Southcentral’s rainy summer means more hydroelectric power for Homer Electric Association and other utilities on Alaska’s Railbelt. Last month, the water level at Bradley Lake was just five feet away from spiling over the top of the dam — letting utilities take more energy from the 120-megawatt hydroelectric project and cut back on using more expensive fuel sources, like natural gas.
Bradley Lake, across Kachemak Bay, generates energy for six utilities across the Railbelt. HEA gets about 14% of its power from Bradley today; the remainder comes from Cook Inlet natural gas.
And the impacts of rain on the water levels at Bradley Lake are two-fold.
First, the rain itself means higher water levels on the lake.
But the rain also quickens the melting of snow and glaciers, sending more water down to the lake.
“When the lake hits this certain elevation, it is literally quite close to the top of the dam,” said HEA Board Member Erin McKittrick, of Seldovia.
She said there are certain rules built in to make sure that water isn’t wasted by spilling over the dam. The project reaches what’s called “imminent spill” when the water level hits 1,175 feet, as it did last month. (The real spill level is 1,180 feet.)
As it stands, HEA is sometimes the biggest beneficiary of that extra water because of its proximity to the resource. But all the utilities are able to take more water power and, in turn, turn back the dial on how much natural gas they use to electrify their grids.
Power from Bradley Lake is cheaper than that gas, at 4 cents per kilowatt hour. And in rainy years, like this one, that power is even cheaper.
“The costs that they’re incurring right now at Bradley are not higher because it rained more,” McKittrick said. “They’re about the same as they would be any September. But there’s more water, so more water gets generated. So all that power is cheaper.”
As for rates, HEA Director of Strategic Services David Thomas said the changes do make a difference — albeit, a small one.
HEA base rates remain the same for a year or more at a time. But the utility’s so-called Cost of Power Adjustment changes every quarter and reflects the co-op’s use of fuel. When there’s more hydropower, that adjustment can change by one or two tenths of a cent.
According to a report from the Alaska Energy Authority, Bradley Lake has only had levels this high this soon in the summer twice before — once in 2003-2004 and again in 2014-2015.
