MISO successfully opened its wholesale markets to electric storage resources last week in compliance with FERC Order 841, the grid operator said Tuesday.

Effective Sept. 1, storage resources can participate in the RTO’s energy and operating reserves markets as supply or demand. MISO said the resources have the “operational characteristics that support reliability and resilience as the industry continues to transition the resource fleet.”

“We are excited to see this space grow with increasing member interest and participation, particularly as we continue to adapt to the accelerating resource transition,” Jessica Lucas, executive director of system operations, said in a statement. “With the introduction of electric storage resources to our market portfolio, we will continue to position MISO’s grid and its members as the grid of the future.”

Staff has developed a method that implements new storage-specific offer parameters required by FERC in a way that recognizes their unique physical and operational characteristics. The technology earned MISO its first patent last year from the U.S. Patent and Trademark Office.

The RTO said the participation model’s near-term benefits are “modest due to the small volume of storage resources.”

“However, the new model positions MISO ahead of the increased storage participation anticipated with higher penetration of renewables and distributed energy resources over the next five to 10 years,” it said.

MISO debuted the storage participation on its legacy market platform. It had originally requested that it be given until 2025 to fully incorporate storage on its new market platform. However, FERC ordered the grid operator to build the participation models on both of its market platforms. (See MISO: No Choice but to Double Up on 841 Compliance.)

The RTO said that that integrating storage offers into its markets would be better served under its new market platform and argued that being forced to put together two participation models to meet the deadline would stretch its resources.

CEO John Bear wrote to FERC in May to support a deferral, saying a 2022 launch could delay and “severely” compromise MISO’s “efforts to address growing reliability and resilience concerns and meet members’ carbon-reduction goals.”

The RTO reported over the summer that it was testing its new energy-storage participation software. Its electric storage model uses eight commitment statuses, including injecting, withdrawing or toggling between the two. Resources can also designate themselves as emergency injecting, emergency withdrawing, available, not participating or on outage.