Form 8-K - Current report

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 28, 2024

NorthWestern Energy Group, Inc.

(Exact name of registrant as specified in its charter)

Delaware

000-56598

93-2020320

(State or other jurisdiction of
incorporation or organization)

(Commission File Number)

(I.R.S. Employer Identification No.)

3010 W. 69th Street

Sioux Falls

South Dakota

57108

(Address of principal executive offices)

(Zip Code)

Registrant’s telephone number, including area code: 605-978-2900

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:


Registrant	Title of each class	Trading Symbol(s)	Name of each exchange on which registered
NorthWestern Energy Group, Inc.	Common stock	NWE	Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging Growth Company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

☐

Item 2.02 Results of Operations and Financial Condition

On October 28, 2024, NorthWestern Energy Group, Inc. d/b/a NorthWestern Energy (Nasdaq: NWE) (the “Company”) issued a press release (the “Press Release”) discussing financial results for the quarter ended September 30, 2024. As announced in the Press Release, the Company has adjusted its earnings guidance for 2024 to $3.32 to $3.47 (from original guidance of $3.42 to $3.62). The Press Release is furnished as Exhibit 99.1 hereto and is incorporated herein by reference.

The information in this Current Report on Form 8-K provided under Item 2.02 shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that Section. The information provided under Item 2.02 in this Current Report shall not be incorporated by reference into any registration statement or other document pursuant to the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing.

Item 7.01 Regulation FD Disclosure.

As previously announced and as stated in the Press Release, the Company will host an investor earnings webcast on October 30, 2024, at 3:00 p.m. Eastern time to review its financial results for the quarter ending September 30, 2024. During the conference call, Brian B. Bird, president and chief executive officer, and Crystal D. Lail, vice president and chief financial officer of the Company, will make a slide presentation (the "Investor Webcast Presentation") concerning the Company's financial results.

The investor earnings webcast can be accessed from the Company’s website at www.northwesternenergy.com/earnings-registration. To listen and view the slideshow presentation, please go to the site at least 10 minutes in advance of the webcast to register. An archived webcast will be available shortly after the event and will be available for one year.

A copy of the Investor Webcast Presentation is being furnished pursuant to Regulation FD as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference. The information in the presentation shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section. Furthermore, the presentation shall not be deemed to be incorporated by reference into the Company's filings under the Securities Act of 1933, as amended, or under the Securities Exchange Act of 1934, as amended, except as set forth with respect thereto in any such filing.

Item 9.01 Financial Statements and Exhibits.


Exhibit No.						Description of Document
99.1*						Press Release, dated October 28, 2024
99.2*						Investor Webcast Presentation, dated October 30, 2024
104						Cover Page Interactive Data File – the cover page XBRL tags are embedded within the Inline XBRL document

* filed herewith

Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.


						NorthWestern Energy Group, Inc.

			By:			/s/ Timothy P. Olson
						Timothy P. Olson
						Corporate Secretary

Date: October 29, 2024


			NorthWestern Energy Group, Inc. d/b/a NorthWestern Energy 3010 W. 69th Street Sioux Falls, SD 57108 www.northwesternenergy.com

FOR IMMEDIATE RELEASE

NorthWestern Reports Third Quarter 2024 Financial Results

•Third quarter 2024 GAAP EPS of $0.76, compared to $0.48 in 2023

•Third quarter 2024 adjusted non-GAAP EPS of $0.65, compared to $0.49 in 2023

•Announces $0.65 per share quarterly dividend

•Revises 2024 earnings guidance in light of delayed Montana interim rate decision

BUTTE, MT / SIOUX FALLS, SD - October 28, 2024 - NorthWestern Energy Group, Inc. d/b/a NorthWestern

Energy (Nasdaq: NWE) reported financial results for the third quarter 2024. Net income for the period was $46.8 million, or $0.76 per diluted share, as compared with net income of $29.3 million, or $0.48 per diluted share, for the same period in 2023. NorthWestern’s third quarter 2024 non-GAAP net income and non-GAAP earnings per share were $39.7 million and $0.65, respectively, compared to $30.0 million and $0.49 in 2023. See “Adjusted Non-GAAP Earnings” and “Non-GAAP Financial Measures” sections below for more information on these measures.

Third quarter earnings were driven by rate relief in Montana and South Dakota, higher electric transmission revenues, and an income tax benefit, partly offset by mild weather, insurance costs, depreciation, and interest expense.

"As we continue to execute on our strategic priorities, we are pleased to report another quarter of solid earnings growth," said Brian Bird, President and CEO. "We remain committed to providing reliable and affordable energy for our customers. Yellowstone County Generating Station began to serve customers in October, providing critical capacity as we go into the winter season. Meanwhile, we are actively working with the commissions in Montana, South Dakota, and Nebraska to advance our rate reviews and ensure timely recovery of the substantial investments we’ve made on our customers behalf."

THIRD QUARTER 2024 COMPARED TO THIRD QUARTER 2023

The increase in net income was primarily due to new base rates in Montana and South Dakota, electric transmission revenues, electric retail volumes, Montana property tax tracker collections, lower non-recoverable Montana electric supply costs, and an income tax benefit from a change to the gas repairs safe harbor method. These were offset in part by natural gas retail volumes, depreciation, operating, administrative and general costs, and interest expense. Diluted earnings per share increased as a result of higher net income but was partially offset by increased average shares outstanding due to equity issuances during 2023.

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 2

EARNINGS GUIDANCE

We are revising our 2024 non-GAAP EPS guidance range to $3.32 to $3.47 from our original guidance of $3.42 to $3.62 in light of the delay in interim rate relief in our Montana rate review. The revised 2024 midpoint of approximately $3.40 represents a 4% increase off our 2023 non-GAAP earnings per share of $3.27.

This guidance is based upon, but not limited to, the following major assumptions:

• Normal weather in our service territories;

• Interim rates in Montana in December 2024;

• An effective income tax rate of approximately 9%-11%; and

• Diluted average shares outstanding of approximately 61.4 million.

We are also affirming our long-term (5 year) diluted earnings per share growth guidance of 4% to 6% from a 2022 base year of $3.18 diluted earnings per share on a non-GAAP basis. We expect rate base growth of 4% to 6%. Our current capital investment program is sized to provide for no equity issuances. Future generation capacity additions or other strategic opportunities may require equity financing.

Dividend Declared

NorthWestern Energy Group's Board of Directors declared a quarterly common stock dividend of $0.65 per share payable December 31, 2024 to common shareholders of record as of December 13, 2024. While currently above our targeted 60-70 percent dividend payout range, over the longer-term we expect to maintain a payout within the range.

Additional information regarding this release can be found in the earnings presentation at
https://www.northwesternenergy.com/investors/earnings

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NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 3

COMPANY UPDATES

Yellowstone County 175 MW plant

Construction of the new generation facility was substantially completed and the plant placed in service in October 2024. The lawsuit challenging the Yellowstone County Generating Station air quality permit, which required us to suspend construction activities for a period of time, as well as additional related legal and construction challenges, delayed the project timing and have increased costs. As of September 30, 2024, total costs of approximately $305.6 million have been incurred, with expected total costs of approximately $310.0 million to $320.0 million.

Regulatory Update

Rate reviews are necessary to recover the cost of providing safe, reliable service, while contributing to earnings growth and achieving our financial objectives. We regularly review the need for electric and natural gas rate relief in each state in which we provide service. Our ongoing rate review activity includes the following:

Montana Rate Review - In July 2024, we filed a Montana electric and natural gas rate review with the Montana Public Service Commission (MPSC). The filing requests a base rate annual revenue increase of $156.5 million for electric and $28.6 million for natural gas. Our request is based on a return on equity of 10.80 percent with a capital structure including 46.81 percent equity, and forecasted 2024 electric and natural gas rate base of $3.45 billion and $731.9 million, respectively. The electric rate base investment includes the 175-megawatt natural gas-fired Yellowstone County Generating Station, which was placed in service in October 2024.

Our filing included a request for interim base rates to be effective October 1, 2024. Implementation of interim base rates, if any, has been delayed beyond our requested effective date as the MPSC has not yet made a decision on the interim rate request.

The MPSC has developed its procedural schedule for our rate review request including a hearing scheduled to commence on April 22, 2025. If a final order is not received by May 23, 2025, which is 270 days from acceptance of our filing, we intend to implement, as permitted by the MPSC regulations, our requested rates, which will be subject to refund, until a final order is received.

South Dakota Natural Gas Rate Review - In June 2024, we filed a natural gas rate review with the South Dakota Public Utilities Commission. The filing requests a base rate annual revenue increase of $6.0 million. Our request is based on a return on equity of 10.70 percent, a capital structure including 53.13 percent equity, and rate base of $95.6 million. If a final order is not received by December 21, 2024, interim base rates may go into effect.

Nebraska Natural Gas Rate Review - In June 2024, we filed a natural gas rate review with the Nebraska Public Service Commission (NPSC). The filing requests a base rate annual revenue increase of $3.6 million. Our request is based on a return on equity of 10.70 percent, a capital structure including 53.13 percent equity, and rate base of $47.4 million. Interim rates, which increased base natural gas rates $2.3 million, were implemented on October 1, 2024. Interim rates will remain in effect on a refundable basis until the NPSC issues a final order.

Environmental Protection Agency (EPA) Rules

On April 25, 2024, the EPA released Greenhouse Gas (GHG) Rules for existing coal-fired facilities and new coal and natural gas-fired facilities as well as Mercury and Air Toxics Standard (MATS) Rules. Compliance with the rules will require expensive upgrades at Colstrip Units 3 and 4 with proposed compliance dates that may not be achievable and / or require technology that is unproven, resulting in significant impacts to costs of the facilities. The final MATS and GHG Rules require compliance as early as 2027 and 2032, respectively.

