Alaska Center of Energy and Power's Arctic Solutions: integrating traditional and alternative energy into power grids.

• Author: Stricker, Julie
• Position: ENERGY

In spring 2013, a stubborn ice jam on the Yukon River sent floodwaters surging into the small community of Galena, virtually wiping out the village.

About half the homes in Galena, population 470, were deemed uninhabitable. Roads and power lines were washed out, the diesel power station was damaged, and residents lost freezers full of subsistence foods such as meat and berries, which spoiled after days without power.

Galena's power grid is typical of those throughout much of rural Alaska. The village is not on any road system--the only access is by plane, boat, or snowmobile. Its grid is also small and isolated.

In rebuilding, Galena residents decided to make a big push toward using solar power, but mixing traditional power generation with renewable power solutions can cause problems if it's not managed correctly. That's where the Alaska Center for Energy and Power's (ACEP) Power Systems Integration program came in.

Dual System Power Grid

Marc Mueller-Stoffels, a research assistant professor at the University of Alaska Fairbanks and the program director for Power Systems Integration, worked with Galena officials to help design an efficient dual-system power grid.

"The city was pretty gung-ho," Mueller-Stoffels says, noting the city already had about 30 kilowatts of solar panels installed. "The problem was when you add a lot of renewable power into these small micro-grids, the variability in these resources really drives the diesel very hard. If that's not managed well, you might have poor power quality or you might damage your diesel."

Mueller-Stoffels says one problem was that the power station had lost its automation, and workers had to keep turning the diesel on and off by hand. They had no communication between the power station and the photovoltaic cells, which don't turn off automatically when they reach critical levels.

"If you don't have control over your solar array, the diesels have to be able to buffer the changes," he says. "Solar can lose 80 percent of its power input if, say, a cloud rolls over it. At that point, the diesel has to ramp up."

At the same time, a village doesn't want to run a diesel engine that's too big for its needs. Mueller-Stoffel says he ran some equations based on the community's energy needs and current output.

"I made some recommendations gauging how much PV they could add to the grid," Mueller-Stoffels says. "In the case of Galena, that comes out to about 130 kilowatts total."

His report also noted that the power grid overall was fairly weak and included recommendations on what...