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Economic Planning

MISO's economic planning process helps develop transmission plans that offer MISO customers better access to the lowest electric energy costs. Utilizing a regional perspective, MISO and stakeholders identify near-term transmission issues, long-term economic opportunities and new network upgrades to enhance overall efficiency. Project solutions studied in the economic planning process are evaluated for economic benefit based on the adjusted production cost (APC) savings. For details on the planning process and APC methodology, see the related documents below. 


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Business Need/Study Scope

As the MISO fleet continues to shift away from large thermal units to geographically dispersed inverter-based renewables, it is expected that addressing non-thermal system limitations will begin playing a larger role in ensuring reliable operation of the system. MISO’s economic planning process has historically focused on thermal limits for its market constraint modeling, with non-thermal limits simply being modeled at their currently defined ratings. To accurately reflect the future MISO energy market, reliability assessments must be performed to determine if any updated or new non-thermal limits should be incorporated into the economic models.

The North Region Targeted Study is an informational study in which MISO evaluates system limitations caused by non-thermal constraints between the high renewable penetration northwestern areas of MISO and load centers in eastern areas of MISO. Findings from this study will be used to inform future transmission planning initiatives and improve existing economic evaluation processes such as the Market Congestion Planning Study (MCPS).

Evaluating non-thermal issues in economic modeling will allow future economic studies to better capture how the market would operate in any potential future system scenario. As MISO’s generation fleet converts from traditional large thermal units to inverter based intermittent and distributed renewables, this process will become increasingly important in maintaining the most efficient and reliable bulk electric system.

Outlook/Next Steps

The MISO generator fleet is projected to change significantly in the coming years, moving away from large thermal units with high inertia to inverter-based technologies. The North Region Targeted Study was a first step in re-evaluating MISO’s standard economic planning processes to ensure that all issues that will be encountered in the future are considered. An iterative process between reliability and economic analyses is required to address system needs due to changing generation fleet.

The process and findings from this study will be used to further investigate non-thermal issues in the MISO North region as a part of the Long-Range Transmission Planning effort in MTEP21.

In upcoming studies, additional analysis will be conducted to identify solutions that improve voltage stability in the MISO North region. MISO will conduct both voltage and transient stability analysis to reveal weak grid areas that have high penetration of inverter-based resources. Concurrently, options to quantify reliability benefits provided by any projects that mitigate these non-thermal issues will be explored.


NRTS Study Scope presented at the February 2020 PAC

NRTS Study Findings presented at the May 2020 MCPS TSTF

NRTS Study Findings presented at the August 2020MCPS TSTF

North Region Targeted Study report

Business Need/Study Scope

In early 2019, MISO submitted updates to the current MEP cost allocation methodology to include the avoided cost of future MISO-SPP Settlement Agreement payments as a benefit metric. Shortly after, MISO received requests from various Stakeholders to examine transmission line alternatives to the MISO-SPP Settlement Agreement.  MISO began studying the economic benefit potential of various transmission lines against the cost of future settlement payments. The objective of this analysis was to determine if a transmission project would offer a better value to MISO’s membership than the current MISO-SPP Settlement Agreement and if a higher transfer capability between the MISO sub-regions would result in increased economic benefits.

Outlook/Next Steps

Although MISO concluded the North-South Interface Study in the spring of 2020 with the MTEP19 project scope, MISO anticipates further analysis in MTEP21. The three main reasons for concluding the current study are (1) MISO has continuously collaborated with SPP and The Joint Parties and plans to continue that communication into the MTEP21 time period (2) Stakeholders would like MISO to consider benefit metrics beyond APC savings and avoided settlement costs to capture all of the benefits a transmission solution would provide (3) At the time of conclusion, the Tariff updates which included settlement agreement cost avoidance as a benefit metric were still pending FERC approval.


North-South Interface Study detailed scoping & process presented at the April 2019 MCPS TSTF.

North-South Interface Study conclusion & next steps presented at the May 2020 MCPS TSTF