FRAMINGHAM, Mass.– Ameresco, Inc. and Juneau Hydropower, Inc. have announced the launch of a $240 million hydroelectric project aimed at delivering renewable, reliable energy to Juneau and nearby remote communities. The project is one of the most significant infrastructure investments in Southeast Alaska’s energy landscape in decades.
Located at Sweetheart Lake, 33 miles south of downtown Juneau, the planned 19.8 megawatt (MW) hydroelectric facility is expected to boost the region’s baseload renewable energy by 20%. It will generate an average of 116,000 megawatt-hours annually and reduce carbon emissions by over 82,000 metric tons per year, according to project estimates.
The initiative also includes a large-scale battery energy storage system (BESS), over 40 miles of high-voltage transmission infrastructure—including eight miles of undersea cable beneath Gilbert Bay—and a substation that will connect to the existing Snettisham transmission line. Once completed, the system will help power parts of Southeast Alaska that have long relied on diesel generators.
“This project is more than power—it’s resilience,” said Duff Mitchell, Managing Director of Juneau Hydropower. “By using decades of hydrological data, we’ve designed a system that can operate even during dry years and withstand the kinds of weather events that have historically disrupted energy service in Juneau.”
Extreme weather has posed serious risks to Juneau’s grid in the past. A 2008 avalanche, for example, knocked out transmission lines and led to power outages lasting up to two months. The new infrastructure is intended to prevent similar disruptions by strengthening energy delivery systems and diversifying sources.
One of the first customers expected to benefit is Coeur Alaska’s Kensington gold mine, which is currently dependent on diesel power. The mine plans to switch to primarily hydropower once the Sweetheart Lake facility is operational, reducing its environmental impact.
The facility will also incorporate environmental protections. Developers say the project avoids fossil fuel combustion and supports local ecosystems, including fish habitats within Sweetheart Lake.
“This is a landmark project for Ameresco and Alaska,” said Nicole Bulgarino, President of Federal Solutions and Utility Infrastructure at Ameresco. “It aligns with Alaska’s broader goal to unlock its renewable resource potential while creating energy independence and economic opportunity.”
Ameresco and Juneau Hydropower will not only build but also operate and maintain the facility long-term, ensuring its continued performance and integration into Alaska’s energy infrastructure. The project is expected to increase energy transmission capacity in the state by 3%.
