In 2011, the State of Alaska resurrected previously discarded plans to dam the Susitna River—the first dam of its type or size to be proposed in the United States in more than 40 years. Here’s what you need to know:
The Susitna Dam, if built, would become the 2nd tallest dam in the United States and would pose significant harmful impacts to the Susitna River’s five species of salmon, caribou migration routes, and tourism- and fish-based businesses. The massive structure would be taller than the Hoover Dam and three times taller than any other dam in Alaska. In an era when dams across the country are being removed, building a new dam of this size and scale is questionable both from an economic and ecological standpoint.
The Susitna River, where the dam is proposed, is America’s 15th largest river by volume and drains an area nearly the size of West Virginia. The vast valleys that feed the Susitna River comprise some of the states most visited areas. It is the heart of Southcentral Alaska: massive mountains, deep forests, open tundra, and small communities with river-based economies. The river flows from mountain glaciers, unimpeded for 300 miles, through some the Alaska’s most rugged and wild landscapes to meet the Pacific Ocean near Anchorage where it is a significant contributor to Cook Inlet’s wild salmon fisheries.
What kind of dam are we talking about and where is it being proposed?
Size: The massive structure would be 735 feet tall, higher than the Hoover Dam and three times taller than any other dam in Alaska.
Type: This dam would span the width of the river, blocking upstream passage entirely. It would be “load-following,” meaning water is released to meet energy demands, which would create seasonal flows opposite of how the river normally flows.
Location: 87 river miles north of Talkeetna in the heart of one of the most visited, fished, and hunted areas of the state, one rich with salmon, moose, caribou, and bears.
Is the dam a smart investment for Alaskans?
The estimated price tag to construct the dam is between $5 – $8 billion. Because this is a state project, the public and the rate payers would foot the bill.
This is expensive power when compared to other large hydro projects. In adjusted dollars, Montana’s 600-megawatt Libby Dam cost only $1 billion and Grand Coulee Dam in Washington State cost the same as the proposed Susitna dam but produces 10 times more electricity.
State funds would also be required to acquire land, upgrade transmission lines, and mitigate damages to Susitna salmon fisheries. Hydropower mitigation costs billions of dollars on the Columbia River where they are desperately trying to save their endangered salmon runs.
How would the dam impact fish, wildlife, and local economies?
Load-following dam operations—like that proposed for the Susitna dam—severely alter the natural flow of river systems by dramatically reducing summer flows and increasing winter flows.
Altered river flows degrade or destroy sensitive salmon spawning and rearing habitat and important migration pathways which can severely impact the wild salmon populations the Susitna currently supports.
The proposed Susitna dam would create a 42-mile long reservoir that would flood 40,000 acres of prime bear, caribou and moose habitat—impacting one of Alaska’s most valued hunting regions.
Manipulated river flows and impacts to fish and wildlife resources threaten tourism and recreation businesses that are the cornerstone of the local economy, bringing in more than $200 million annually, and supporting more than 5,400 Alaskan jobs.
Is the proposed Susitna dam the only energy option for powering Railbelt Alaska? Does it compete with public funds to build the natural gas pipeline?
Not only is the state heavily investing in developing natural gas resources, money spent on the dam is in direct competition with the financing needed to move Alaska’s natural gasline forward – both projects tap into general funding from the state.
Furthermore, electricity is only 20% of the region’s energy use; Railbelt residents use 80% of their total energy to heat their homes. The dam would not solve the most pressing energy need: affordable heat. Alaska’s abundant supply of natural gas would provide both heat and electricity
Since the state resurrected the dam project in 2011, four Railbelt utilities have added new power plants totaling 440 megawatts of capacity, at a cost of roughly $800 million. The dam would realize just 300 megawatts average annual capacity, at a cost of over $5 billion. With all this newly added generation, there is no need for this very expensive dam in a region with so little demand.
In the near term, upgrading transmission lines along the Railbelt will promote efficiency and bring communities additional power that is currently wasted.
Investment in Alaska’s untapped renewable energy potential such as small-scale hydro, wind, geothermal and tidal power can provide stable energy throughout Alaska for future generations.
Alaska’s weatherization and energy efficiency programs also provide a strong return on investment for communities across the state.