Photo Courtesy Alaska Energy Authority
Field studies to support a FERC license application are continuing in Alaska.

Studies have resumed for the $5.6-billion Susitna-Watana Hydroelectric Project in Alaska, following clarification in July of an executive order by Gov. Bill Walker (D) limiting government spending. Plummeting oil prices prompted the order last December “to stop non-obligated spending” on six megaprojects, which have a total estimated cost close to $7 billion. The hydro project is the largest of that group.

Since the completion of the Trans-Alaska Oil Pipeline, petroleum revenues to the state have averaged over 85%, according to the Alaska Oil and Gas Association. No other state is so dependent on one industry to fund government services. The oil-price collapse thus dealt a substantial blow to the state’s ability to fund infrastructure megaprojects, necessitating a reassessment (ENR 3/30-4/6/15 p. 6).

The executive order “has allowed the state to limit the amount of spending on these six projects in order to determine the appropriate path forward for each,” says Katie Marquette, the governor’s press secretary. “The administration’s goal with Susitna-Watana is to get as much value as possible from the money that has been invested in the project thus far and then leave it at a pause point until the state’s financial situation changes.”

The proposed dam is designed as a curved gravity dam, with a straight gravity section on each abutment. It would contain 5.2 million cu yd of roller-compacted concrete. The crest, which is 2,810 ft long, would be 705 ft above the prepared rock foundation. Bedrock is diorite to quartz diorite. The impoundment would be 42 miles long and average 1.25 miles wide, comprising 3.4 million acre-ft of active reservoir storage. The 459 MW generated by its three turbines would be capable of meeting about half of Railbelt Alaska’s electrical demand, and plans include, if needed, an empty bay to add a fourth unit later, says Bryan Carey, engineering manager for the Alaska Energy Authority.

The project would be located 125 miles northeast of Anchorage and 140 miles south of Fairbanks, Carey says. “Nearly 80% of the state’s population live in the region that stretches from Fairbanks to Homer, referred to as the Railbelt.” Related construction would include a permanent access road to the dam site, likely with extensive span bridges, he says. “The main dam site would require a construction camp and permanent facilities, including an airstrip. There would also be a smaller construction camp at the Alaska Railroad off-loading location.”

MWH Global is the engineering consultant for the project and did the conceptual design, says Wayne Dyok, AEA senior project manager. He does not have an owner’s engineer but had been planning to issue a request for proposals for one when the price of oil was high. Now, he says, “We are not authorized to proceed with the engineering.” Currently, he is authorized to proceed only to “study plan determination” to obtain a Federal Energy Regulatory Commission license. He expects to reach that milestone this year.