Flow battery scrutinized at UAF
By ROBINSON DUFFY, Fairbanks Daily News-Miner
Published: August 12, 2006
Last Modified: August 12, 2006 at 03:48 AM
FAIRBANKS, Alaska (AP) - Normally when someone gets a new toy, especially an expensive electronic gadget, they take very good care of it. But not Tom Johnson at the University of Alaska Fairbanks Energy Center.
"We're going to try to kill it," Johnson said with a devilish smile.
He was talking about the Energy Center's newest toy, an experimental battery that could make alternative power, like wind or solar power, more cost-effective in rural Alaska.
On Aug. 2, Johnson and his colleagues installed the new battery, known as a flow battery, in their lab on the UAF campus. The device, developed by VRB Power Systems Inc., of Vancouver, British Columbia, is about the size of three large refrigerators standing side by side. It hummed softly as its energy cells were charging up.
The flow battery uses two large tanks of liquid electrolytes, a solution composed mostly of sulfuric acid to store energy. As the two solutions are continually pumped through the battery's innards, one takes on a positive charge while the other is negative. It's this play of opposing charges that allows the battery to output the energy it has stored.
It's the liquid storage medium that sets the flow battery apart from more traditional batteries, which usually rely on lead plates in acid to store energy, said Dennis Whitmer, the center's laboratory director. The acid eventually corrodes the lead, shorting out the battery.
"You can trash a lead acid battery in a day or two if you really work at it, by repeating deep-discharge cycles," Whitmer said.
That shouldn't be a problem in the flow battery, since the energy is all stored in liquids.
"This means there are no active solid surfaces to degrade," he said.
In theory, that means the battery could have an almost limitless energy-storing life span.
The team at the Energy Center will spend the next several years running the device through a battery of tests, evaluating its performance, durability and reliability. The first year or so will be spent in the climate-controlled lab.
"Once it survives the lab, we'll put it through some real-world abuse," Johnson said. They'll take the battery outside to see how it handles Alaska's extreme temperatures.
Since the electrolyte solution is mostly sulfuric acid, it shouldn't freeze until it gets really cold, Johnson said, but that doesn't mean the rest of the battery's components will be able to handle a deep freeze. The team needs to find that out.
"It's really important that somebody take a look at this and make sure it really works," Whitmer said. "I think of it less in terms of research and more in terms of service to the state."
A service to the state because the battery could help small villages in rural Alaska use wind or solar power instead of diesel fuel. Sources for alternative energy aren't always reliable. Batteries are used in alternative power systems to store excess energy when it's available to be used later. This eliminates the power outages that plague alternative power systems.
But Whitmer said conventional batteries can end up being more expensive than burning fuel because their short life spans eat up costs. If this battery really has the lasting power the manufacture claims, it could finally make alternative power sources economical for villages.
"There are many Alaskan communities that could benefit from this, especially with diesel fuel prices at $5 a gallon or more in some villages," Whitmer said.
UAF's Energy Center has been testing alternative energy systems for about eight years. The staff has experimented with fuel cells, converting diesel fuel to hydrogen, making synthetic diesel and utilizing fish oil as a fuel source. Johnson said outside interest in the center's work has increased in recent years.
"People are paying attention with gas at $3 a gallon," he said.
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Information from: Fairbanks Daily News-Miner, newsminer.com
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