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 4

Acquisition of Energy West Montana Assets

On July 29, 2024, we entered into an Asset Purchase Agreement with Hope Utilities to acquire its Energy West natural gas utility distribution system and operations serving approximately 33,000 customers located near Great Falls, Cut Bank, and West Yellowstone, Montana for approximately $39.0 million in cash, subject to certain working capital and other agreed upon closing adjustments. The transaction is subject to a number of customary closing conditions, including MPSC approval, and we expect the acquisition to be completed by the end of the first quarter of 2025.

Colstrip - Puget Sound Energy Transaction

On July 30, 2024, we entered into a definitive agreement (the Agreement) with Puget Sound Energy (Puget) to acquire Puget's 25 percent interest in each of Units 3 and 4 (collectively representing 370 megawatts) at the Colstrip Generating Station for $0. The acquisition would be effective December 31, 2025, subject to the satisfaction of the closing conditions contained within the Agreement. Under the terms of the Agreement, we will be responsible for operating costs starting on January 1, 2026; while Puget will retain responsibility for its pre-closing share of environmental and pension liabilities attributed to events or conditions existing prior to the closing of the transaction and for any future decommission and demolition costs associated with the existing facilities that comprise Puget's interest. The Agreement is subject to customary conditions and approvals. The ultimate amount of Puget's ownership interest we acquire is contingent on a right-of-first-refusal held by other Colstrip owners which, if exercised prior to expiration in fourth quarter 2024, would reduce our acquired interest proportionately.

Acquisition of Puget’s entire ownership interest, in addition to the previously disclosed acquisition of Avista’s 15 percent interest in each of Colstrip Units 3 and 4 (collectively representing 222 megawatts), would result in our ownership of 55 percent of the facility with the ability to guide operating and maintenance investments. This provides capacity to help us meet our obligation to provide reliable and cost effective power to our customers in Montana, while allowing opportunity for us to identify and plan for newer lower or no-carbon technologies in the future.

Transmission Investment

In August 2024, the U.S. Department of Energy awarded a $700 million grant through the Grid Resilience and Innovation Partnership (GRIP) program to advance the North Plains Connector (NPC) Consortium project. The 415-mile, high-voltage direct-current transmission line is intended to connect Montana's Colstrip substation, of which we are the operator and a joint owner, to central North Dakota, bridging the eastern and western U.S. energy grids. The NPC Consortium includes potential upgrades to our jointly owned Colstrip Transmission System and $70 million of the award is earmarked for the Colstrip Transmission System Upgrade. The NPC project, estimated to be a $3.6 billion investment, aims to enhance grid reliability, support renewable energy integration, and provide additional capacity across multiple states. We collaborated with Grid United, the Montana Department of Commerce, and other regional utilities on the successful GRIP grant application. The project is a critical infrastructure investment that aligns with our commitment to providing reliable and affordable energy to our customers while also supporting broader grid resilience efforts in the region. In addition to the Colstrip Transmission System Upgrade, we are considering an investment in NPC and are engaged in regional transmission development activities.

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 5

CONDENSED CONSOLIDATED STATEMENT OF INCOME


(in millions)	Three Months Ended September 30,				Nine Months Ended September 30,
Reconciliation of gross margin to utility margin:	2024		2023		2024		2023

Operating Revenues	$	345.2	$	321.1	$	1,140.4	$	1,066.1
Less: Fuel, purchased supply and direct transmission expense (exclusive of depreciation and depletion shown separately below)	87.9		88.9		339.1		322.0
Less: Operating and maintenance	55.9		53.2		167.4		163.9
Less: Property and other taxes	41.6		43.3		125.0		132.6
Less: Depreciation and depletion	57.0		52.2		170.6		157.8
Gross Margin	102.8		83.5		338.3		289.8

Operating and maintenance	55.9		53.2		167.4		163.9
Property and other taxes	41.6		43.3		125.0		132.6
Depreciation and depletion	57.0		52.2		170.6		157.8
Utility Margin(1)	$	257.3	$	232.2	$	801.3	$	744.1
(1) Non-GAAP financial measure. See “Non-GAAP Financial Measures” below.


	Three Months Ended September 30,				Nine Months Ended September 30,
(in millions, except per share amounts)	2024		2023		2024		2023
Revenues	$	345.2	$	321.1	$	1,140.4	$	1,066.1
Fuel, purchased supply and direct transmission expense(1)	87.9		88.9		339.1		322.0
Utility Margin (2)	257.3		232.2		801.3		744.1

Operating and maintenance	55.9		53.2		167.4		163.9
Administrative and general	34.9		29.4		106.7		94.1
Property and other taxes	41.6		41.8		125.0		131.0
Depreciation and depletion	57.0		52.2		170.6		157.8
Total Operating Expenses (3)	189.4		176.6		569.7		546.8
Operating income	67.9		55.6		231.6		197.3
Interest expense, net	(33.4)		(28.7)		(96.3)		(85.1)
Other income, net	9.1		4.1		19.6		12.9
Income before income taxes	43.7		31.0		155.0		125.1
Income tax benefit (expense)	3.2		(1.7)		(11.4)		(14.1)
Net Income	46.8		29.3		143.6		111.0
Basic Shares Outstanding	61.3		60.4		61.3		60.0
Earnings per Share - Basic	$	0.76	$	0.48	$	2.34	$	1.85
Diluted Shares Outstanding	61.4		60.5		61.4		60.0
Earnings per Share - Diluted	$	0.76	$	0.48	$	2.34	$	1.85

Dividends Declared per Common Share	$	0.65	$	0.64	$	1.95	$	1.92
(1) Exclusive of depreciation and depletion expense. (2) Utility Margin is a Non-GAAP financial measure. See "Reconciliation of gross margin to utility margin" above and “Non-GAAP Financial Measures” below. (3) Excluding fuel, purchased supply and direct transmission expense. Note: Subtotal variances may exist due to rounding.

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 6

RECONCILIATION OF PRIMARY CHANGES DURING THE QUARTER


	Three Months Ended September 30, 2024 vs. 2023
	Pre-tax Income		Income Tax (Expense) Benefit (3)		Net Income		Diluted Earnings Per Share
	(in millions, except EPS)
Third Quarter, 2023	$	31.0	$	(1.7)	$	29.3	$	0.48
Variance in revenue and fuel, purchased supply, and direct transmission expense(1) items impacting net income:
Base rates	17.2		(4.4)		12.8		0.21
Electric transmission revenue	5.9		(1.5)		4.4		0.07
Electric retail volumes	3.6		(0.9)		2.7		0.04
Montana property tax tracker collections	1.5		(0.4)		1.1		0.02
Montana natural gas transportation	0.9		(0.2)		0.7		0.01
Non-recoverable Montana electric supply costs	0.6		(0.2)		0.4		0.01
Natural gas retail volumes	(0.3)		0.1		(0.2)		—
Production tax credits, offset within income tax benefit	(0.2)		0.2		—		—
Other	(1.2)		0.3		(0.9)		(0.01)

Variance in expense items(2) impacting net income:
Operating, maintenance, and administrative	(5.5)		1.4		(4.1)		(0.07)
Depreciation	(4.8)		1.2		(3.6)		(0.06)
Interest expense	(4.7)		1.2		(3.5)		(0.06)
Property and other taxes not recoverable within trackers	(1.9)		0.5		(1.4)		(0.02)
Gas repairs safe harbor method change	—		7.0		7.0		0.12
Other	1.5		0.6		2.1		0.03
Dilution from higher share count							(0.01)
Third Quarter, 2024	$	43.6	$	3.2	$	46.8	$	0.76
Change					$	17.5	$	0.28
(1) Exclusive of depreciation and depletion shown separately below (2) Excluding fuel, purchased supply, and direct transmission expense (3) Income Tax (Expense) Benefit calculation on reconciling items assumes blended federal plus state effective tax rate of 25.3%.

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NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 7

EXPLANATION OF CONSOLIDATED RESULTS

Three Months Ended September 30, 2024 Compared with the Three Months Ended September 30, 2023

Consolidated gross margin for the three months ended September 30, 2024 was $102.8 million as compared with $83.5 million in 2023, an increase of $19.3 million, or 23.1 percent. This increase was primarily due to new base rates in Montana and South Dakota, electric transmission revenues, electric retail volumes, Montana property tax tracker collections, and lower non-recoverable Montana electric supply costs. These were offset in part by natural gas retail volumes, depreciation, and operating and maintenance costs.


	Three Months Ended September 30,
(in millions)	2024		2023

Reconciliation of gross margin to utility margin:
Operating Revenues	$	345.2	$	321.1
Less: Fuel, purchased supply and direct transmission expense (exclusive of depreciation and depletion shown separately below)	87.9		88.9
Less: Operating and maintenance	55.9		53.2
Less: Property and other taxes	41.6		43.3
Less: Depreciation and depletion	57.0		52.2
Gross Margin	102.8		83.5

Operating and maintenance	55.9		53.2
Property and other taxes	41.6		43.3
Depreciation and depletion	57.0		52.2
Utility Margin(1)	$	257.3	$	232.2
(1) Non-GAAP financial measure. See “Non-GAAP Financial Measures” below.


	Three Months Ended September 30,
	2024		2023		Change		% Change
	(dollars in millions)
Utility Margin
Electric	$	225.7	$	202.0	$	23.7	11.7	%
Natural Gas	31.6		30.2		1.4		4.6
Total Utility Margin(1)	$	257.3	$	232.2	$	25.1	10.8	%
(1) Non-GAAP financial measure. See “Non-GAAP Financial Measures” below.

Consolidated utility margin for the three months ended September 30, 2024 was $257.3 million as compared with $232.2 million for the same period in 2023, an increase of $25.1 million, or 10.8 percent.

