ALLETE : Investor Presentation - June

Guggenheim Partners, LLC

June 17, 2021

Forward looking statement

Any statements contained in this presentation and statements that ALLETE, Inc. representatives may make orally in connection with this presentation 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, Inc. with the Securities and Exchange Commission.

ALLETE's presentation and other communications may include certain non-Generally Accepted Accounting Principles (GAAP) financial measures. A "non-GAAP financial measure" is defined as a numerical measure of a company's financial performance, financial position or cash flows that excludes (or includes) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP in the company's financial statements.

Non-GAAP financial measures utilized by the Company may include a presentation of earnings (loss) per share and earnings. ALLETE's management believes that non-GAAP financial measures provide useful information to investors by removing the effect of variances in GAAP reported results of operations that are not indicative of changes in the fundamental earnings power of the Company's operations. Management believes that the presentation of the non-GAAP financial measures is appropriate and enables investors and analysts to more accurately compare the company's ongoing financial performance over the periods presented. Non-GAAP measures to the most directly comparable GAAP measure, if presented, is included in the appendix.

This presentation was prepared as of June 17, 2021, and ALLETE, Inc. assumes no obligation to update the information or the forward-looking statements contained herein. The 2021 outlook contained herein was provided, and is as of May 6, 2021.

For more information, contact:

Vince Meyer

Director, Investor Relations and Treasury

1. [e-mail]

Visit our website at www.allete.com	2

ALLETE's sustainability in action strategy

delivers growth

Expand renewable sources of energy

• Currently ranked second among investor-owned utilities for investment in renewable energy based on market capitalization
• Minnesota Power #1 in Minnesota, and #2 in Midwest as a renewable energy provider

Reduce overall carbon emissions

• Minnesota Power
• • Retired/idled seven of nine coal facilities
  • Renewable goals of 50% at end of 2020, and 70% by 2030
  • Coal-freeby 2035 and 100% carbon-free by 2050
• ALLETE Clean Energy
• • 1,500 MW helping utilities and C&I customers achieve sustainability goals nationwide

Strengthen the electric grid

• Investing in infrastructure for managing the delivery of increasing amounts of renewable energy, and enhancing the resiliency and reliability of the grid

Adopt innovative solutions

• Reducing water use, investing in more weather resistant infrastructure, identify alternative low-orzero-carbon fuels and carbon capture and sequestration technology

Workplace		Community		Customers

• 2020 Women on Board Winner for Board Gender Diversity
• Minnesota Power & ALLETE Clean Energy named Yellow Ribbon Companies
• Commitment to advancing DE&I
• Proactive and deliberate COVID-19 response

• Partnering with diverse suppliers
• Corporate funding and employee volunteerism to those in need - and addressing the opportunity gap
• Full commitment to regional economies and host communities

• Well positioned to serve the C&I customer segment
• Strong focus on customer ESG & competitiveness needs
• Donating Level 2 electric vehicle charging stations to business customers

Published first EEI report June 2020 - first overall Corporate Sustainability Report March 2021 - Includes TCFD, SASB, EEI, and DE&I components

3

ALLETE is uniquely positioned to leverage clean energy trends - setting the stage for future growth

Key Macro Drivers

• Policy
• ESG
• Regulation
• Technology
• Markets

New Opportunities

• Significant increase in decarbonization program/technology investment
• Grid hardening and renewable enabling investments
• Beneficial electrification

Our size is an advantage that allows nimbleness; small opportunities move the needle

Ability to leverage vast experience with industrial customers; C&I customers are at the forefront of the cleaner energy movement

Creative, adaptive and innovative human capital is a differentiator that enables targeted returns

Strong and respected reputation with key stakeholder groups, including broad industry reach and expanding investment partnerships

Capabilities include large renewable project execution, as well as platform asset ownership and optimization

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Relative to size, ALLETE is one of the largest investors in renewables

Solar and Wind Capacity as a Percent of Market Cap (MW / US$ Market Cap)¹

56%

49%

10%

ALLETE continues to evolve as a market leader, retaining its #2 ranking in renewable investment

Source: Company public filings, SNL, Press Releases, Bloomberg market data as of 26-Feb-21

Note: Includes both regulated and unregulated wind and solar net generation capacity.

1 Calculated as solar and wind net owned operating capacity / market cap. Excludes development pipelines.

Key Trends in the U.S. Renewables Sector and Overview of ALE Portfolio	5