Alaska proposes large new dam

The Alaska Energy Authority has filed key documents with federal regulators giving formal notice of its intent to build the proposed 600 megawatt Susitna-Watana Hydroelectric Project.  If this project is approved and built, it will be the largest hydroelectric project developed in the U.S. since 1966.

Plans to develop a large-scale hydropower project on the Susitna river have been considered for decades.  In 2010, the Alaska Legislature established a goal of providing half of the state’s electric power from renewable sources by 2025.  The Alaska Energy Authority, a public corporation of the state whose mission is to use Alaska's natural resources to produce electricity and lower costs, concluded that Alaska could not meet the 50% renewable goal without building a major new hydroelectric project.

On December 29, 2011, the Alaska Energy Authority filed a notification of intent to file an application for a hydroelectric license and a pre-application document with the Federal Energy Regulatory Commission.  FERC docketed the project as No. 14241.  (You can read these documents in FERC's eLibrary here.)

In those documents, the Alaska Energy Authority described the project as located about 180 miles north of Anchorage.  The dam itself would be large: 700 to 800 feet in height, and with a crest length of over 2,700 feet.  The dam would impound a 39-mile-long reservoir, flooding 20,000 acres and capable of storing about 2,400,000 acre-feet.  The Authority plans to install three 200 MW turbine-generator sets for a total installed capacity of 600 MW, but is considering up to 800 MW of capacity.

The Authority expects the FERC hydropower licensing process to take up to 6 years.  The size and impacts of the project make it attractive to some yet controversial to others.  Public comments are already being filed in the FERC docket.