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 8

Primary components of the change in utility margin include the following (in millions):


	Utility Margin 2024 vs. 2023
Utility Margin Items Impacting Net Income
Base rates	$	17.2
Transmission revenue due to market conditions and rates	5.9
Electric retail volumes	3.6
Montana property tax tracker collections	1.5
Montana natural gas transportation	0.9
Non-recoverable Montana electric supply costs	0.6
Natural gas retail volumes	(0.3)
Other	(1.2)
Change in Utility Margin Items Impacting Net Income	28.2
Utility Margin Items Offset Within Net Income
Property and other taxes recovered in revenue, offset in property and other taxes	(2.0)
Operating expenses recovered in revenue, offset in operating and maintenance expense	(0.9)
Production tax credits, offset in income tax expense	(0.2)
Change in Utility Margin Items Offset Within Net Income	(3.1)
Increase in Consolidated Utility Margin(1)	$	25.1
(1) Non-GAAP financial measure. See “Non-GAAP Financial Measures” below.

Higher electric retail volumes were driven by favorable weather in Montana impacting residential demand, higher commercial and industrial demand, and customer growth in all jurisdictions, partly offset by unfavorable weather in South Dakota impacting residential demand. Lower natural gas retail volumes were driven by unfavorable weather in Montana partly offset by customer growth in all jurisdictions.

Under the PCCAM, net supply costs higher or lower than the PCCAM base rate (PCCAM Base) (excluding qualifying facility costs) are allocated 90 percent to Montana customers and 10 percent to shareholders. For the three months ended September 30, 2024, we over-collected supply costs of $5.9 million resulting in a reduction to our under collection of costs, and recorded an increase in pre-tax earnings of $0.7 million (10 percent of the PCCAM Base cost variance). For the three months ended September 30, 2023, we over-collected supply costs of $1.0 million resulting in a reduction to our under collection of costs, and recorded an increase in pre-tax earnings of $0.1 million.

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NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 9


	Three Months Ended September 30,
	2024		2023		Change		% Change
($ in millions)
Operating Expenses (excluding fuel, purchased supply and direct transmission expense)
Operating and maintenance	$	55.9	$	53.2	$	2.7	5.1	%
Administrative and general	34.9		29.4		5.5		18.7
Property and other taxes	41.6		41.8		(0.2)		(0.5)
Depreciation and depletion	57.0		52.2		4.8		9.2
Total Operating Expenses (excluding fuel, purchased supply and direct transmission expense)	$	189.4	$	176.6	$	12.8	7.2	%

Consolidated operating expenses, excluding fuel, purchased supply and direct transmission expense, were $189.4 million for the three months ended September 30, 2024, as compared with $176.6 million for the three months ended September 30, 2023. Primary components of the change include the following (in millions):


	Operating Expenses
	2024 vs. 2023
Operating Expenses (excluding fuel, purchased supply and direct transmission expense) Impacting Net Income
Depreciation expense due to plant additions and higher depreciation rates	$	4.8
Insurance expense, primarily due to increased wildfire risk premiums	3.4
Labor and benefits(1)	3.0
Electric generation maintenance	1.9
Property and other taxes not recoverable within trackers	1.9
Technology implementation and maintenance expenses	(0.1)
Partial recovery from previously impaired alternative energy storage investment	(0.5)
Uncollectible accounts	(1.1)
Other	(1.1)
Change in Items Impacting Net Income	12.2

Operating Expenses Offset Within Net Income
Property and other taxes recovered in trackers, offset in revenue	(2.0)
Operating and maintenance expenses recovered in trackers, offset in revenue	(0.9)
Deferred compensation, offset in other income	2.8
Pension and other postretirement benefits, offset in other income(1)	0.7
Change in Items Offset Within Net Income	0.6
Increase in Operating Expenses (excluding fuel, purchased supply and direct transmission expense)	$	12.8
(1) In order to present the total change in labor and benefits, we have included the change in the non-service cost component of our pension and other postretirement benefits, which is recorded within other income on our Condensed Consolidated Statements of Income. This change is offset within this table as it does not affect our operating expenses.

We estimate property taxes throughout each year, and update those estimates based on valuation reports received from the Montana Department of Revenue. Under Montana law, we are allowed to track the increases and decreases in the actual level of state and local taxes and fees and adjust our rates to recover the increase or decrease between rate cases less the amount allocated to Federal Energy Regulatory Commission-jurisdictional customers and net of the associated income tax benefit.

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 10

Consolidated operating income for the three months ended September 30, 2024 was $67.9 million as compared with $55.6 million in the same period of 2023. This increase was primarily due to new base rates in Montana and South Dakota, electric transmission revenues, electric retail volumes, Montana property tax tracker collections, and lower non-recoverable Montana electric supply costs. These were offset in part by natural gas retail volumes, depreciation, operating, and administrative and general expenses.

Consolidated interest expense was $33.4 million for the three months ended September 30, 2024 as compared with $28.7 million for the same period of 2023. This increase was due to higher borrowings and interest rates, partly offset by higher capitalization of Allowance for Funds Used During Construction (AFUDC).

Consolidated other income was $9.1 million for the three months ended September 30, 2024 as compared with $4.1 million for the same period of 2023. This increase was primarily due to higher capitalization of AFUDC, a decrease in the non-service component of pension expense, and an increase in the value of deferred shares held in trust for deferred compensation.

Consolidated income tax benefit was $3.2 million for the three months ended September 30, 2024 as compared to income tax expense of $1.7 million for the same period of 2023. Our effective tax rate for the three months ended September 30, 2024 was (7.3)% as compared with 5.5% for the same period in 2023. During the third quarter of 2024 we filed a tax accounting method change with the Internal Revenue Service consistent with the guidance for natural gas transmission and distribution property. This resulted in an income tax benefit of $7.0 million during the three months ended September 30, 2024, related to repair costs that were previously capitalized for tax purposes in the 2022 and prior tax years.

The following table summarizes the differences between our effective tax rate and the federal statutory rate ($ in millions):


	Three Months Ended September 30,
	2024				2023
Income Before Income Taxes	$	43.7			$	31.0

Income tax calculated at federal statutory rate	9.2		21.0	%	6.5		21.0	%

Permanent or flow-through adjustments:
State income tax, net of federal provisions	0.1		0.1		0.1		0.4
Gas repairs safe harbor method change	(7.0)		(16.0)		—		—
Flow-through repairs deductions	(4.6)		(10.5)		(4.2)		(13.5)
Production tax credits	(2.4)		(5.6)		(1.3)		(4.1)
Amortization of excess deferred income tax	(0.2)		(0.5)		(0.3)		(1.0)
Income tax return to accrual adjustment	—		—		0.4		1.3
Plant and depreciation flow-through items	1.8		4.2		0.4		1.2
Other, net	(0.1)		—		0.1		0.2
	(12.4)		(28.3)		(4.8)		(15.5)

Income tax (benefit) expense	$	(3.2)	(7.3)	%	$	1.7	5.5	%

We compute income tax expense for each quarter based on the estimated annual effective tax rate for the year, adjusted for certain discrete items. Our effective tax rate typically differs from the federal statutory tax rate primarily due to the regulatory impact of flowing through federal and state tax benefits of repairs deductions, state

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 11

tax benefit of accelerated tax depreciation deductions (including bonus depreciation when applicable) and production tax credits.

Consolidated net income for the three months ended September 30, 2024 was $46.8 million as compared with $29.3 million for the same period in 2023. This increase was primarily due to new base rates in Montana and South Dakota, electric transmission revenues, electric retail volumes, Montana property tax tracker collections, lower non-recoverable Montana electric supply costs, and an income tax benefit from a change to the gas repairs safe harbor method. These were offset in part by natural gas retail volumes, depreciation, operating, administrative and general costs, and interest expense.

LIQUIDITY AND OTHER CONSIDERATIONS

Liquidity and Capital Resources

As of September 30, 2024, our total net liquidity was approximately $316.5 million, including $2.5 million of cash and $314.0 million of revolving credit facility availability with no letters of credit outstanding. This compares to total net liquidity one year ago at September 30, 2023 of $378.1 million.

Earnings Per Share

Basic earnings per share are computed by dividing earnings applicable to common stock by the weighted average number of common shares outstanding for the period. Diluted earnings per share reflect the potential dilution of common stock equivalent shares that could occur if unvested shares were to vest. Common stock equivalent shares are calculated using the treasury stock method, as applicable. The dilutive effect is computed by dividing earnings applicable to common stock by the weighted average number of common shares outstanding plus the effect of the outstanding unvested restricted stock and performance share awards. Average shares used in computing the basic and diluted earnings per share are as follows:


	Three Months Ended
	September 30, 2024	September 30, 2023
Basic computation	61,301,696	60,442,164
Dilutive effect of:
Performance share awards(1)	95,279	35,533
Diluted computation	61,396,975	60,477,697


	Nine Months Ended
	September 30, 2024	September 30, 2023
Basic computation	61,285,570	60,010,609
Dilutive effect of:
Performance share awards(1)	69,136	31,311
Diluted computation	61,354,706	60,041,920
(1) Performance share awards are included in diluted weighted average number of shares outstanding based upon what would be issued if the end of the most recent reporting period was the end of the term of the award.

As of September 30, 2024, there were 16,015 shares from performance and restricted share awards which were antidilutive and excluded from the earnings per share calculations, compared to 32,649 shares as of September 30, 2023.

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 12

Adjusted Non-GAAP Earnings

We reported GAAP earnings of $0.76 per diluted share for the three months-ended September 30, 2024 and $0.48 per diluted share for the same period in 2023. Adjusted Non-GAAP earnings per diluted share for the same periods are $0.65 and $0.49, respectively. A reconciliation of items factored into our Adjusted Non-GAAP diluted earnings are summarized below. The amount below represents a non-GAAP measure that may provide users of this data with additional meaningful information regarding the impact of certain items on our expected earnings. More information on this measure can be found in the "Non-GAAP Financial Measures" section below.


