
The results of this study underscore the value of MISO. The larger the region we interconnect across, the lower the aggregate cost. On the whole, this will save ratepayers billions annually.
This project attempted to answer the fundamental question: how do we achieve 100% renewables across the MISO region while not breaking the bank?
In November 2018, the MN Solar Pathways project released the Solar Potential Analysis (SPA) Report on the generation costs of wind and solar in Minnesota looking toward 2030 and 2050. Part of the feedback to come from the SPA process was to run a similar analysis for the entire Midcontinent Independent System Operator (MISO) service territory in an effort to model the day-to-day realities of Minnesota’s role in a larger network.
Why it was important to consider 100% across MISO:
- Environmental prerogative
- Socioeconomic prerogative
- Helps to set a realistic high water mark for costs when firmly meeting load with high levels of renewables.
- We’ve shown energy transformation can be cost-effective across MN using optimized capacity expansion and dispatch. Will these same things hold true for MISO?
- Solar and wind resource have different spatial and temporal characteristics across the territory: how does this affect cost?
- What value does an interconnected MISO region deliver in terms of reduced energy cost relative to smaller sub-regions?
- How does a 100% renewable optimized capacity expansion portfolio change with the cost of system components over time?
The Analysis: The project team used the Clean Power Transformation (CPT) model to optimize capacity expansion and dispatch across 14 distinct geographic zones, each with their own unique load and renewable resource characteristics. Optimal capacities of wind, PV and storage are identified and change depending on the underlying cost assumptions. In light of this, four cost scenarios were derived from the latest (2019) NREL Annual Technology Baseline (ATB).
Key takeaways from the report
Project partner Clean Power Research completed the MISO-wide Solar Potential Analysis, and report lead Marc Perez discusses the results.
Implicit storage (overbuilding + curtailment) is highly cost-effective in every case.
Wind + PV hybrid resourcing is significantly cheaper than either alone due to seasonal resource anticorrelations, even in areas that have a dominant resource.
Technological costs change the LCOEs and the technological mix:
- Raise wind cost relative to PV cost, decrease optimal wind percentage
- Raise storage cost relative to renewables, increase implicit storage use
- Confidence and consensus surrounding cost will help the planning process
In 2050, high technological development scenarios favor PV in most regions given the drastic projected reduction in CapEx
- This is despite a very strong wind resource in the northern part of MISO territory
- Exceptions include LRZ zones 3 and 7 where the very strong wind resource tilts the balance
The larger the region we interconnect across, the lower the aggregate cost. On the whole this will save ratepayers billions annually.
Allowing 5% gas or some other dispatchable gas to perform some of the work otherwise done by storage (both implicit and real). It may also be more acceptable as it correspondingly reduces the amount of optimal curtailment.
Use the MISO-wide Solar Potential Analysis web app to explore results
A web application has been developed for users to change assumptions related to cost and geographic scope to reveal how these changed assumptions affect optimal capacity allocations and dispatch.
About MN Solar Pathways
The initiative, sponsored by the U.S. Department of Energy Solar Energy Technologies Office, is a three-year project designed to explore least-risk, best-value strategies for meeting the State of Minnesota’s solar goals. As part of this aim, the Pathways Team is modeling renewable generation costs, examining ways to streamline interconnection, and evaluating technologies that can increase solar hosting capacity on the distribution grid.
MN Solar Pathways is led by the Minnesota Department of Commerce, Great Plains Institute, Center for Energy and Environment, Clean Energy Resource Teams, and Clean Power Research. 20 other organizations, from utilities to advocacy groups and from corporations to local governments, have contributed their time and expertise in the review and creation of reports for the initiative.

