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The rural electric cooperatives are testing how the storage technology can help customers and their systems.
Four Midwestern rural electric cooperatives are installing smart batteries in the homes of a few customers to test whether they can economically reduce peak demand or provide other benefits to customers or their systems.
The co-ops came together through a professional association and pooled their purchasing power to buy the batteries, which have built-in management systems that allow them to, for example, monitor energy use.
The MiEnergy Cooperative, which serves northeastern Iowa and southeastern Minnesota, recently installed the batteries in six customer homes. Two of the homes have solar panels; a third has a backup generator.
The other co-ops are Richland Electric Cooperative and Oakdale Electric Cooperative in Wisconsin, and Jo-Carroll Energy in Illinois. Together, they plan to experiment with different approaches to charging and discharging the batteries.
“We want to discover the pros and cons with regard to battery storage, and how it might affect our members,” said Pat Boyle, MiEnergy’s marketing and member services representative. “I don’t know if it’s going to be cost effective” to use batteries to shave peak demand.
Batteries have potential to cut the cost of power if they can sufficiently reduce electricity use during peak hours, which for MiEnergy usually falls between 10 a.m. and 5 p.m. The batteries monitor energy use throughout the day and night at each household and are being programmed to charge from the grid when demand for power is low and discharge when it peaks.
“At night we have power plants that are idling,” Boyle said. “If we could keep plants running steady all the time, it helps control costs. If we can spread out the load, we don’t need the same capacity.”
The Iowa Economic Development Authority, which wants to push ahead on energy storage, gave MiEnergy $87,000 to support analysis of data generated by the batteries.
“We want something that’s going to be able to inform many projects coming behind it, so they can walk more carefully,” said Brian Selinger, who directs the authority’s energy program. “We figure there’s much to glean.”
The authority also has provided funds to support battery experiments at a university and a manufacturer in Fairfield, Iowa, each of which has solar arrays and batteries.
“We need to understand what are the benefits of the various energy storage technologies, whether they are utility-scale or residential,” Slinger said. “And what works in the Iowa climate?”
The Richland Electric Cooperative in Richland Center, Wisconsin, has similar questions about storage and its potential to complement its system.
“There are so many variables we want to look at,” said Shannon Clark, Richland’s general manager and chief executive officer. “What impact can it have on power quality, demand response, load management? Does a battery without distributed generation provide value? It may. If you charge it during off-peak hours, does it enable more solar or intermittent resources by moving a household to a battery?”
Clark has purchased a couple of batteries that will serve as the basis for his experiment. One will be installed in the home of a customer with solar panels; the other will go in a co-op learning center that is open to the public.
Clark thinks batteries could significantly enhance his co-op’s operations — or not.
“There’s a lot of anecdotal evidence that batteries are good for smoothing out how we use energy. But when it comes to actual installation, we’ve heard you lose 14% of what you generate by putting it into a battery and taking it back out. Maybe that’s such a penalty you’d be better off without the battery.”
“If the discount is 15% for [purchasing] power off-peak, and you lose 14% when you put it on a battery, that doesn’t do much good.”
But then again, the wholesale market for power can be volatile, he pointed out, and buying power on short notice on a hot summer afternoon can be a pricey proposition. “Batteries might help us mitigate that,” he said.
Clark said he expects to evaluate his experiments after he’s collected a year’s worth of data. Boyle will need to report to the state’s economic development after he’s run his pilot for 12 months, but said he may continue to collect data for a few more years.
The four co-ops, which worked as a team in purchasing the batteries and training their employees on how to operate them, also likely will collaborate in analyzing the results of the experiment.
“We’re good at not duplicating each other’s work,” Clark said.
Although he thinks the pilots could answer any number of questions, Clark said his foremost interest is in determining whether solar panels are more potent when paired with a battery, or should stand alone to be used with net metering.
“That’s a lot of capital,” he said. “What’s going to be the return?”
At MiEnergy, Boyle said the results of the pilot probably will help in deciding whether to offer a time-of-use rate which is higher during peak times.
The home battery experiment offers “boundless possibilities” as Clark sees it. “We just have to determine how many have overwhelming challenges.”