Southeast Alaska is blessed with abundant water and steep terrain, resulting in a huge hydro power resource. The total theoretical hydro potential of SE Alaska is probably in excess of 10,000MW of capacity, with only about 200MW of this potential already tapped. Much of this potential will not be developed due to environmental concerns, or is located in protected wilderness areas or national parks. However, hundreds of remaining hydro power sites (mostly small-scale) could be developed with minimal environmental impact. Most of the region’s existing and proposed hydroelectric sites are lake-tap developments, on relatively small drainage basins with heavy runoffs. These lakes, typically formed by glaciers which receded after the last ice age, are perched at higher elevations, with tunnels or penstocks leading to powerhouses at lower elevations. Lake-tap projects often do not require a dam, and thus tend to have relatively low environmental impacts.
Regional hydro power resource assessment studies in SE Alaska date back to the 1920s, with the first report being “Water Powers of Southeastern Alaska” (US Forest Service, 1924). In the 1940s, the comprehensive study Water Powers Southeast Alaska (Federal Power Commission and US Forest Service, 1947) evaluated over 200 potential hydro power sites in SE Alaska, and also discussed a regional transmission system to interconnect hydroelectric plants and communities. The last regional study specific to small-scale hydro resources were commissioned by the US Army Corps of Engineers (CH2M Hill, 1979). This 1979 study was a reconnaissance-level analysis of mostly small (less than 10MW) run-of-river sites near twenty small communities in SE Alaska. A more up-to-date region-wide small hydro resource assessment is needed.
SE Alaska’s largest hydroelectric plant is the 78MW lake-tap Snettisham facility near Juneau. In addition, the region has sixteen existing hydroelectric plants in the small (1MW-50MW) category, six mini hydro plants (100kW-1MW), and at least ten micro hydro (less than 100kW) installations.
Source: Water Power Magazine. Brian Yanity 2009;
Juneau’s Hydropower and Grid system.
Juneau’s electrical grid extends from the end of Thane Road at its southern boundary to end of North Douglas road to the Hecla Greens Creek Mine on its western boundary. High power transmission lines extend to Lena Cove where a smaller transmission line further extends to the Eagle Beach area on the northern boundary of the Juneau Grid system.
On December 5, 2012, the City and Borough Assembly passed Resolution 2632: A Resolution Expressing Assembly Support for the Extension of Electrical Power along the Veterans Memorial Highway. This extension would provide electrical transmission and service to the northern public and private lands of the City and Borough of Juneau.