New Analysis Quantifies Capacity Benefits of Grid United and ALLETE's North Plains Connector Interregional Transmission Line

Grid United, a leading developer of high voltage transmission infrastructure, today announced the results of a comprehensive study conducted by Astrapé Consulting, highlighting the substantial reliability and capacity benefits of connecting the Western and Eastern Interconnections across three independent system markets – Western Electricity Coordinating Council (WECC), Southwest Power Pool (SPP), and the Midcontinent Independent System Operator (MISO).

Grid United and ALLETE, Inc. (NYSE:ALE) are developing North Plains Connector (NPC), a 415-mile and up to 525 kilovolt high voltage direct current (HVDC) transmission line that would connect the western and eastern electric grids in Montana and North Dakota. NPC would be the first HVDC transmission connection between three regional U.S. electricity markets — MISO, SPP, and WECC.

The study, which modeled North Plains Connector as two 1,500 MW HVDC lines connecting SPP and MISO to the Western electric grid, quantified the project's ability to increase power system reliability using the same framework employed by utilities and grid operators. When the bi-directional nature of the project as well as the seasonal diversity between the three regions are considered, the analysis found that NPC will unlock 3,550 MW of capacity across the three systems. Summed across all three regions, this total is greater than the physical capacity of the project itself. This capacity benefit represents the amount of additional demand that can be served without degrading reliability standards.

Importantly, the study quantifies the benefits that can be obtained by connecting meteorologically diverse regions whose peak need for electricity occurs at different times of day or in different seasons. Leveraging this difference in generation and load profiles improves the reliability of the grid on both sides of the project without adding any new generating capacity and allows the project to add an outsized amount of reliability benefit relative to its physical capacity.

"We are extremely encouraged by the results of this study, which underscore the critical role North Plains Connector will play in mitigating the effects of extreme weather events by more than doubling existing transfer capacity between the Eastern and Western Interconnections," said Julie Pierce, Vice President of Strategy and Planning of ALLETE. "By increasing reliability and facilitating the efficient transfer of power between regions, NPC will enhance power system resilience and capacity."

"This study shows that the reliability benefits of an interregional transmission project can be quantified using the same methodologies we use for new generating facilities and that those benefits are worth quantifying," said Kris Zadlo, President and Chief Technical Officer of Grid United. "We hope it sets a precedent for more comprehensive analysis regarding the benefits of interregional transmission projects. By shedding light on how grid-connecting projects like NPC enhance reliability and reduce the risk of power outages, we can build a better connected, more resilient grid for the future."

Visit www.gridunited.com/resources to read the full report.

About Grid United

Grid United is an independent transmission company aiming to develop next-generation energy infrastructure to create a more resilient and efficient electric system to the benefit of all consumers. For more information, visit www.gridunited.com

About ALLETE

ALLETE, Inc. is an energy company headquartered in Duluth, Minnesota. In addition to its electric utilities, Minnesota Power and Superior Water, Light and Power of Wisconsin, ALLETE owns ALLETE Clean Energy, based in Duluth; BNI Energy in Bismarck, North Dakota; and New Energy Equity, headquartered in Annapolis, Maryland; and has an 8% equity interest in the American Transmission Co. More information about ALLETE is available at www.allete.com.

ALE-CORP The statements contained in this release and statements that ALLETE may make orally in connection with this release that are not historical facts, are forward-looking statements. Actual results may differ materially from those projected in the forward-looking statements. These forward-looking statements involve risks and uncertainties and investors are directed to the risks discussed in documents filed by ALLETE with the Securities and Exchange Commission.

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