Article by: Reed Karaim
Alaska is a land of majestic mountains, wide rivers and sweeping tundra. But when it comes to electricity, Alaska is the land of microgrids. The vast state’s rugged terrain and scattered population make a statewide grid impractical.
Microgrids are usually defined as stand-alone generation systems embedded within the larger grid. For most Alaska communities, however, there is no larger grid. They have to generate their own power, which means the state’s electric cooperatives have become real-world experts in managing microgrids.
Optimistic commentators, especially some renewable energy advocates, believe microgrids have the potential to relieve the U.S. of its dependence on large power plants. Fast Company magazine headlined one article “Why the Microgrid Could be the Answer to our Energy Crisis.” Robert Galvin and Kurt Yeager went even further with their book, “PERFECT POWER: How the Microgrid Revolution Will Unleash Cleaner, Greener, More Abundant Energy.”
But the managers of co-ops that actually operate self-contained systems have a more measured view of their potential, their costs and the challenge of integrating renewables. “The reality is these sort of microgrids are more complicated than many people assume,” says Brad Reeve, general manager of Kotzebue Electric Association, which operates a mix of wind and diesel generation in the village of Kotzebue, 33 miles north of the Arctic Circle.
“The reality is these sort of microgrids are more complicated than many people assume,” says Brad Reeve, general manager of Kotzebue Electric Association, which operates a mix of wind and diesel generation in the village of Kotzebue, 33 miles north of the Arctic Circle.
The cooperatives working with microgrids have taken innovative approaches to providing the reliability and quality their members count on, while also expanding their commitment to renewable energy. Kotzebue Electric hopes to get about 20 percent of its annual power from wind, but when it’s really blowing, wind can provide 100 percent of its load. Sudden shifts, however, can create excess capacity. To compensate, the co-op offloads power into thermal storage, heating boiler water in several buildings. The co-op is also installing a large battery, which arrived in September, to provide further options and reduce its diesel generation.
Maintaining reliable power in a small grid so dependent on renewables requires a sophisticated, custom-tailored SCADA system. “It took a lot of thought about how you make this work without creating grid stability issues or damage to people’s equipment. In large regard, what we’re doing here is still considered a demonstration project – so don’t try this at home,” Reeve jokes.
Several Alaska co-ops combine renewables with diesel. Kodiak Electric Association serves about 13,000 members in and around Kodiak with a mix of mostly hydro and some wind and diesel generation. Managing the various sources of power on a small system provides a continual challenge. The co-op has invested in batteries and flywheel storage, but still needs diesel generators to maintain reliable power. Darron Scott, Kodiak president and CEO, believes combining wind and hydro has the potential for wider application. “If you’re pumping water up the hill when the wind is high, then you can let the water run down the hill when the wind is low,” he says. “They can work well together.” Still, integrating it all in a microgrid takes sophisticated control systems and continual attention. “It’s very dynamic. The frequencies are just not as tight,” Scott notes. “It’s much more difficult to keep that 60 cycle power on a grid of this size.”
The co-op has invested in batteries and flywheel storage, but still needs diesel generators to maintain reliable power. Darron Scott, Kodiak president and CEO, believes combining wind and hydro has the potential for wider application.Battery storage is often discussed as a way for renewable-powered microgrids to compensate when less power is being generated. But when microgrids become a little less ‘micro’ the amount of battery storage required can be staggering. Golden Valley Electric Association serves nearly 100,000 residents in and around Fairbanks. The co-op gets about a third of its power over a 350-mile line connecting it to the Anchorage area – a connection Brian Newton, CEO and president, good naturedly refers to as “the world’s longest extension cord.” The line is fragile enough that the cooperative maintains sufficient generation to handle its load in the event of a disruption. Golden Valley also has what is believed to be the largest battery in the world. It weighs 1,300 tons, runs the length of a football field, is half again as wide, and thirty feet tall.
The battery system can provide 27 megawatts of power for 15 minutes, enough time for the co-op to fire up diesel generation when necessary. The cooperative is building a large wind farm that should provide about ten percent of its load. “In a weak grid that’s the most I can put on,” Newton says. Overall, he is skeptical about the idea of renewable-energy powered microgrids freeing the nation from large power plants. “You simply cannot power today’s home with these alternate fuel sources,” he says. “If you could, everybody would be doing it, and we would have switched from central generation.”
“You simply cannot power today’s home with these alternate fuel sources,” he says. “If you could, everybody would be doing it, and we would have switched from central generation.” The best example of the different hurdles that come with microgrids may be found at Alaska Village Electric Cooperative, based in Anchorage, which operates 49 separate generation plants to serve 53 small villages. Meera Kohler, Alaska Village president and CEO, says logistics – providing fuel, parts and maintenance over large distances – is the biggest challenge. “You can’t afford to have a lineman or a skilled mechanic at each location,” she notes.
Microgrid advocates may see smaller as better, but Alaska Village is building up the size of its grids. “One of our priorities is to interconnect villages because there’s so many benefits to be had. You can cut costs and increase reliability,” says Kohler. “By covering more geography, you’ve also got more exposure to better wind regimes you can tap into.” Overall, she notes, it’s easier to integrate renewables into a larger grid than a smaller one because the system is less vulnerable to the unevenness of renewable power.
Co-ops in other parts of the country illustrate this. Kit Carson Electric Cooperative, based in Taos, New Mexico, has several solar arrays on its system that power microgrids during the day. These include a 500-kilowatt facility for a community college campus and a 1.25-megawatt array that provides electricity to Questa, a village of about 1,000 residents. Louis Reyes, Jr., Kit Carson CEO, believes these type of microgrids make the most sense for “places at the end of the line. . . . It can really help stabilize the power in these areas,” he says, while also lessening dependence on fossil fuels.
But Reyes notes that when the sun goes down Questa and other locations powered by solar are back on the grid. Base load provided by coal-fired power plants remain essential to providing members in those areas the reliable electricity they count on. “You need that mix,” he says. “It’s not just one technology or approach that’s going to carry us forward to be a successful energy country.”