MISO Aims to Accelerate Energy Storage Projects: Can States Match CAISO and ERCOT’s Speed?

MISO Aims to Accelerate Energy Storage Projects: Can Participating States Achieve Quick Interconnections Like CAISO and ERCOT?

February 18, 2025
By Rao Konidena
6 min read

A FlexGen battery energy storage system (BESS) in Fort Wayne, Indiana. Courtesy: FlexGen

The Midcontinent Independent System Operator (MISO) states should capitalize on the opportunity presented by the regional transmission organization (RTO) through its Expedited Resource Addition Study (ERAS) proposal, prioritizing energy storage as ERAS-eligible. MISO states play a crucial role in implementing ERAS to tackle resource adequacy challenges. MISO plans to submit its ERAS proposal to the Federal Energy Regulatory Commission (FERC) in mid-March, which presents an excellent chance to facilitate faster interconnections for energy storage resources, similar to the processes in California and Texas.

Background on MISO’s ERAS Proposal

MISO first introduced the ERAS proposal during discussions at the MISO Planning Advisory Committee (PAC) in November 2024. This proposal serves as a short-term solution to address capacity concerns while the backlog in the queue and study timeline are being reduced. MISO aims to expedite projects that are currently in the queue awaiting study, with the consent of MISO participants. Presently, there are 1,705 projects in MISO’s queue, with a total capacity of 312 gigawatts (GW), whereas MISO has an installed capacity of 202 GW. Without this proposal, MISO would continue to work through the backlog from previous queue cycles while also handling new submissions from the 2023 cycle. Due to the high volume of projects, MISO did not open the 2024 queue cycle, and the 2023 cycle was initiated in March 2024 instead of September 2023.

For renewable developers, MISO’s ERAS proposal is promising, as it plans to evaluate projects individually rather than in clusters. However, there are several requirements under ERAS, including stringent site control, large milestone payments, state acknowledgment, and a three-year commercial operation timeline.

Requirements for MISO’s ERAS Proposal

To qualify for ERAS, developers must first secure 100% site control. Additionally, MISO requires a non-refundable application deposit fee of $100,000 (compared to $7,000 for projects in the standard queue cycle) and a second milestone (M2) payment of $24,000 per megawatt (MW), as opposed to the current M2 milestone payment of $8,000 per MW. This ERAS proposal is designed to ensure that only serious projects with adequate financial support can advance, making it a premium fast-track option.

Furthermore, MISO mandates direct acknowledgment from state regulatory authorities as part of the ERAS proposal. States must identify which resources they wish to prioritize for resource adequacy purposes. Lastly, projects must achieve commercial operation within three years.

Concerns from MISO States

MISO emphasizes that for ERAS to be effective, projects must receive recognition from their state regulatory authorities. The Arkansas Public Service Commission (APSC) has voiced concerns regarding the need for MISO to tailor the ERAS proposal to align with the various priorities and criteria of different states, cautioning against a one-size-fits-all approach. APSC has suggested that MISO allow for flexibility in attestation qualification requirements and avoid an automatic sunset for ERAS. Currently, MISO proposes a sunset date of December 31, 2028, after which ERAS would no longer be available to prioritize resources for adequacy purposes.

The Organization of MISO States (OMS) Transmission Planning Work Group and Resources Work Group have jointly expressed that ERAS should remain a temporary measure and should not distract from ongoing improvements to MISO’s existing generation interconnection queue, which they believe should be the primary focus for addressing resource adequacy. They stress the importance of sufficient guardrails, transparency, and extended time for stakeholder input to prevent potential legal issues and ensure widespread state support.

Energy Storage as an Optimal ERAS-Eligible Resource

Energy storage projects should be prioritized under this ERAS proposal, as they can significantly contribute to resource adequacy across multiple MISO states. A key factor behind the higher integration of storage in California Independent System Operator (CAISO) and Electricity Reliability Council of Texas (ERCOT) regions is the capacity value provided by storage. Both CAISO and ERCOT have implemented measures to interconnect storage projects more rapidly to address their capacity issues. If MISO seeks to resolve its impending resource adequacy challenges, integrating storage is essential.

The ERAS proposal is particularly suitable for storage projects, as without it, these projects would remain in the queue for an additional three years awaiting study. The 2024 OMS MISO Survey indicates that MISO could face a capacity shortfall of 2.7 GW or a surplus of 1.1 GW, depending on the volume of generation that can be interconnected. While the OMS Work Group’s comments emphasize procedural safeguards, they overlook a critical opportunity: energy storage can immediately bolster resource adequacy and should be prioritized.

MISO’s latest Regional Resource Assessment report indicates an increasing demand for fast-ramping resources beyond 2030. The analysis suggests that four-hour batteries may not deliver the same capacity value as long-duration batteries in the years after 2030, while the ERAS proposal expires in 2028. Currently, most energy storage projects awaiting study in MISO’s queue consist of four-hour-duration batteries linked to solar or wind sites. Therefore, MISO states should prioritize the storage projects already in the queue, rather than assuming that future needs dictate prioritization.

Some may argue that MISO’s long-term requirements point to a need for long-duration storage beyond 2030. However, the immediate focus should be on meeting near-term reliability demands, for which four-hour batteries are well-equipped. While addressing MISO’s queue remains important, the overwhelming number of 1,705 projects makes it unfeasible to process them all within the necessary timeframe to meet urgent capacity needs in the next three years. Unless MISO prioritizes and expedites serious projects that are currently stalled behind less critical ones, the queue will remain unmanageable. This represents a critical opportunity for MISO to streamline the queue.

Next Steps

MISO is set to file its ERAS proposal with FERC next month. This is a timely proposal for states to support; if they present a unified response at FERC following MISO’s filing, the current FERC Chairman Mark Christie and the other Commissioners are likely to approve MISO’s proposal. MISO and the participating states are effectively driving the push for resource adequacy with the backing of renewable developers. MISO states must act promptly to advocate for the prioritization of energy storage under ERAS. Without decisive action, the next capacity crisis could be preventable—but only if they seize this opportunity.