(in millions, except EPS)

Three Months Ended September 30, 2024
	Pre-tax Income	Net(1) Income	Diluted EPS
2024 Reported GAAP	$43.7	$46.8	$	0.76

Non-GAAP Adjustments:
Unfavorable weather as compared to normal	0.4	0.3	0.01
Partial recovery from a previously impaired alternative energy storage investment	(0.5)	(0.4)	(0.01)
Natural gas repairs safe harbor method change	—	(7.0)	(0.11)

2024 Adj. Non-GAAP	$43.6	$39.7	$0.65


Three Months Ended September 30, 2023
	Pre-tax Income	Net(1) Income	Diluted EPS
2023 Reported GAAP	$31.0	$29.3	$	0.48

Non-GAAP Adjustments:
Unfavorable weather as compared to normal	0.9	0.7	0.01

2023 Adj. Non-GAAP	$31.9	$30.0	$0.49

(1) Income tax rate on reconciling items assumes blended federal plus state effective tax rate of 25.3%.

Company Hosting Earnings Webcast

NorthWestern will also host an investor earnings webcast on Wednesday, October 30, 2024, at 3:00 p.m. Eastern time to review its financial results for the quarter ending September 30, 2024. To register for the webcast, please visit www.northwesternenergy.com/earnings-registration. After registration, a link to access the event will be emailed to the address provided. Please note that a unique and valid email address is required for each attendee to access the webinar. Please go to the site at least 10 minutes in advance of the webinar to register. An archived webcast will be available shortly after the event and remain active for one year.

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 13

NorthWestern Energy - DELIVERING A BRIGHT FUTURE

NorthWestern Energy Group, Inc., doing business as NorthWestern Energy, provides essential energy infrastructure and valuable services that enrich lives and empower communities while serving as long-term partners to our customers and communities. We work to deliver safe, reliable, and innovative energy solutions that create value for customers, communities, employees, and investors. We do this by providing low-cost and reliable service performed by highly-adaptable and skilled employees. We provide electricity and / or natural gas to approximately 775,300 customers in Montana, South Dakota, Nebraska, and Yellowstone National Park. Our operations in Montana and Yellowstone National Park are conducted through our subsidiary, NorthWestern Corporation, and our operations in South Dakota and Nebraska are conducted through our subsidiary, NorthWestern Energy Public Service Company. We have provided service in South Dakota and Nebraska since 1923 and in Montana since 2002.

Non-GAAP Financial Measures

This press release includes financial information prepared in accordance with GAAP, as well as other financial measures, such as Utility Margin, Adjusted Non-GAAP pretax income, Adjusted Non-GAAP net income and Adjusted Non-GAAP Diluted EPS that are considered “non-GAAP financial measures.” Generally, a non-GAAP financial measure is 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.

We define Utility Margin as Operating Revenues less fuel, purchased supply and direct transmission expense (exclusive of depreciation and depletion) as presented in our Condensed Consolidated Statements of Income. This measure differs from the GAAP definition of Gross Margin due to the exclusion of Operating and maintenance, Property and other taxes, and Depreciation and depletion expenses, which are presented separately in our Condensed Consolidated Statements of Income. A reconciliation of Utility Margin to Gross Margin, the most directly comparable GAAP measure, is included in the press release above.

Management believes that Utility Margin provides a useful measure for investors and other financial statement users to analyze our financial performance in that it excludes the effect on total revenues caused by volatility in energy costs and associated regulatory mechanisms. This information is intended to enhance an investor's overall understanding of results. Under our various state regulatory mechanisms, as detailed below, our supply costs are generally collected from customers. In addition, Utility Margin is used by us to determine whether we are collecting the appropriate amount of energy costs from customers to allow for recovery of operating costs, as well as to analyze how changes in loads (due to weather, economic or other conditions), rates and other factors impact our results of operations. Our Utility Margin measure may not be comparable to that of other companies' presentations or more useful than the GAAP information provided elsewhere in this report.

Management also believes the presentation of Adjusted Non-GAAP pre-tax income, Adjusted Non-GAAP net income and Adjusted Non-GAAP Diluted EPS is more representative of normal earnings than GAAP pre-tax income, net income and EPS due to the exclusion (or inclusion) of certain impacts that are not reflective of ongoing earnings. The presentation of these non-GAAP measures is intended to supplement investors' understanding of our financial performance and not to replace other GAAP measures as an indicator of actual operating performance. Our measures may not be comparable to other companies' similarly titled measures.

Special Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, including, without limitation, the information under "Reconciliation of Non-GAAP Items." Forward-looking statements involve risks and uncertainties, which could

NorthWestern Reports Third Quarter 2024 Financial Results

October 28, 2024

Page 14

cause actual results or outcomes to differ materially from those expressed. We caution that while we make such statements in good faith and believe such statements are based on reasonable assumptions, including without limitation, management's examination of historical operating trends, data contained in records and other data available from third parties, we cannot assure you that we will achieve our projections. Factors that may cause such differences include, but are not limited to:

•adverse determinations by regulators, as well as potential adverse federal, state, or local legislation or regulation, including costs of compliance with existing and future environmental requirements, and wildfire damages in excess of liability insurance coverage, could have a material effect on our liquidity, results of operations and financial condition;

•the impact of extraordinary external events and natural disasters, such as a wide-spread or global pandemic, geopolitical events, earthquake, flood, drought, lightning, weather, wind, and fire, could have a material effect on our liquidity, results of operations and financial condition;

•acts of terrorism, cybersecurity attacks, data security breaches, or other malicious acts that cause damage to our generation, transmission, or distribution facilities, information technology systems, or result in the release of confidential customer, employee, or Company information;

•supply chain constraints, recent high levels of inflation for product, services and labor costs, and their impact on capital expenditures, operating activities, and/or our ability to safely and reliably serve our customers;

•changes in availability of trade credit, creditworthiness of counterparties, usage, commodity prices, fuel supply costs or availability due to higher demand, shortages, weather conditions, transportation problems or other developments, may reduce revenues or may increase operating costs, each of which could adversely affect our liquidity and results of operations;

•unscheduled generation outages or forced reductions in output, maintenance or repairs, which may reduce revenues and increase operating costs or may require additional capital expenditures or other increased operating costs; and

•adverse changes in general economic and competitive conditions in the U.S. financial markets and in our service territories.

Our 2023 Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, reports on Form 8-K and other Securities and Exchange Commission filings discuss some of the important risk factors that may affect our business, results of operations and financial condition. We undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Investor Relations Contact: Media Contact:

Travis Meyer (605) 978-2967 Jo Dee Black (866) 622-8081

travis.meyer@northwestern.com jodee.black@northwestern.com

2024 Third Quarter Earnings Webcast October 30, 2024 18-K October 30, 2024

NorthWestern Energy 2 Forward Looking Statements During the course of this presentation, there will be forward- looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements often address our expected future business and financial performance, and often contain words such as “expects,” “anticipates,” “intends,” “plans,” “believes,” “seeks,” or “will.” The information in this presentation is based upon our current expectations as of the date of this document unless otherwise noted. Our actual future business and financial performance may differ materially and adversely from our expectations expressed in any forward-looking statements. We undertake no obligation to revise or publicly update our forward-looking statements or this presentation for any reason. Although our expectations and beliefs are based on reasonable assumptions, actual results may differ materially. The factors that may affect our results are listed in certain of our press releases and disclosed in the Company’s 10-K and 10-Q along with other public filings with the SEC.

Recent Highlights • Reported GAAP diluted EPS of $0.76 o Non-GAAP diluted EPS of $0.651 • Revising 2024 non-GAAP EPS guidance to $3.32 - $3.47 in light of delay in Montana interim rates • Reaffirming long-term (5 year) rate base and earnings per share growth rates targets of 4% - 6%2 • Dividend Declared: $0.65 per share payable December 31, 2024 to shareholders of record as of December 13, 2024 • Yellowstone County Generating Station began serving customers in October • In August 2024, U.S. DOE awarded $700M Grid Resilience and Innovation Partnership (GRIP) Grant to North Plains Connector Consortium project, including $70M earmarked for Colstrip Transmission System upgrades 1.) See “Third Quarter 2024 Non-GAAP Earnings” below and “Non-GAAP Financial Measures” in appendix 2.) Based on 2022 adjusted non-GAAP earnings of $3.18 per diluted share and 2022 estimated rate base of $4.54 billion 3

9%-11% Total Growth 11%+ Total Growth Incremental Opportunities: 6% + EPS Growth ~5% Dividend Yield Base Capital Plan: 4%-6% EPS Growth  FERC Transmission  Incremental generating capacity (subject to successful resource procurement bids)  Qualifying Facility and / or Power Purchase Agreement buyouts  Electrification supporting economic development Nearly $2.5 billion of highly executable and low-risk capital investment forecasted over the next five years. This investment is expected to drive annualized earnings and rate base growth of approximately 4% - 6%. See slide titled “Strong Growth Outlook” for additional information. + The NorthWestern Value Proposition + 4 = =

Thank youQ3 Financial Results 5

Third Quarter Financial Results 6 1.) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. Note: Subtotal variances may exist due to rounding.

Third Quarter 2024 Financial Results 7 1.) See “Third Quarter 2024 Non-GAAP Earnings” below and “Non-GAAP Financial Measures” in appendix. Third Quarter Net Income vs Prior Period •GAAP: 17.5 million or 59.7% •Non-GAAP1: 9.7 million or 32.4% Third Quarter EPS vs Prior Period •GAAP: $0.28 or 58.3% •Non-GAAP1: $0.16 or 32.7%

Year-to-Date 2024 Financial Results 8 Year-to-Date Net Income vs Prior Period •GAAP: 32.6 million or 29.4% •Non-GAAP1: 25.6 million or 22.6% Year-to-Date EPS vs Prior Period •GAAP: $0.49 or 26.5% •Non-GAAP1: $0.38 or 20.1% 1.) See “Third Quarter 2024 Non-GAAP Earnings” below and “Non-GAAP Financial Measures” in appendix.

