Proposed Alaska dam pushes state to examine hydropower options

Corrected August 5, 2011, 2:53 p.m.

Mile 184 on the Susitna River halfway between Anchorage and Fairbanks may look a little different in 12 years.

Imagine a 700-foot high dam with a reservoir 39 miles long. That's what could be there if the proposed $4.5 billion Susitna-Watana hydroelectric project secures permits and financing. The project got a "pass go" from Alaska's Senate and the project's main proponent, Gov. Sean Parnell, in mid-July.

The largest proposed U.S. dam in decades, it would have a generation capacity of 600 megawatts, comparable to that of the Vermont Yankee nuclear power plant in Vernon, VT. In comparison, the Hoover Dam on the Colorado River on the Nevada-Arizona border stands 726 feet tall and generates 2,078 megawatts.

"It's time for Alaska to make the needed investment in renewables that we have in abundance, more than any state in this nation," Parnell said in a July news conference. The project would help meet the state's mandated energy target, which requires half its electricity need be met with renewable sources by 2025.

It’s a big jump for a state that was getting 53 percent of its electricity from natural gas as of 2009. Hydropower accounted for 19 percent, and other renewable resources for 0.2 percent.

What's more, the state has a history of choosing fossil fuels over renewable ones. In the 1980s, it spent $227 million to study dam sites on the same river, then abandoned the project when oil prices dropped and better natural gas prospects surfaced.

But the plan seems a little more feasible this time around — the 1980s projects were larger (about $5.4 billion in 1985 dollars).

Another pricey non-renewable energy project may tempt the state, though. The $7.5 billion Alaska Stand-Alone Pipeline project, an in-state, state-subsidized natural gas pipeline 317 miles south on the Susitna River in Cook Inlet 737 miles in lenght between Prudhoe Bay and the Cook Inlet area was proposed the same day of the dam’s approval, and its price tag could create problems if both projects go to the bond market for financing at the same time, said senator Lesil McGuire at an In-State Gas Caucus meeting. The pipeline plans were bolstered by To further shake up the mix on what gas is available in the state, the U.S. Geological Survey, announced in June results of a new survey of the inlet's tappable energy resources. That report revealed a much larger treasure trove of natural gas and oil reserves than had been previously estimated, thanks in part to better recovery technology.

Even more alluring is what the pipeline would do for ratepayers. The Daily News-Miner reported that it "could be expected to deliver natural gas to Fairbanks at less than one-half the current retail price here, according to the state-owned Alaska Gasline Development Corp.’s analysis last month."

Whatever happens with financing, Alaska Housing Finance Corporation's chief executive officer Dan Fauske says electricity demand will make both projects appropriate. "His analysis showed that both the big Susitna River hydroelectric project proposed by Gov. Sean Parnell and the in-state line would be needed," the Juneau Empire reported.

Interestingly, opponents of the dam concerned about environmental impacts appear to be pushing Alaska to stay reliant on fossil fuel. Richard Leo, a member of the newly formed Coalition for Susitna Dam Alternatives, questioned whether the dam was necessary when the natural gas reserves could already fill the state’s energy needs. He fears the dam will impact caribou habitat and salmon runs, becoming "destructive on a massive scale." Climate change may already be impacting the state, but that doesn’t mean it precious resources should be traded for their energy, he says.

"Massive dam projects have been shown internationally across the past 20 years to no longer be the most effective way to generate electricity…their potential destructiveness outweighs the amount of electricity they can create."

Kimberly Hirai is an intern at High Country News

Image of the Talkeetna-Susitna river confluence courtesy Flickr user Travis S.