Ameresco Partners With Alaska Utility on Juneau Hydropower Project

Energy solutions provider Ameresco announced a partnership with Alaska’s Juneau Hydropower to develop, build, and operate a 19.8-MW hydropower station at Sweetheart Lake. The facility is located 33 miles south of downtown Juneau. The project also includes installation of a battery energy storage system (BESS) and more than 40 miles of high-voltage transmission infrastructure.

Officials said the Sweetheart Lake station is designed to generate an average of 116,000 MWh annually. The companies said the new plant will bring a 20% increase in baseload clean hydropower above Juneau’s current power generation. The project scope also includes eight miles of undersea cable that will cross Gilbert Bay, and an interconnection substation with the existing Snettisham transmission line serving Alaska’s capital city.

Juneau Hydropower secured the first permit for the hydropower station in 2016, which the utility said came after seven years of research, planning, and design work for the project. Juneau Hydropower on Tuesday said it is developing power generation infrastructure to connect underserved, remote areas that previously have relied solely on burning diesel fuel to generate power.

The utility also said it is working to enhance power reliability and resilience in a region that often experiences extreme weather. The group noted that a 2008 avalanche resulted in power outages that in some instances lasted as long as two months.

Sweetheart Lake, along with increasing the power supply for the Juneau area, also is expected to increase the overall transmission of electricity across Alaska by 3%.

Catalyst for Growth

“This project is the catalyst for Juneau’s sustained growth and prosperity, and we’ve used over 40 years of hydrological data to design hydropower operational parameters so that we can reliably produce energy in even the driest of years,” said Duff Mitchell, managing director for Juneau Hydropower. “By harnessing the power of Alaska’s waters, we’re investing in a future where unprecedented events can be weathered with confidence. We’ve worked in harmony with local environmental scientists and stakeholders to create the reliable, resilient power needed by our community.”

Sweetheart Lake is located within the territorial limits of the City and Borough of Juneau, Alaska on the east shore of Gilbert Bay. The lake drains into Gilbert Bay, which is part of Port Snettisham, via Sweetheart Creek. Officials said the hydroelectric dam is expected to offset 82,012 metric tons of CO₂ emissions annually.

Among the groups that will receive power from the hydro station is Coeur Alaska’s Kensington Mine, located 45 miles north-northwest of Juneau in the Tongass National Forest. The mine is currently powered by onsite diesel generators, but is expected to transition to primarily renewable baseload energy to power operations once the Sweetheart Lake station comes online.

“This multi-faceted project is a major milestone for both Alaska, Juneau Power and Ameresco,” said Nicole Bulgarino, president of Federal Solutions and Utility Infrastructure at Ameresco. “We’re proud to be working on this critical hydropower project and major electrical infrastructure that has factored in both community needs and responsible development, in addition to supporting energy reliability and long-term economic growth in line with the vision outlined in the ‘Alaska Executive Order: Unleashing Alaska’s Extraordinary Resource Potential’.”

A long-term operations and maintenance also is part of the contract for the project.

—Darrell Proctor is a senior editor for POWER.