Third Quarter Earnings Drivers 9 2 Increase in diluted EPS primarily due to rate relief, transmission revenues, and a tax benefit, offset by higher operating and interest expense. 1.) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. 2.) See “Third Quarter 2024 Non-GAAP Earnings” below and “Non-GAAP Financial Measures” in appendix. After-tax EPS vs Prior Year

Third Quarter Utility Margin Bridge Pre-tax Millions vs. Prior Year $28.2 million or 12.1% increase in Utility Margin items that impact Net Income NOTE: Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. 10

We estimate weather to be a $0.4 million pre-tax detriment as compared to normal and a $0.5 million benefit as compared to third quarter 2023. (1) As a result of the adoption of Accounting Standard Update 2017-07 in March 2018, pension and other employee benefit expense is now disaggregated on the GAAP income statement with portions now recorded in both OG&A expense and Other (Expense) Income lines. To facilitate better understanding of trends in year-over-year comparisons, the non-GAAP adjustment above re-aggregates the expense in OG&A - as it was historically presented prior to the ASU 2017-07 (with no impact to net income or earnings per share). (2) Utility Margin is a non-GAAP Measure. See the slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosures. Third Quarter 2024 Non-GAAP Earnings 11 Note: Subtotal variances may exist due to rounding.

Credit, Cash Flow, and Financing Plans 12 Credit Ratings 2024 Financing Plan No equity expected to fund the current 5-year | $2.5 billion capital plan Financing plans (targeting a FFO to Debt ratio > 14%) are expected to maintain our current credit ratings. We expect to pay minimal cash taxes into 2028 due to utilization of our NOL’s and tax credits. Financing plans are subject to change.

Strong Growth Outlook  Revised 2024 Non-GAAP EPS Guidance1 of $3.32 - $3.47 • Assumes normal weather, Montana interim rates starting in December, an effective tax rate of 9% to 11%, and diluted shares outstanding of 61.4 million.  Affirming long-term (5 Year) expected growth rates • EPS growth of 4% to 6% from 2022 base year of $3.18 Non-GAAP • Rate base growth of 4% to 6% from 2022 base year $4.54 billion • Continued focus on earned returns driven by financial and operational execution  No equity expected to fund the current 5-year | $2.5 billion capital plan • Capital plan is expected to be funded by cash from operations (aided by net operating losses1) and secured debt • Any equity needs would be driven by incremental opportunities  Expect to maintain FFO / Debt > 14% through 2024 and beyond  Earnings growth is expected to exceed dividend growth until we return to our targeted 60% to 70% payout ratio. 13 1.) See “2024 Earnings Bridge” in the Appendix for additional detail.

Thank youRate Reviews 14

15 Rate Review Summary Key Dates of Montana procedural Schedule • 12/20/24: Final day for data requests to NWE (with final responses due 1/10/25) • 1/17/25: Intervenor testimony due • 3/14/25: NWE rebuttal and cross- intervenor testimony due • 3/24/25: Final day to file settlements • 4/22/25: Hearing Commences

Conclusion Pure Electric & Gas Utility Solid Utility Foundation Best Practices Corporate Governance Attractive Future Growth Prospects Strong Earnings & Cash Flows 16 NorthWestern Energy Group, Inc. dba: NorthWestern Energy Ticker: NWE (Nasdaq) www.northwesternenergy.com Corporate Support Office 3010 West 69th Street Sioux Falls, SD 57108 (605) 978-2900 Investor Relations Officer Travis Meyer 605-978-2967 travis.meyer@northwestern.com

Thank youAppendix: 17

2024 Earnings Bridge Revising 2024 Non-GAAP EPS guidance in light of delay in Montana interim rates This guidance range is based upon, but not limited to, the following major assumptions: • Normal weather in our service territories; • Interim rates in Montana in December 2024 • An effective income tax rate of approximately 9%- 11%; and • Diluted average shares outstanding of approximately 61.4 million. 18 Appendix

$2.5 billion of highly-executable and low-risk capital investment Regulated Utility Five-Year Capital Forecast 19 Appendix

(1) The revenue requirement associated with the FERC regulated portion of Montana electric transmission and ancillary services are included as revenue credits to our MPSC jurisdictional customers. Therefore, we do not separately reflect FERC authorized rate base or authorized returns. (2) The Montana gas revenue requirement includes a step down which approximates annual depletion of our natural gas production assets included in rate base. (3) For those items marked as "n/a," the respective settlement and/or order was not specific as to these terms. (4) On June 15, 2023, we filed a South Dakota electric rate review filing (2022 test year) with the South Dakota Public Utility Commission Coal Generation Rate Base as a percentage of Total Rate Base Revenue from coal generation is not easily identifiable due to the use of bundled rates in South Dakota and other rate design and accounting considerations. However, NorthWestern is a fully regulated utility company for which rate base is the primary driver for earnings. The data to the left illustrates that NorthWestern only derives approximately 9 -14% of earnings from its jointly owned coal generation rate base. Rate Base & Authorized Return Summary Appendix 20

Thank youThird Quarter Appendix 21

Utility Margin (Q3) (dollars in millions) Three Months Ended September 30, 2024 2023 Variance Electric $ 225.7 $ 202.0 $ 23.7 11.7% Natural Gas 31.6 30.2 1.4 4.6% Total Utility Margin1 $ 257.3 $ 232.2 $ 25.1 10.8% (1) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. Increase in utility margin due to the following factors: $ 17.2 Base rates 5.9 Transmission revenue due to market conditions and rates 3.6 Electric retail volumes 1.5 Montana property tax tracker collections 0.9 Montana natural gas transportation 0.6 Non-recoverable Montana electric supply costs (0.3) Natural gas retail volumes (1.2) Other $ 28.2 Change in Utility Margin Impacting Net Income $ (2.0) Property & other taxes recovered in revenue, offset in property & other taxes (0.9) Operating expenses recovered in revenue, offset in operating & maintenance expense (0.2) Production tax credits, offset in income tax expense $ (3.1) Change in Utility Margin Offset Within Net Income $ 25.1 Increase in Utility Margin 22 Appendix

Operating Expenses (Q3) Increase in operating expenses due to the following factors: $ 4.8 Depreciation expense due to plant additions and higher depreciation rates 3.4 Insurance expense, primarily due to increased wildfire risk premiums 3.0 Labor and benefits(1) 1.9 Electric generation maintenance 1.9 Property and other taxes not recoverable within trackers (0.1) Technology implementation and maintenance expenses (0.5) Partial recovery from previously impaired alternative energy storage investment (1.1) Uncollectible accounts (1.1) Other $ 12.2 Change in Operating Expense Items Impacting Net Income (dollars in millions) Three Months Ended September 30, 2024 2023 Variance Operating & maintenance $ 55.9 $ 53.2 $ 2.7 5.1% Administrative & general 34.9 29.4 5.5 18.7% Property and other taxes 41.6 41.8 (0.2) (0.5)% Depreciation and depletion 57.0 52.2 4.8 9.2% Operating Expenses $ 189.4 $ 176.6 $ 12.8 7.2% $ (2.0) Property and other taxes recovered in trackers, offset in revenue (0.9) Operating and maintenance expenses recovered in trackers, offset in revenue 2.8 Deferred compensation, offset in other income 0.7 Pension and other postretirement benefits, offset in other income(1) $ 0.6 Change in Operating Expense Items Offset Within Net Income $ 12.8 Increase in Operating Expenses (1) In order to present the total change in labor and benefits, we have included the change in the non- service cost component of our pension and other postretirement benefits, which is recorded within other income on our Condensed Consolidated Statements of Income. This change is offset within this table as it does not affect our operating expenses. 23 Appendix

Operating to Net Income (Q3) (dollars in millions) Three Months Ended September 30, 2024 2023 Variance Operating Income $ 67.9 $ 55.6 $ 12.3 22.1% Interest expense (33.4) (28.7) (4.7) (16.4)% Other income, net 9.1 4.1 5.0 122.0% Income Before Taxes 43.7 31.0 12.7 41.0% Income tax benefit (expense) 3.2 (1.7) 4.9 288.2% Net Income $ 46.8 $ 29.3 $ 17.5 59.7% $4.7 million increase in interest expense was primarily due to higher borrowings and interest rates, partly offset by higher capitalization of Allowance for Funds Used During Construction (AFUDC). $5.0 million increase in other income, net was primarily due to higher capitalization of AFUDC, a decrease in the non-service component of pension expense, and an increase in the value of deferred shares held in trust for deferred compensation. $4.9 million increase in income tax benefit was primarily due to a natural gas safe harbor tax repairs accounting method change offset by higher pre-tax income. 24 Appendix

Tax Reconciliation (Q3) 25 Appendix (in millions) Variance Income Before Income Taxes $43.7 $31.0 12.7 Income tax calculated at federal statutory rate 9.2 21.0% 6.5 21.0% 2.7 Permanent or flow-through adjustments: State income tax, net of federal provisions 0.1 0.1% 0.1 0.4% - Gas repairs safe harbor method change (7.0) (16.0%) - - (7.0) Flow-through repairs deductions (4.6) (10.5%) (4.2) (13.5%) (0.4) Production tax credits (2.4) (5.6%) (1.3) (4.1%) (1.1) Amortization of excess deferred income tax (0.2) (0.5%) (0.3) (1.0%) 0.1 Income tax return to accrual adjustment - - 0.4 1.3% (0.4) Plant and depreciation flow-through items 1.8 4.2% 0.4 1.2% 1.4 Other, net (0.1) - 0.1 0.2% (0.2) Sub-total (12.4) (28.3%) (4.8) (15.5%) (7.6) Income Tax (Benefit) Expense (3.2)$ (7.3%) 1.7$ 5.5% (4.9)$ Three Months Ended September 30, 2024 2023

