By Amanda Durish Cook

The Upper Midwest needs more transmission, more technology and preservation of some dispatchable generation for the sake of reliability, the CapX2050 study concluded last week.

The 10 Minnesota utilities behind the effort drew three major takeaways from the study:

• More transmission infrastructure will be necessary in the Upper Midwest to accommodate resource transition.
• Non-dispatchable resources alone can’t meet all energy requirements, so some traditional power plants will still be necessary.
• Real-time operational demands will become trickier to manage and will require new procedures.

Building on the CapX2020 transmission effort focused on 2020 reliability needs, the CapX2050 study addresses how the grid can handle widescale reductions in carbon emissions by 2050. (See Minnesota Utilities Reunite for CapX2050 Study.) Like the 2020 effort, the 2050 study concentrated on the transmission system that serves Minnesota, eastern South Dakota and North Dakota, western Wisconsin and the surrounding areas.

The study’s report said grid support in the form of ancillary services will be needed in areas where large, dispatchable generation is retired. New transmission technology and storage resources will be required to deliver ancillary services.

The group said its findings track with conclusions from MISO’s ongoing Renewable Integration Impact Assessment, which most recently showed that the RTO can operate on 50% renewable generation if it endorses dramatically more transmission and increases reserve requirements while its members embrace new technologies. (See MISO Renewable Study Shows More Tx, Tech Needed.)

“The variability of the output of non-dispatchable resources, even within a single day, could lead to several thousands of [megawatts] being transferred across the transmission system, with reversals in direction of flow occurring in an equal but opposite magnitude during the same day,” the report warned. “Operating techniques, transmission infrastructure and analysis tools will need to become more sophisticated to more accurately identify and adjust in real-time to deal with these changes.”

The utilities said that simply adding more non-dispatchable resources cannot solve the problem of sometimes deficient energy supply.

“Abrupt changes in weather, including prolonged extreme weather conditions, sudden changes in consumer demand, or disturbances on the transmission system (i.e., outages) will increasingly challenge the ability of the electric grid to provide a continuous supply of energy as more non-dispatchable resources are added,” the report said. It added that maintaining some dispatchable resources and adding energy storage can keep the transmission system reliable.

In what should be déjà vu for MISO planners, the CapX2050 report also called for a “long-term comprehensive regional transmission plan.” The Organization of MISO States has been pressing the RTO for two years to develop a long-term transmission package to accommodate growth of policy-driven generation resources. (See MISO Cracks Door on Long-term Tx Planning.) The report reminded MISO that “transmission expansion has been shown to be cost-effective when considered as part of a larger market.”

At this point, the CapX2050 utilities aren’t calling for any specific transmission projects. CapX2020 culminated in an 800-mile, grid expansion in the Upper Midwest, including four 345-kV transmission lines in Minnesota, North Dakota, South Dakota and Wisconsin and a 230-kV line in northern Minnesota.

Great River Energy spokesperson Jenny Mattson said that while future studies under CapX2050 aren’t being ruled out, none are planned so far.

“Though there is no time frame for additional studies, we’ll continue to evaluate the system in partnership with other utilities and stakeholders, including legislators, regulators, communities and MISO,” Mattson said in an email to RTO Insider.

The utilities also said they’re “ready to engage with public and stakeholders” on planning for new transmission.