15-State Grid Operator Issues Troubling Outlook for Electricity Supply

The Midcontinent Independent System Operator (MISO) released “MISO’s Response to the Reliability Imperative,” which is updated periodically to reflect changing conditions in the 15-state MISO region that extends through the middle of the U.S. as well as into Manitoba, Canada (blue in the map).[i] MISO controls the electric generation and transmission assets within its region, which is the largest geographic footprint of any grid operator in the nation, and serves 45 million people. 

MISO’s new report explains the troubling outlook for electric reliability in its footprint unless urgent action is taken.  The main reasons for this warning are (1) the pace of premature retirements of dispatchable fossil generation and (2) the resulting loss of accredited capacity and reliability attributes.  We thought the simplest way to give readers a flavor for the 31-page report is to provide a few excerpts:


  • “There are immediate and serious challenges to the reliability of our region’s electric grid … the transition that is underway to get to a decarbonized end state is posing material, adverse challenges to electric reliability.”

  • “A key risk is that many existing ‘dispatchable’ resources that can be turned on and off and adjusted as needed are being replaced with weather-dependent resources such as wind and solar that have materially different characteristics and capabilities.”
  • “Over the last 10-plus years, surplus reserve margins in MISO have been exhausted through load growth and unit retirements … the region only averted a capacity shortfall in 2023 because some planned generation retirements were postponed, and some additional capacity was made available to MISO. However, MISO cannot count on such actions being repeated going forward.”
  • “Incremental load growth due to electric vehicles and other aspects of electrification is exerting new pressure on the grid.
  • “While electricity demand has been flat for many years, it is expected to increase due to the electrification of other sectors of the economy.”
  • “ … a large number of fully approved and much-needed new generation projects are being delayed by supply chain issues, regulatory issues, and other external factors beyond MISO’s control … upward of 50 GW of fully approved new generation projects could be delayed by external factors beyond MISO’s control is deeply concerning.”

Need for Dispatchable Electricity Sources

  • “Until new technologies become viable, we will continue to need dispatchable resources for reliability purposes.”

  • “The new weather-dependent resources that are being built, such as wind and solar, do not provide the same critical reliability attributes as the conventional dispatchable coal and natural gas resources that are being retired.”
  • “No single type of resource provides every needed system attribute; the needs of the system have always been met by a fleet of diverse resources. However, in many instances, the new weather-dependent resources that are being built today do not have the same characteristics as the dispatchable resources they are replacing.”
  • “Many dispatchable resources that provide critical reliability attributes are retiring prematurely due to environmental regulations and clean-energy policies.”

Threat from EPA Regulations

  • “Other drivers of the region’s tightening supply picture include … U.S. Environmental Protection Agency (EPA) regulations that prompt existing coal and gas resources to retire sooner than they otherwise would.”
  • “In the view of MISO, several other grid operators, and numerous utilities and states, the U.S. Environmental Protection Agency (EPA) has issued a number of regulations that could threaten reliability in the MISO region and beyond.”
  • “In May 2023, for example, EPA proposed a rule to regulate carbon emissions from all existing coal plants, certain existing gas plants and all new gas plants. As proposed, the rule would require existing coal and gas resources to either retire by certain dates or else retrofit with costly, emerging technologies such as carbon-capture and storage (CCS) or co-firing with low-carbon hydrogen.”
  • “If EPA’s proposed rule drives coal and gas resources to retire before enough replacement capacity is built with the critical attributes the system needs, grid reliability will be compromised. The proposed rule may also have a chilling effect on attracting the capital investment needed to build new dispatchable resources.”

Loss of Reliability Attributes

  • “Reliably navigating the energy transition requires more than just having sufficient generating capacity; it also requires urgent action to avoid a looming shortage of broader system reliability attributes.”

  • “While wind and solar produce needed clean energy, they lack certain key reliability attributes that are needed to keep the grid reliable every hour of the year.”
  • “ … because new wind and solar resources have significantly lower accreditation values than the conventional resources that utilities and states plan to retire …, the region’s level of accredited capacity … is forecast to decline by a net 32 GW by 2042.”
  • “The transition to a low- to no-carbon electric grid also poses risks in the realm of fuel assurance. These risks impact conventional coal and gas resources that provide reliability attributes such as system adequacy, flexibility and system stability that may be becoming scarce due to fleet change.”

The MISO report adds to the increasingly dire warnings from the North American Electric Reliability Corporation, other grid operators, FERC commissioners, state utility commissioners and others.  The report ended by pointing out that “the responsibility for ensuring grid reliability and resource adequacy in the MISO region is not MISO’s alone. It is shared among Load Serving Entities (LSEs), states and MISO, each of which have designated roles to play.”  We would add FERC and Congress to the list of those responsible for ensuring that tens of millions of Americans will not face a future marked by rolling blackouts. 

[i] MISO’s region in the U.S. includes all or parts of Montana, North Dakota, South Dakota, Minnesota, Iowa, Wisconsin, Michigan, Indiana, Illinois, Missouri, Kentucky, Arkansas, Mississippi, Louisiana, and Texas.

For additional information about the nation’s fleet of coal-fired power plants, please visit www.AmericasPower.org.