Segment Results (Q3) (1) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. 26 Appendix Three Months Ended September 30, 2024 Electric Gas Other Total Operating revenues 306,478$ 38,683$ -$ 345,161$ Fuel, purchased supply & direct transmission* 80,761 7,127 - 87,888 Utility margin 225,717 31,556 - 257,273 Operating and maintenance 42,491 13,375 - 55,866 Administrative and general 24,892 9,887 145 34,924 Property and other taxes 32,251 9,345 - 41,596 Depreciation & depletion 47,540 9,414 - 56,954 Operating income (loss) 78,543 (10,465) (145) 67,933 Interest expense (24,188) (7,537) (1,672) (33,397) Other income 6,057 3,017 42 9,116 Income tax (expense) benefit (7,635) 9,734 1,068 3,167 Net income (loss) 52,777$ (5,251)$ (707)$ 46,819$ Three Months Ended September 30, 2023 Electric Gas Other Total Operating revenues 280,030$ 41,060$ -$ 321,090$ Fuel, purchased supply & direct transmission* 77,995 10,948 - 88,943 Utility margin 202,035 30,112 - 232,147 Operating and maintenance 39,990 13,250 - 53,240 Administrative and general 20,682 8,249 424 29,355 Property and other taxes 33,740 9,574 (1,551) 41,763 Depreciation & depletion 43,230 8,929 - 52,159 Operating income (loss) 64,393 (9,890) 1,127 55,630 Interest expense (21,300) (4,426) (2,999) (28,725) Other income (expense) 3,380 1,328 (581) 4,127 Income tax (expense) benefit (3,223) (41) 1,567 (1,697) Net income (loss) 43,250$ (13,029)$ (886)$ 29,335$ * Direct Transmission expense excludes depreciation and depletion (in thousands) 1 1

2024 2023 $ % 2024 2023 2024 2023 Montana 100,737$ 96,812$ 3,925$ 4.1 % 685 664 328,962 322,832 South Dakota 19,062 17,951 1,111 6.2 % 145 151 51,393 51,236 Residential 119,799 114,763 5,036 4.4 % 830 815 380,355 374,068 Montana 109,655 110,100 (445) (0.4) % 830 825 75,857 74,385 South Dakota 30,053 27,474 2,579 9.4 % 288 289 13,115 12,989 Commercial 139,708 137,574 2,134 1.6 % 1,118 1,114 88,972 87,374 Industrial 11,852 11,423 429 3.8 % 726 691 80 79 Other 14,071 13,243 828 6.3 % 82 71 8,274 8,204 Total Retail Electric 285,430 277,003 8,427 3.0 % 2,756 2,691 477,681 469,725 Regulatory amortization (6,805) (18,534) 11,729 (63.3) % Transmission 25,750 19,847 5,903 29.7 % Wholesale and other 2,103 1,714 389 22.7 % Total Revenues 306,478 280,030 26,448 9.4 % Total fuel, purchased supply & direct transmission expense* 80,761 77,995 2,766 3.5 % Utility Margin 225,717 202,035 23,682 11.7 % * Direct transmission expense is exclusive of depreciation and depletion expense (in thousands) Megawatt Hours (MWH) Average Customer CountsChange Three Months Ended September 30, Revenues 1 Electric Segment (Q3) (1) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. 27 Appendix

2024 2023 $ % 2024 2023 2024 2023 Montana 8,422$ 9,603$ (1,181)$ (12.3) % 739 825 185,578 183,586 South Dakota 1,745 1,987 (242) (12.2) % 108 102 42,389 41,821 Nebraska 1,791 2,251 (460) (20.4) % 143 138 37,834 37,580 Residential 11,958 13,841 (1,883) (13.6) % 990 1,065 265,801 262,987 Montana 6,190 6,136 54 0.9 % 609 622 26,094 25,657 South Dakota 1,262 1,498 (236) (15.8) % 225 208 7,336 7,184 Nebraska 795 1,291 (496) (38.4) % 134 142 5,009 4,970 Commercial 8,247 8,925 (678) (7.6) % 968 972 38,439 37,811 Industrial 115 106 9 8.5 % 15 13 238 231 Other 169 160 9 5.6 % 23 19 196 191 Total Retail Electric 20,489$ 23,032$ (2,543)$ (11.0) % 1,996 2,069 304,674 301,220 Regulatory amortization 8,025 7,458 567 (7.6) % Wholesale and other 10,169 10,570 (401) (3.8) % Total Revenues 38,683$ 41,060$ (2,377)$ (5.8) % Total fuel, purchased supply & direct transmission expense* 7,127$ 10,948$ (3,821)$ (34.9) % Utility Margin 31,556$ 30,112$ 1,444$ 4.8 % - * Direct transmission expense is exclusive of depreciation and depletion expense Revenues Dekatherms (Dkt) Average Customer CountsChange Three Months Ended September 30, (in thousands) 1 Natural Gas Segment (Q3) 28 Appendix (1) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure.

Thank you2024 Year-to-Date Appendix 29

Year-to-Date Financial Results 30 1.) Utility Margin is a non- GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. Note: Subtotal variances may exist due to rounding. Appendix

(1) As a result of the adoption of Accounting Standard Update 2017-07 in March 2018, pension and other employee benefit expense is now disaggregated on the GAAP income statement with portions now recorded in both OG&A expense and Other (Expense) Income lines. To facilitate better understanding of trends in year-over-year comparisons, the non-GAAP adjustment above re- aggregates the expense in OG&A - as it was historically presented prior to the ASU 2017-07 (with no impact to net income or earnings per share). (2) Utility Margin is a non-GAAP Measure. See the slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. Year-to-Date 2024 Non-GAAP Earnings 31 For the nine months ended September 30, we estimate weather to be a $2.3 million pre-tax detriment as compared to normal and a $3.2 million detriment as compared to 2023. The adjusted non-GAAP measures presented in the table reflect significant items that are non-recurring or a variance from normal weather, however they should not be considered a substitute for financial results and measures determined or calculated in accordance with GAAP. Appendix Note: Subtotal variances may exist due to rounding.

Utility Margin (YTD) (dollars in millions) Nine Months Ended September 30, 2024 2023 Variance Electric $ 652.8 $ 606.1 $ 46.7 7.7% Natural Gas 148.5 138.0 10.5 7.6% Total Utility Margin(1) $ 801.3 $ 744.1 $ 57.2 7.7% Increase in utility margin due to the following factors: $ 53.4 Base rates 13.5 Transmission revenue due to market conditions and rates 4.9 Montana property tax tracker collections(2) 1.9 Montana natural gas transportation 1.0 Electric retail volumes (4.2) QF liability adjustment (3.8) Non-recoverable Montana electric supply costs (2.7) Natural gas retail volumes 2.4 Other $ 66.4 Change in Utility Margin Impacting Net Income $ (8.2) Property & other taxes recovered in revenue, offset in property & other taxes (1.5) Production tax credits, offset in income tax expense 0.5 Operating expenses recovered in revenue, offset in operating & maintenance expense $ (9.2) Change in Utility Margin Offset Within Net Income $ 57.2 Increase in Utility Margin 32 Appendix (1) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. (2) In the fourth quarter of 2023, upon receiving the final valuation reports from the Montana Department of Revenue, we recorded a significant reduction in property tax expense. Accordingly, we do not anticipate this year-to-date favorable change to Utility Margin to continue on a full year basis.

(dollars in millions) Nine Months Ended September 30, 2024 2023 Variance Operating & maintenance $ 167.4 $ 163.9 $ 3.5 2.1% Administrative & general 106.7 94.1 12.6 13.4% Property and other taxes 125.0 131.0 (6.0) (4.6)% Depreciation and depletion 170.6 157.8 12.8 8.1% Operating Expenses $ 569.7 $ 546.8 $ 22.9 4.2% Increase in operating expenses due to the following factors: $ 12.8 Depreciation expense due to plant additions and higher depreciation rates 6.4 Labor and benefits(1) 4.4 Insurance expense, primarily due to increased wildfire risk premiums 2.4 Litigation outcome (Pacific Northwest Solar) 2.2 Property and other taxes not recoverable within trackers 1.7 Non-cash impairment of alternative energy storage investment 1.3 Electric generation maintenance 0.5 Technology implementation and maintenance expenses (2.1) Uncollectible accounts (2.4) Other $ 27.2 Change in Operating Expense Items Impacting Net Income $ (8.2) Property and other taxes recovered in trackers, offset in revenue 2.9 Deferred compensation, offset in other income 0.5 Pension and other postretirement benefits, offset in other income(1) 0.5 Operating and maintenance expenses recovered in trackers, offset in revenue $ (4.3) Change in Operating Expense Items Offset Within Net Income $ 22.9 Increase in Operating Expenses Operating Expenses (YTD) (1) In order to present the total change in labor and benefits, we have included the change in the non- service cost component of our pension and other postretirement benefits, which is recorded within other income on our Condensed Consolidated Statements of Income. This change is offset within this table as it does not affect our operating expenses. 33 Appendix

Operating to Net Income (YTD) (dollars in millions) Nine Months Ended September 30, 2024 2023 Variance Operating Income $ 231.6 $ 197.3 $ 34.3 17.4% Interest expense (96.3) (85.1) (11.2) (13.2)% Other income, net 19.6 12.9 6.7 51.9% Income Before Taxes 155.0 125.1 29.9 23.9% Income tax expense (11.4) (14.1) 2.7 (19.1)% Net Income $ 143.6 $ 111.0 $ 32.6 29.4% $11.2 million increase in interest expense was primarily due to higher borrowings and interest rates partly offset by higher capitalization of AFUDC. $6.7 million increase in other income, net was primarily due a $2.3 million reversal of a previously expensed Community Renewable Energy Project penalty due to a favorable legal ruling, higher capitalization of AFUDC, a decrease in the non-service component of pension expense, and an increase in the value of deferred shares held in trust for deferred compensation, partly offset by a $2.5 million non-cash impairment of an alternative energy storage equity investment. $2.7 million decrease in income tax expense was primarily due to a natural gas safe harbor tax repairs accounting method change and other increased flow-through benefits offset by higher pre- tax income. 34 Appendix

