

An overview of the Juneau Hydropower project. (Image by Ameresco Inc.)

By Mark Sabbatini

Juneau Independent

Approval of a 280-foot-wide, 111-foot-high hydroelectric dam at a lake south of Juneau, along with supporting infrastructure for a renewable energy project in the works for the past 15 years, is set to be considered by the Juneau Planning Commission on Tuesday.

The conditional use permit will authorize the dam and infrastructure for the Juneau Hydropower project that envisions supplying renewable energy extending from the lake about 30 miles south of Juneau to the Kensington Mine in Berners Bay about 45 miles north of town.

The project is expected to cost between $240 million and $270 million, with a goal of beginning construction next year and completing it within two years, said Duff Mitchell, managing director at Juneau Hydropower Inc., in an interview Monday.

"We're adding 3% of all the total transmission in Alaska," he said. "This is a great, profound piece of infrastructure for Juneau. It opens up land and other potential development in the borough."

The Planning Commission documents for the project state infrastructure besides the dam includes "a powerhouse, penstock, transmission lines, access roads, and a caretaker’s residence (to) be constructed to support operations and maintenance."

The Juneau Hydropower plant is designed to use the lake‘s natural hydrology to generate about 19.8 megawatts of electricity transmitted through a newly constructed transmission line that will connect with existing hydroelectric infrastructure, according to a background summary by CBJ’s Community Development Department.

"A key component of this project is the extension of electrical service from the current grid terminus at the Point Lena Substation," the summary notes. "The new infrastructure will carry electrical transmission eastward to Cascade Point, Echo Cove, and ultimately to the Kensington Mine located in Berners Bay. This extension aims to replace diesel-generated power currently used in these remote areas with clean, renewable energy, reducing greenhouse gas emissions and supporting regional energy resilience."

A conditional use permit for the Sweetheart Lake Hydropower Project was issued in 2016 by the Planning Commission, but expired in 2018 because a required building permit for the project was not issued by then, according to CBJ.

The current project is a partnership between Juneau Hydropower and Ameresco Inc., an engineering services company based in Framingham, Massachusetts.

Questions have been raised by some local officials about the scope and potential customers for the project. Mayor Beth Weldon told KTOO earlier this year she is skeptical that Juneau Hydropower can build a reliable customer base and Alec Mesdag, CEO of Alaska Electric Light and Power, said he doesn’t believe it is financially viable.

The Community Development Department’s report recommends the Planning Commission approve the permit, with two conditions attached. One is requiring Juneau Hydropower to provide photographic evidence a landform barrier is in place before a Certificate of Occupancy is issued. The other is obtaining a Flood Zone Development Permit before a building permit is issued.

The Planning Commission meeting is at 6 p.m. in the Assembly Chambers and can also be seen online via Zoom.

• Contact Mark Sabbatini at editor@juneauindependent.com or (907) 957-2306.