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By Ann Thelen

Most of us use batteries in some form to help power our lives every day. In simple terms, a battery converts stored chemical energy into electrical energy. From flashlights and toys to cellphones and vehicles, batteries have become a necessary part of our world.

While batteries have been around for centuries, advances in battery storage technology are sparking new ideas on how to power homes, electric substations or entire power grids more efficiently. Modern batteries can store excess energy produced by generators when demand is low, then seamlessly export the stored power during times of peak demand or weather-related power disruptions.

While the efficiency, cost-effectiveness and consumer applicability of battery storage solutions have a way to go for significant deployment, Iowa’s electric cooperatives are studying more about the ongoing advances in storage technology. 

Iowa co-ops explore potential battery storage solutions

From assessing residential batteries to coordinating large-scale substation battery storage, electric cooperatives across Iowa are exploring various innovative battery storage technologies. Many projects deepen understanding of electric storage technology and how it can benefit member-consumers.

“It’s an opportunity to embrace the future,” says Brian Krambeer, president and CEO of MiEnergy Cooperative. “We need to be educated about batteries and ready to provide this information and research to our member-consumers.”

With ongoing research, development and investment, battery storage technology can innovatively deliver safe, reliable, affordable and environmentally responsible energy. Today’s investment in model and scale-up projects has the potential to serve cooperative member-consumers far into the future.

Studying residential battery storage

MiEnergy Cooperative, which serves 18,000 members in northeast Iowa and southeastern Minnesota, launched a trial residential battery storage program in November 2018. In partnership with the National Rural Electric Cooperative Association (NRECA), the 5-to-10-year study is designed to gain insight into residential battery technology opportunities and limitations. 

“We chose to study residential batteries because we have 700 members that have installed distributed generation at their homes and farms,” Krambeer says. “It’s given us the momentum we needed to make sure we’re educated on the next round of technology our members may be considering.”

The study included residential sites across four participating cooperatives, including six MiEnergy Cooperative member-consumers. It was funded in part by a grant from the Iowa Economic Development Authority. The team at MiEnergy reports the following high-level findings:

  • The batteries (16kWh and 10kWh) worked seamlessly as advertised but were cost-prohibitive to the average user at the time ($19,672 to $14,522 plus installation costs).
  • Units cover about 20% of a home’s energy use and can fluctuate depending on the owner’s power use, varying from 263 to 1,030 kWh per month.
  • There is about a 30% efficiency loss, potentially due to daily storage loss and the inverter conversion from AC to DC.

There are limiting factors for residential applications. Homes need an internet connection, a conditioned storage space with temperatures ranging from 41 to 113 degrees F, and adequate ventilation and spacing for the unit.

“With the numbers, we are looking at a payback in about 35 years,” Krambeer says. “I don’t think anyone is running out right now for that kind of payback, but this is a test – it’s education and an investment for the future, especially as battery costs come down.”

This is an example of how MiEnergy is proactively looking for new opportunities to control costs, enhance service and exceed member expectations. In part because of this program, the cooperative was awarded a 2021 Electric Cooperative Purpose Award at NRECA’s PowerXchange conference.

Coordinating resources for substation battery storage

Northwest Iowa Power Cooperative (NIPCO), which supplies wholesale electric power to seven distribution cooperatives in western Iowa, recently completed a battery storage project at one of its substations.

The project was made possible in part through a Trial Battery Rate offered by Basin Electric Power Cooperative, the generation and transmission cooperative that provides power to NIPCO. The rate allocated up to 150 kWh per Basin Electric member cooperative, and NIPCO engineers developed a plan to pool and optimize this allocation across its membership.

“This approach was a perfect example of better serving member-consumers through the co-op principle of cooperation among cooperatives. Our coordination with Basin Electric and member cooperatives made this project possible,” says Matt Washburn, executive vice president and general manager of NIPCO.

NIPCO integrated a 950 kWh Tesla Mega Pack battery storage unit at its Lawton substation in December 2021. Stored power from the battery will replace almost 1 MW of power (enough to power 100 homes) for up to six hours during scheduled load control cycles. While this is only 1% of NIPCO’s total energy load, it’s an opportunity to study how the technology could be further incorporated while maintaining a reliable, economical power supply for member-consumers.

“We see this as a research and development project,” Washburn  says. “We want to see firsthand how batteries work operationally and financially.”

NIPCO plans to share ongoing performance data with its membership to highlight the battery’s ability to flatten demand curves, reduce power costs and use existing generating resources more efficiently.


How battery storage works

Battery storage systems recharge during off-peak times when energy use and power rates are lower. They can then discharge to provide on-demand energy for emergency power or during peak demand times, helping in the long-term to manage energy usage and lower member-consumer rates.

Three ways you benefit from battery storage

1. Cost savings

Power can cost more for electric cooperatives to purchase during peak times of energy use (such as summer months or dinner time when appliances are running). Batteries can help reduce this peak demand by discharging stored energy to help power the electric grid. Then, when energy costs are lower (like the middle of the night), batteries can recharge and store lower-cost power. Load management, or managing peak energy costs, is one of the best ways cooperatives can save member-consumers money.

2. Extra reliability

If a large power outage occurs on a transmission line, stored battery energy can kick on to power homes or businesses while the issue is repaired.

3. Preparing for the future

With the uncertainty of extreme weather events and changing state and federal energy policies, battery energy storage can help reduce some uncertainty. As battery storage technology evolves, it can potentially help take the unpredictability out of intermittent wind or solar energy generation, improve grid resiliency and reduce energy consumption. 


Ann Thelen is the editor of Iowa Electric Cooperative Living.

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