By Amanda Durish Cook

INDIANAPOLIS — Energy storage systems will inevitably take hold in MISO as costs decline, but the outlook for technologies outside lithium-ion batteries is less certain, storage experts told stakeholders Wednesday.

The experts were speaking on a panel convened by MISO’s Advisory Committee in lieu of the usual “hot topic” discussion where members sound off on current issues during committee meetings. The AC was unusually quiet during the event, instead electing to hear the panel of outsiders talk battery storage.

“Today we’re focusing on batteries. What are they going to look like in 10 years? What are the limits? When do they become commercially viable at scale?” moderator and MISO Vice President of Strategy and Business Development Wayne Schug said in opening the panel.

“Storage becomes very valuable when incremental capacity is scarce and expensive,” Brattle Group Principal Judy Chang said. She said she expected batteries to become cost-competitive when they serve capacity at peak times.

“I would say that utilities are beginning to explore storage with pilot programs,” Chang said of MISO’s situation, predicting that more storage will be constructed “when capacity is needed.”

MISO’s interconnection queue currently contains more than 2.5 GW of battery storage.

Consultant Mathew Roling said the rollout of battery storage in MISO would probably occur on a state-by-state basis, and battery solutions would be packaged with other technology or generation and not simply be standalone batteries.

National Renewable Energy Laboratory analyst Paul Denholm said four-hour batteries are close to becoming cost-competitive with peaking combustion turbines. Batteries’ ability to provide peaking capacity is especially heightened when they are paired with solar generation, he said.

Paul Mitchell, CEO of Indianapolis-based Energy Systems Network, said that while MISO hasn’t experienced much growth in battery storage systems, that will soon change.

“I think it’s finally going to come in full force,” he said, adding that “the biggest barrier remains the cost.”

Mitchell said battery storage costs aren’t quite as low as traditional generation, and current, 20-year storage contracts that promise to deliver energy at $300/kWh on average are essentially bets on the future value of storage systems — and they might be too optimistic.

“That’s putting a lot of trust in the future costs of energy storage systems. … That might be controversial to say,” he added.

MISO stakeholders in attendance participated in live polling during the panel, predicting that solid-state and vanadium redox flow batteries might emerge as the next dominant technologies.

Mitchell said he’s often privy to the innovations taking place at the Battery Innovation Center on Naval Support Activity Crane in southern Indiana. He cautioned that solid-state batteries right now are “teeny tiny” and nowhere near ready for factory manufacture. He said lithium-ion would continue to be the reigning battery option for at least the next five years.

“I think it’s going to take these technologies a long time to scale up … for the mass market of vehicles or in the grid,” he said.

Roling said the industry might be overlooking the benefits of pumped hydro storage in the rush to embrace battery storage.

“It’s water. It’s good for 100 years. It’s so natural it hurts,” he quipped.

Chang also pointed out that the environmental benefits of storage are system-dependent and only beneficial when batteries absorb and discharge energy from lower-emitting resources, displacing higher-emitting resources.

Roling said that unless MISO states become “anti-carbon,” battery storage in the footprint would never become cost-competitive. He said batteries would need “that social aspect” to be commercially viable.

To that, Chang pointed out that customers are increasingly calling for zero-carbon generation sources.

In another live poll, a majority of attendees predicted utility-scale batteries would become cost-competitive in MISO in about five to 10 years.

Stakeholders asked if storage might be able to flatten a potential duck curve before it even occurs.

Chang said the question was probably premature, as she believed wind would continue to dominate over solar generation in the footprint.

“I do think it’s unique here. I don’t think it’s the same as the West,” Chang said. “I don’t think we’re going to see the duck curve as quickly as in Texas or California. I think we have to be careful about taking one region and applying it to another.”