Pebble Mine, as currently proposed, will draw 50 million standard cubic feet per day of natural gas through a 12-inch subsea and overland pipeline from the lower Kenai Peninsula to its site in southwest Alaska for power generation, Pebble spokesman Mike Heatwole told Petroleum News in a June 4 interview.
Heatwole said mine developer Pebble Partnership designed the pipeline and the powerplant to deliver more power than the proposed copper-gold-molybdenum-silver mine needs, in part to make power available to local residents.
“Both natural gas and electricity we would make available for the community should there be interest,” he said. “For the power of course, that would be at cost; I don’t know quite how it would be structured for the natural gas.”
The communities in the region near the mine site currently rely largely on fuel oil or gasoline - which must be barged or flown in – for power generation.
“We’ve long said that our view is, one of the big opportunities that comes with a project such as Pebble is the infrastructure that of course comes with it, and we use the example of the hydroelectric power facilities down in Juneau where the mines put them in and eventually turned them over to the city for their electrical power,” Heatwole said.
Pebble won’t, however, deliver gas or electric directly to consumers.
“Of course, we don’t want to be in the utility business, and local communities and other regional entities - probably the state - will have to work on how does that really come together,” Heatwole said. “We work on getting the infrastructure in there and have both gas and electricity available; how it goes from there of course is largely a local decision.”
270 megawatts capacity
Pebble plans a powerplant generating capacity of 270 megawatts to meet the projected power requirement while providing sufficient peaking capacity and redundancy, it said in a 2018 project description. One generating unit will be held in reserve for maintenance or emergency use. The plant will use high-efficiency combustion turbine generators operating in a combined-cycle configuration.
Gas-fired electrical generation eliminates the need to transport and store large amounts of diesel, Pebble said.
Waste heat from the power plant will be used to heat mine site buildings and to supply process heating to the water treatment plant, Pebble said. Low-pressure steam, through heat exchangers, will heat a closed loop glycol system to heat buildings, while warm water from the steam condenser discharge will be routed to the water treatment plant.
Construction of the gas line and the power facilities is expected to begin several years from now. Heatwole said the U.S. Army Corps of Engineers said it intends to publish the final environmental impact statement for the project near midsummer, followed by a record of decision 30 to 45 days later.
At that point Pebble will initiate plans for state permitting, process which could take two or three years, followed by the sanction decision on construction, he said.
Heatwole said Pebble did two days’ worth of drilling work in April to study soil conditions near its gas compressor site along the Sterling Highway north of Anchor Point on the Kenai Peninsula. The work will inform the route of the pipeline which will be bored under the bluff and beach, rising to the seafloor and extending 75 miles across Cook Inlet to Ursus Cove on the west side.
Heatwole said he was not aware of talks with specific producers about buying gas for the project.
“Obviously there’s a lot of talk about, ‘could projects such as Pebble and Donlin facilitate more interest in what else is in the Cook Inlet basin in terms of gas beyond just what the Southcentral consumers are using?’” he said, adding, “but we haven’t had those formal conversations.”