Tax Reconciliation (YTD) 35 Appendix Variance Income Before Income Taxes $155.0 $125.1 $29.9 Income tax calculated at federal statutory rate 32.5 21.0% 26.3 21.0% 6.2 Permanent or flow-through adjustments: State income taxes, net of federal provisions 0.7 0.5% 1.4 1.1% (0.7) Flow-through repairs deductions (13.8) (8.9%) (11.7) (9.4%) (2.1) Production tax credits (7.4) (4.8%) (5.6) (4.5%) (1.8) Gas repairs safe harbor method change (7.0) (4.5%) - - (7.0) Amortization of excess deferred income tax (0.8) (0.5%) (1.4) (1.1%) 0.6 Reduction to previously claimed alternative minimum tax credit - - 3.2 2.5% (3.2) Income tax return to accrual adjustment - - 0.4 0.3% (0.4) Plant and depreciation flow-through items 6.0 3.8% 1.2 1.0% 4.8 Share-based compensation 0.3 0.2% 0.4 0.3% (0.1) Other, net 0.9 0.6% (0.1) 0.1% 1.0 Sub-total (21.1) (13.6%) (12.2) (9.7%) (8.9) Income Tax Expense 11.4$ 7.4% 14.1$ 11.3% (2.7)$ 2024 2023 Nine Months Ended September 30,

Segment Results (YTD) (1) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. 36 Appendix Nine Months Ended September 30, 2024 Electric Gas Other Total Operating revenues 909,798$ 230,634$ -$ 1,140,432$ Fuel, purchased supply & direct transmission* 256,989 82,100 - 339,089 Utility margin 652,809 148,534 - 801,343 Operating and maintenance 126,257 41,158 - 167,415 Administrative and general 76,105 27,754 2,791 106,650 Property and other taxes 96,557 28,465 1 125,023 Depreciation & depletion 142,390 28,240 - 170,630 Operating income (loss) 211,500 22,917 (2,792) 231,625 Interest expense (72,143) (20,933) (3,175) (96,251) Other income (expense) 15,549 4,998 (952) 19,595 Income tax (expense) benefit (18,809) 6,865 534 (11,410) Net income (loss) 136,097$ 13,847$ (6,385)$ 143,559$ Nine Months Ended September 30, 2023 Electric Gas Other Total Operating revenues 804,604$ 261,530$ -$ 1,066,134$ Fuel, purchased supply & direct transmission* 198,492 123,521 - 322,013 Utility margin 606,112 138,009 - 744,121 Operating and maintenance 123,771 40,170 - 163,941 Administrative and general 67,285 26,336 437 94,058 Property and other taxes 103,013 29,576 (1,546) 131,043 Depreciation & depletion 130,447 27,340 - 157,787 Operating Income (loss) 181,596 14,587 1,109 197,292 Interest expense (61,584) (12,167) (11,393) (85,144) Other income (expense) 9,700 3,887 (661) 12,926 Income tax expense (13,366) (180) (539) (14,085) Net income (loss) 116,346$ 6,127$ (11,484)$ 110,989$ * Direct Transmission expense excludes depreciation and depletion (in thousands) 1 1

2024 2023 $ % 2024 2023 2024 2023 Montana 304,128$ 306,114$ (1,986)$ (0.6) % 2,114 2,103 327,644 321,797 South Dakota 53,764 53,408 356 0.7 % 435 481 51,395 51,224 Residential 357,892 359,522 (1,630) (0.5) % 2,549 2,584 379,039 373,021 Montana 310,813 324,632 (13,819) (4.3) % 2,410 2,435 75,712 74,294 South Dakota 84,182 77,736 6,446 8.3 % 834 834 13,070 12,972 Commercial 394,995 402,368 (7,373) (1.8) % 3,244 3,269 88,782 87,266 Industrial 34,803 33,986 817 2.4 % 2,190 1,961 80 79 Other 27,437 27,229 208 0.8 % 131 119 6,552 6,483 Total Retail Electric 815,127 823,105 (7,978) (1.0) % 8,114 7,933 474,453 466,849 Regulatory amortization 18,637 (80,085) 98,722 (123.3) % Transmission 70,573 57,092 13,481 23.6 % Wholesale and other 5,461 4,492 969 21.6 % Total Revenues 909,798 804,604 105,194 13.1 % Total fuel, purchased supply & direct transmission expense* 256,989 198,492 58,497 29.5 % Utility Margin 652,809$ 606,112$ 46,697$ 7.7 % * Direct transmission expense is exclusive of depreciation and depletion expense (in thousands) Revenues Change Megawatt Hours (MWH) Average Customer Counts Nine Months Ended September 30, 1 Electric Segment (YTD) (1) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure. 37 Appendix

2024 2023 $ % 2024 2023 2024 2023 Montana 75,933$ 94,074$ (18,141)$ (19.3) % 9,220 9,206 185,412 183,584 South Dakota 21,244 30,297 (9,053) (29.9) % 2,113 2,557 42,477 41,962 Nebraska 16,106 30,221 (14,115) (46.7) % 1,812 2,053 37,924 37,752 Residential 113,283 154,592 (41,309) (26.7) % 13,145 13,816 265,813 263,298 Montana 42,016 52,393 (10,377) (19.8) % 5,307 5,456 26,112 25,679 South Dakota 14,283 21,289 (7,006) (32.9) % 2,139 2,385 7,353 7,218 Nebraska 8,982 19,119 (10,137) (53.0) % 1,328 1,528 5,045 5,017 Commercial 65,281 92,801 (27,520) (29.7) % 8,774 9,369 38,510 37,914 Industrial 703 995 (292) (29.3) % 98 107 237 231 Other 1,036 1,282 (246) (19.2) % 156 155 196 189 Total Retail Electric 180,303$ 249,670$ (69,367)$ (27.8) % 22,173 23,447 304,756 301,632 - Regulatory amortization 18,686 (21,312) 39,998 (187.7) % Wholesale and other 31,645 33,172 (1,527) (4.6) % Total Revenues 230,634$ 261,530$ (30,896)$ (11.8) % Total fuel, purchased supply & direct transmission expense* 82,100$ 123,521$ (41,421)$ (33.5) % Utility Margin 148,534$ 138,009$ 10,525$ 7.6 % * Direct transmission expense is exclusive of depreciation and depletion expense Revenues Nine Months Ended September 30, (in thousands) Change Dekatherms (Dkt) Average Customer Counts 1 Natural Gas Segment (YTD) 38 Appendix (1) Utility Margin is a non-GAAP Measure. See appendix slide titled “Reconciling Gross Margin to Utility Margin” for additional disclosure.

Q1 Q2 Q3 Q4 Full Year '17/'18 Tracker $3.3 $3.3 '18/'19 Tracker ($5.1) $0.3 (4.8) 2018 (Expense) Benefit $0.0 $0.0 ($1.8) $0.3 ($1.5) Full Year '18/'19 Tracker ($1.6) $4.6 $3.0 '19/'20 Tracker $0.1 ($0.7) (0.6) 2019 (Expense) Benefit ($1.6) $4.6 $0.1 ($0.7) $2.4 Full Year ($9.4) ($9.4) '19/'20 Tracker ($0.1) $0.2 $0.1 Recovery of modeling costs $0.7 $0.7 '20/'21 Tracker ($0.6) ($0.3) ($0.9) 2020 (Expense) Benefit $0.6 $0.2 ($0.6) ($0.3) ($0.1) Full Year '20/'21 Tracker ($0.8) ($0.5) ($1.3) '21/'22 Tracker ($2.7) ($1.4) ($4.1) 2021 (Expense) Benefit ($0.8) ($0.5) ($2.7) ($1.4) ($5.4) Q1 Q2 Q3 Q4 Full Year '21/'22 Tracker ($0.8) ($0.8) ($1.6) '22/'23 Tracker ($3.9) ($1.7) ($5.6) 2022 (Expense) Benefit ($0.8) ($0.8) ($3.9) ($1.7) ($7.2) Q1 Q2 Q3 Q4 Year-to-Date '22/'23 Tracker $0.5 $2.1 $2.6 Retro-active application of PCCAM base $3.2 $3.2 '23/'24 Tracker $0.1 $1.1 $1.2 2023 (Expense) Benefit $0.5 $2.1 $0.1 $4.3 $7.0 Q1 Q2 Q3 Q4 Year-to-Date '23/'24 Tracker ($3.0) $1.2 ($1.8) '24/'25 Tracker $0.7 $0.7 2024 (Expense) Benefit ($3.0) $1.2 $0.7 $0.0 ($1.1) Year-over-Year Variance ($3.5) ($0.9) $0.6 ($3.8) CU4 Disallowance ('18/'19 Tracker) First full year recorded in Q3 PCCAM Impact by Quarter Qualified Facility Earnings Adjustment Our electric QF liability consists of unrecoverable costs associated with contracts covered under PURPA that are part of a 2002 stipulation with the MPSC and other parties. Risks / losses associated with these contracts are born by shareholders, not customers. Therefore, any mitigation of prior losses and / or benefits of liability reduction also accrue to shareholders. 39 Appendix Pretax millions – shareholder (detriment) benefit

(dollars in millions) As of September 30, As of December 31, 2024 2023 Cash and cash equivalents 2.5$ 9.2$ Restricted cash 25.4 16.0 Accounts receivable, net 144.2 212.3 Inventories 121.6 114.5 Other current assets 74.8 55.0 Goodwill 357.6 357.6 PP&E and other non-current assets 7,128.1 6,836.1 Total Assets 7,854.1$ 7,600.7$ Payables 93.7 124.3 Current Maturities - debt and leases 403.4 103.3 Other current liabilities 316.1 307.3 Long-term debt & capital leases 2,570.7 2,690.1 Other non-current liabilities 1,653.6 1,590.3 Shareholders' equity 2,816.5 2,785.3 Total Liabilities and Equity 7,854.1$ 7,600.7$ Capitalization: Short-Term Debt & Short-Term Finance Leases 403.4 103.3 Long-Term Debt & Long-Term Finance Leases 2,570.7 2,690.1 Less: Basin Creek Finance Lease (6.3) (8.8) Shareholders' Equity 2,816.5 2,785.3 Total Capitalization 5,784.3$ 5,569.9$ Ratio of Debt to Total Capitalization 51.3% 50.0% Balance Sheet 40 Appendix Debt to Total Capitalization up from last quarter and inside our targeted 50% - 55% range.

