Warming may help Southeast produce power

Posted: Thursday, December 09, 2010

Climate change may be causing problems elsewhere, but it may provide some big benefits to Southeast Alaska, according to a new study looking at the region's hydroelectric potential.

Warmer winters and more precipitation are likely to combine to make Southeast's hydro dams more productive, according to a University of Alaska Fairbanks study.

"Since rain is our fuel, it means we can get more energy out of our hydro projects," said Scott Willis, generation engineer with Alaska Electric Light & Power, Juneau's power provider.

Sitka Electric, the municipal utility for the island city, commissioned the study but looked at water data for all of Southeast and is being studied by engineers throughout the region.

Despite the region's sometimes sketchy precipitation data, especially crucial snowfall information at higher elevations, the report's authors said the local warming is likely to mean more precipitation as well.

"Like much of Alaska and the Far North, Southeast Alaska is projected to warm considerably by the end of the century, with much of the warming concentrated in the winter," according the Impacts of Climate Change and Variability on Hydropower in Southeast Alaska: Planning for a Robust Energy Future.

The report predicted wintertime temperature changes with different models available, and found all showed warming from 3 to 6 degrees Celsius, or about 5 to 10 degrees Fahrenheit

"All five models are consistent in the result, with differences only in the rate of warming," the report said.

If that additional precipitation comes at the right time, and can be captured for electric generation, more water could be good for Southeast's utilities, said Chris Brewton, superintendent of Sitka Electric.

Sitka commissioned the study because it is in the midst of trying to raise its Blue Lake Dam to meet the city's power demand, but needs to know how much water it should expect.

Each community is likely to be affected differently.

In Juneau, more winter precipitation is likely to be good news, Willis said. If it comes in the fall, when the city's reservoirs are typically full, it won't be of much use.

"If all we get is more fall rains, we just wind up spilling more," Willis said.

Higher winter temperatures, if they mean more water entering the reservoirs when it is most needed, would appear to give Juneau more power, he said.

"I think warmer winters will be good for the hydro project -- we'll be able to completely fill the reservoir," Willis said.

More precipitation throughout Southeast is likely to mean more power can be produced, but the report also warned of more variability and drought years as weather fluctuations such as El Nino and La Nina events many mean occasional unusually dry years as well.

Brewton and Willis said the report shows the need for more electric interties between cities, allowing those with surplus power to help out those going through dry years, without going to expensive backup diesel generation.

Juneau is unusual in Southeast in that it can sell extra power beyond what is needed by residents. It has what are known as "interruptible" customers in the Greens Creek Mine on Admiralty Island, or with cruise ships docking downtown.

"It's nice to have that mine load and I'd like to see them on as much as possible, but I don't want to run short for my other customers," Willis said.

With the completion of Lake Dorothy last year, AEL&P should be able to provide all the power needed by the mine and cruise ships, though they might have to be cut off in particularly dry years, he said.

Better interties between the region's energy producers and consumers would be costly, but would guarantee more stable power prices and availability, Willis and Brewton said.

"It's going to take some investment," Brewton said. "We're going to have to spend some serious money to get it done."

The UAF report recommended more precipitation monitoring so utilities know what is available, and to be able to better plan for customer demand and new projects.

Willis said AEL&P is paying for a Natural Resource Conservation Service weather station in the Long Lake Basin that provides useful data for both scientists and the utility. The report said more such stations are needed around Southeast, and that significant gaps in current and historic data make it difficult to plan for new hydroelectric projects.

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