Dive Brief:

• The Midcontinent ISO is not prepared for a slate of medium-term energy storage projects being considered and will need to make changes to its tariff to incorporate the resources, RTO Insider reports.
• MISO's markets already incorporate short-term storage reserves as well as longer-term pumped hydro, but battery storage which could supply significant energy for several hours has not been included and the grid operator is seeing increasing interest in the projects.
• Indianapolis Power & Light in June announced plans for a 20 MW utility-scale battery project designed to boost reliability and lower customer costs. The battery would provide energy equivalent to 40 MW of flexible resource to the electric grid, and is expected online this summer. 

Dive Insight:

MISO officials say they are seeing increased interest in energy storage projects within the 15-state system, but so far have no place for them in the grid operator's tariff.

“We’ve had kind of fits and starts with this issue," MISO External Affairs Policy Advisor Jennifer Richardson said. "But as far as having a clear policy, well, that’s never happened."

According to a report from RTO Insider, the agency has been approached by several companies looking to develop energy storage projects, but right now the tariff contemplates only short-term resources providing energy for less than an hour, and longer-term pumped projects. The middle ground now being contemplated would require changes to the tariff, including decisions on which side of the meter the resources will operate.

“Medium-term storage is gaining a lot of interest,” MISO Principal Advisor of Market Development and Analysis Yonghong Chen told RTO Insider. “Storage is a broad range of emerging technology … it can be complicated."

At least one project is in development and expected to be online in a few months. AES Corp. subsidiary IPL's facility will be MISO's first utility-scale storage project. Located in Marion County, Indiana, the battery storage facility will deliver enhanced grid reliability and ancillary services, according to the utility, including peak power supply, and will help balance supply and demand to save customers money.

"Energy storage is a smart way to cost-effectively address a number of grid challenges including variability of energy supply and demand, while also improving the reliability of the grid," said Kelly Huntington, IPL President and CEO.