(dollars in millions) 2024 2023 Operating Activities Net Income 143.6$ 111.0$ Non-Cash adjustments to net income 175.3 141.1 Changes in working capital 35.9 194.5 Other noncurrent assets & liabilities (10.9) (19.6) Cash Provided by Operating Activities 343.9 427.0 Cash Used in Investing Activities (405.1) (411.0) Cash Provided by (Used In) Financing Activities 63.9 (16.8) Cash Provided by Operating Activities 343.9$ 427.0$ Less: Changes in working capital 35.9 194.5 Funds from Operations 308.0$ 232.5$ PP&E additions 400.5 407.2 Capital expenditures included in trade accounts payable (16.4) (21.4) AFUDC Credit 15.4 12.5 Total Capital Investment 399.5$ 398.4$ Nine Months Ended September 30, Cash from Operating Activities decreased by $83.1 million primarily due to significant net cash inflows in the prior period from the recovery of previously under- collected energy supply costs, compared to minimal net cash inflows in the current period due to the timely recovery of energy supply costs. Funds from Operations increased by $75.5 million over prior period. Net Under-Collected Supply Costs (in millions) Beginning (Jan. 1) Ending (Sept. 30) (Outflow) / Inflow 2023 $115.4 $16.6 $98.8 2024 $7.8 $1.8 $6.0 2024 Decrease in Net Cash Inflows $(92.8) Year-to-Date Cash Flow 41 No Planned Equity Issuances in 2024 Financing plans (targeting a FFO to Debt ratio > 14%) are expected to maintain our current credit ratings and are subject to change. Debt financing in 2024 • Issued $175 million, 5.56% coupon, 7 year Montana FMBs in Q1 • Issued $33 million, 5.55% coupon, 5 year South Dakota FMBs in Q1 • Issued $7 million, 5.75% coupon, 10 year, South Dakota FMBs in Q1 • Entered $100 million term loan in Q2 with variable rate of Secured Overnight Financing Rate plus an applicable margin. Appendix

Reconciling Gross Margin to Utility Margin Management believes that Utility Margin provides a useful measure for investors and other financial statement users to analyze our financial performance in that it excludes the effect on total revenues caused by volatility in energy costs and associated regulatory mechanisms. This information is intended to enhance an investor's overall understanding of results. Under our various state regulatory mechanisms, as detailed below, our supply costs are generally collected from customers. In addition, Utility Margin is used by us to determine whether we are collecting the appropriate amount of energy costs from customers to allow recovery of operating costs, as well as to analyze how changes in loads (due to weather, economic or other conditions), rates and other factors impact our results of operations. Our Utility Margin measure may not be comparable to that of other companies' presentations or more useful than the GAAP information provided elsewhere in this report. (1) Utility Margin is a non-GAAP Measure. 42 Appendix 2024 2023 2024 2023 2024 2023 (in millions) Reconciliation of gross margin to utility margin Operating Revenues 306.5$ 280.0$ 38.7$ 41.1$ 345.2$ 321.1$ Less: Fuel, purchased supply and direct transmission expense (exclusive of depreciation and depletion shown separately below) 80.8 78.0 7.1 10.9 87.9 88.9 Less: Operating & maintenance expense 42.5 40.0 13.4 13.2 55.9 53.2 Less: Property and other tax expense 32.3 33.7 9.3 9.6 41.6 43.3 Less: Depreciation and depletion expense 47.6 43.3 9.4 8.9 57.0 52.2 Gross Margin 103.3 85.0 (0.5) (1.5) 102.8 83.5 Plus: Operating & maintenance expense 42.5 40.0 13.4 13.2 55.9 53.2 Plus: Property and other tax expense 32.3 33.7 9.3 9.6 41.6 43.3 Plus: Depreciation and depletion 47.6 43.3 9.4 8.9 57.0 52.2 Utility Margin 225.7$ 202.0$ 31.6$ 30.2$ 257.3$ 232.2$ 2024 2023 2024 2023 2024 2023 (in millions) Reconciliation of gross margin to utility margin Operating Revenues 909.8$ 804.6$ 230.6$ 261.5$ 1,140.4$ 1,066.1$ Less: Fuel, purchased supply and direct transmission expense (exclusive of depreciation and depletion shown separately below) 257.0 198.5 82.1 123.5 339.1 322.0 Less: Operating & maintenance expense 126.3 123.8 41.1 40.1 167.4 163.9 Less: Property and other tax expense 96.6 103.0 28.4 29.6 125.0 132.6 Less: Depreciation and depletion expense 142.4 130.5 28.2 27.3 170.6 157.8 Gross Margin 287.5 248.8 50.8 41.0 338.3 289.8 Plus: Operating & maintenance expense 126.3 123.8 41.1 40.1 167.4 163.9 Plus: Property and other tax expense 96.6 103.0 28.4 29.6 125.0 132.6 Plus: Depreciation and depletion 142.4 130.5 28.2 27.3 170.6 157.8 Utility Margin 652.8$ 606.1$ 148.5$ 138.0$ 801.3$ 744.1$ Reconciliation of Gross Margin to Utility Margin for the Three Months Ended September 30, Reconciliation of Gross Margin to Utility Margin for the Nine Months Ended September 30, Electric Natural Gas Total Electric Natural Gas Total (1) (1)

Non-GAAP Financial Measures 43 Appendix

Non-GAAP Financial Measures This presentation includes financial information prepared in accordance with GAAP, as well as other financial measures, such as Utility Margin, Adjusted Non-GAAP pretax income, Adjusted Non-GAAP net income and Adjusted Non-GAAP Diluted EPS that are considered “non-GAAP financial measures.” Generally, a non-GAAP financial measure is 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. We define Utility Margin as Operating Revenues less fuel, purchased supply and direct transmission expense (exclusive of depreciation and depletion) as presented in our Consolidated Statements of Income. This measure differs from the GAAP definition of Gross Margin due to the exclusion of Operating and maintenance, Property and other taxes, and Depreciation and depletion expenses, which are presented separately in our Consolidated Statements of Income. A reconciliation of Utility Margin to Gross Margin, the most directly comparable GAAP measure, is included in this presentation. Management believes that Utility Margin provides a useful measure for investors and other financial statement users to analyze our financial performance in that it excludes the effect on total revenues caused by volatility in energy costs and associated regulatory mechanisms. This information is intended to enhance an investor's overall understanding of results. Under our various state regulatory mechanisms, as detailed below, our supply costs are generally collected from customers. In addition, Utility Margin is used by us to determine whether we are collecting the appropriate amount of energy costs from customers to allow recovery of operating costs, as well as to analyze how changes in loads (due to weather, economic or other conditions), rates and other factors impact our results of operations. Our Utility Margin measure may not be comparable to that of other companies' presentations or more useful than the GAAP information provided elsewhere in this report. Management also believes the presentation of Adjusted Non-GAAP pre-tax income, Adjusted Non-GAAP net income and Adjusted Non-GAAP Diluted EPS is more representative of normal earnings than GAAP pre-tax income, net income and EPS due to the exclusion (or inclusion) of certain impacts that are not reflective of ongoing earnings. The presentation of these non-GAAP measures is intended to supplement investors' understanding of our financial performance and not to replace other GAAP measures as an indicator of actual operating performance. Our measures may not be comparable to other companies' similarly titled measures. 44 Appendix

Thank youRate Review Appendix 45

Montana Electric Rate Review Montana Electric: • $69.4M Net Request • $874M Plant-in-Service additions (’23-’24F) • Operating Costs 1.1% CAGR (’21-’23) • Typical Residential Bill: 8.3% at full request 46 $156.5 Million Base Rate Increase Requested & $69.4 Million Total Request Typical 750 kWh Residential Electric Bill YCGS Net Customer Impact Appendix Plant in Service Additions

Montana Gas Rate Review 47 $28.6 Million Base Rate Increase Requested Montana Natural Gas: • $28.6M Total Request • $174M Plant-in-Service additions (’23-’24F) • Operating Costs 3.3% CAGR (’21-’23) • Typical Residential Bill: 17.0% at full request Typical 65 Therm Residential Natural Gas Bill Appendix Plant in Service Additions

South Dakota Natural Gas Rate Review 48 South Dakota Natural Gas: • $6.0M Total Request • $80M Plant-in-Service additions (’10-’23) • Operating Costs 1.9% CAGR (’10-’23) • Typical Residential Bill: 7.9% at full request $6.0 Million Rate Increase Requested Typical 100 Therm Residential Natural Gas Bill Appendix

Nebraska Natural Gas Rate Review 49 $3.6 Million Rate Increase Requested Typical 100 Therm Residential Natural Gas Bill Nebraska Natural Gas: • $3.6M Total Request • $42M Plant-in-Service additions (’07-’23) • Operating Costs 1.3% CAGR (’07-’23) • Typical Residential Bill: 5.8% at full request Appendix

Thank youDelivering a bright future 50

Document and Entity Information Document	Oct. 28, 2024
Cover [Abstract]
Document Type	8-K
Entity Registrant Name	NorthWestern Energy Group, Inc.
Entity File Number	000-56598
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	93-2020320
Entity Address, Address Line One	3010 W. 69th Street
Entity Address, City or Town	Sioux Falls
Entity Address, State or Province	SD
Entity Address, Postal Zip Code	57108
City Area Code	605
Local Phone Number	978-2900
Entity Emerging Growth Company	false
Title of 12(b) Security	Common stock
Entity Central Index Key	0001993004
Amendment Flag	false
Trading Symbol	NWE
Security Exchange Name	NASDAQ
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Document Period End Date	Oct. 28, 2024

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