The federal deadline to begin building the Sweetheart Lake hydroelectric project south of Juneau, Alaska, passed on Sept. 8 with the developer's request for more time still pending. The Federal Energy Regulatory Commission published notice of Juneau Hydropower Inc.'s request on Sept. 4, opening a public comment period that closes Oct. 1 at 5 p.m. Eastern Time.

The company filed the request on May 18 and supplemented it three times through late July, according to the notice, which describes the project as unconstructed. The request would move the construction start deadline to Sept. 8, 2028, and push the completion deadline from Sept. 8, 2029, to Sept. 8, 2031. It relies on a new federal law, signed May 11, that lets FERC grant extra time to older hydropower licenses that have used up their standard extensions.

For Juneau, the stakes involve power supply and fuel use. The 19.8-megawatt project would raise the borough's electricity supply by about 20%, according to KTOO, and would serve Coeur Alaska's Kensington gold mine, which burns roughly 4.5 million gallons of diesel a year.

Ten Years After the License

FERC licensed the project on Sept. 8, 2016. Under Section 13 of the Federal Power Act, licensees must begin construction within two years, and FERC can extend that window by up to eight more years, for a total of 10. For Sweetheart Lake, that limit ran out on Sept. 8, 2026.

Congress changed the rules this spring. Public Law 119-90, sponsored by Sens. Steve Daines of Montana and John Fetterman of Pennsylvania, lets FERC extend construction start deadlines for projects licensed before March 13, 2020, by up to six more years in two-year steps, after reasonable notice and "for good cause shown." If an extension is granted, the law says the new period begins on the date the previous extension expired.

The law also lets FERC reinstate licenses whose construction deadlines expired after Dec. 31, 2023, and before the law was enacted. Sweetheart Lake's deadline falls outside that window because it passed after the law was signed.

According to the notice, this would be the first two-year extension granted to the project under the new law, leaving room for up to two more if the company later seeks additional time.

The filing is not a new licensing proceeding. The project already holds a license backed by a 2016 final environmental impact statement, and in 2025 the U.S. Department of Agriculture's Rural Utilities Service moved to adopt that FERC analysis for its own funding review after concluding the work was "still current and sufficient."

Power, Diesel, and a Remote Mine

The facility would draw from Lower Sweetheart Lake, about 30 miles south of Juneau in the Tongass National Forest, and would occupy about 2,058 acres of federal land managed by the U.S. Forest Service. It is designed to produce an average of about 116,000 megawatt-hours of electricity a year.

The licensed design includes a 111-foot-high concrete dam at the lake's natural outlet and a tunnel carrying water to a powerhouse near sea level. Project contractor Ameresco says the plans also include a battery storage system and more than 40 miles of high-voltage transmission infrastructure, including about 8 miles of undersea cable across Gilbert Bay. The anchor customer would be the Kensington Mine, which runs on onsite diesel generators today.

Money has been the central hurdle. Duff Mitchell, Juneau Hydropower's managing director, estimated in October 2025 that the project would cost about $270 million and said he was pursuing a USDA Rural Utilities Service loan that could cover up to 75% of it. "So the fun part starts now, which is completing our financing," he told KTOO at the time.

When the Regulatory Commission of Alaska certified Juneau Hydropower as a utility in June 2025, it required proof of financing before construction and tied its approval to building the project before the federal license expires. "We are concerned about JHI's lack of loan approval," the commission wrote, KTOO reported. Alaska Electric Light & Power, Juneau's existing utility, has appealed the state approval in Alaska Superior Court. Nature World News did not confirm the current status of that appeal.

Salmon Habitat and Local Stakes

The project sits in salmon country. NOAA Fisheries lists sockeye and pink salmon as federal trust resources tied to the site and notes that the sockeye run, which supports a popular personal-use fishery, is stocked by the Alaska Department of Fish and Game. The dam would be built above a series of waterfalls that block natural salmon passage into the lake, according to Associated Press reporting on the project.

The licensed design includes fish screens at the intake, a fish exclusion structure on the tailrace, and a salmon smolt re-entry pool beside the powerhouse, according to the project description in the Rural Utilities Service notice. How well those measures perform will matter to anyone who fishes Gilbert Bay and the mouth of Sweetheart Creek.

For Juneau households, the effect would be indirect. Juneau Hydropower and AEL&P each have their own service territories, and serving customers inside AEL&P's territory would require the new utility to sell its power to AEL&P, according to KTOO.

Mitchell has argued the added capacity would strengthen energy security after a natural disaster, a point with local resonance. In 2008, an avalanche took out part of the Snettisham transmission line, which carries power from a state-owned hydroelectric plant that supplies about two-thirds of Juneau's electricity, and the resulting outage lasted about two months.

The groups with the most direct interest are the mine, which could sharply cut its diesel use; people who fish for salmon near Gilbert Bay; the federal and state resource agencies that set license conditions; and AEL&P and its ratepayers.

Deadlines and Unanswered Questions

The biggest unknowns are financial. The notice does not say whether the federal loan has been approved, and neither the company nor FERC has publicly explained, in documents Nature World News reviewed, what specifically delayed a 2026 groundbreaking. It is also unclear how quickly FERC will rule once comments close.

Anyone may file comments, protests, or motions to intervene through FERC's eFiling system, or submit brief comments of up to 6,000 characters through eComment, citing docket P-13563-003. Only those who file a motion to intervene become formal parties to the proceeding, and every filing must state its evidentiary basis.

The deadline is 5 p.m. Eastern Time on Oct. 1, which is 1 p.m. Alaska Daylight Time. FERC's Office of Public Participation can help first-time filers, and filings are searchable in the agency's eLibrary under the project number.

A hydropower plant licensed a decade ago is still waiting on financing, and a new law gives regulators a way to keep its path to construction open. The next checkpoint is the Oct. 1 comment deadline, followed by FERC's decision on whether the company has shown good cause for more time.

What Readers Want to Know

What is Juneau Hydropower asking FERC to do?

The company wants two more years to begin construction, moving the start deadline from Sept. 8, 2026, to Sept. 8, 2028, and two more years to finish, moving that deadline from Sept. 8, 2029, to Sept. 8, 2031.

Is this a new license application?

No. FERC licensed the Sweetheart Lake project in 2016. The current filing only asks for more time to start and complete construction.

What law allows the extension?

Public Law 119-90, signed May 11, 2026, lets FERC grant up to three additional two-year extensions for hydropower projects licensed before March 13, 2020, if the licensee shows good cause.

How can I comment?

File through FERC's eFiling or eComment system using docket P-13563-003 by 5 p.m. Eastern Time (1 p.m. Alaska Daylight Time) on Oct. 1, 2026.

Would the project lower electric bills in Juneau?

Not directly. Juneau's homes and businesses are served by Alaska Electric Light & Power, and power from the new project would reach that territory only through sales to AEL&P. Any household effect would depend on future agreements.

Could the dam affect salmon?

NOAA Fisheries lists sockeye and pink salmon as trust resources at the site. The dam is planned above waterfalls that block natural salmon passage, and the licensed design includes fish screens and a smolt re-entry pool.