Unitil : 1Q24 Earnings Call Supplement

FINANCIAL AND STRATEGIC UPDATE

May 7, 2024

Forward-Looking Statements and Use of Non-GAAP Measures

This presentation contains "forward-looking statements" including within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical fact, included in this presentation are forward-looking statements. These forward-looking statements include statements regarding Unitil Corporation and its subsidiaries' financial condition, results of operations, capital expenditures, business strategy, regulatory strategy, market opportunities, and other plans and objectives. In some cases, forward-looking statements can be identified by words such as "may," "will," "should," "expects," "plans," "anticipates," "believes," "estimates," "predicts," "potential" or "continue", the negative of such terms, or other comparable terminology. In this presentation, "Unitil," the "Company", "we", "us", "our" and similar terms refer to Unitil Corporation and its subsidiaries, unless the context requires otherwise.

These forward-looking statements are neither promises nor guarantees, but involve risks and uncertainties that could cause the actual results to differ materially from those set forth in the forward-looking statements. Those risks and uncertainties include: Unitil's regulatory and legislative environment (including laws and regulations relating to climate change, greenhouse gas emissions and other environmental matters); fluctuations in the supply of, demand for, and the prices of energy commodities and transmission capacity and Unitil's ability to recover energy commodity costs in its rates; customers' preferred energy sources; severe storms and Unitil's ability to recover storm costs in its rates; declines in the valuation of capital markets, which could require Unitil to make substantial cash contributions to cover its pension obligations, and Unitil's ability to recover pension obligation costs in its rates; general economic conditions, which could adversely affect (i) Unitil's customers and, consequently, the demand for Unitil's distribution services, (ii) the availability of credit and liquidity resources and (iii) certain of Unitil's counterparty's obligations (including those of its insurers and lenders);86,600Unitil's ability to obtain debt or equity financing on acceptable terms; increases in interest rates, which could increase Unitil's interest expense; restrictive covenants contained in the terms of Unitil's and its subsidiaries' indebtedness, which restrict certain aspects of Unitil's business operations; variations in weather, which could cause unanticipated changes in demand for Unitil's distribution services; long-term global climate change, which could cause unanticipated changes in customer demand or cause extreme weather events that could disrupt Unitil's electric and

Natural Gas Customers

natural gas distribution services; cyber-attacks, acts of terrorism, acts of war, severe weather, a solar event, an electromagnetic event, a natural disaster, the age and condition of information technology assets, human error, or other factors could disrupt Unitil's operations and cause Unitil to incur unanticipated losses and expense; outsourcing of services to third parties, which could expose Unitil to substandard quality of service delivery or substandard deliverables, which may result in missed deadlines or other timeliness issues, non-compliance (including with applicable legal requirements and industry standards) or reputational harm, which could negatively impact our results of operations; catastrophic events; numerous hazards and operating risks relating to Unitil's electric and natural gas distribution activities; Unitil's ability to retain its existing customers and attract new customers; increased competition; unforeseen or changing circumstances, which could adversely impact the reduction of company-wide greenhouse gas emissions; employee workforce factors, including the ability to attract and retain key personnel; other presently known or unforeseen factors; and other risks detailed in Unitil Corporation's filings with the Securities and Exchange Commission, including those appearing under the caption "Risk Factors" in Unitil Corporation's most recently filed Annual Report on Form 10-K.

Readers should not place undue reliance on any forward looking statements, which speak only as of the date they are made. Except as may be required by law, Unitil undertakes no obligation to update any forward-looking statements to reflect any change in Unitil's expectations or in events, conditions, or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

This presentation contains Non-GAAP measures. The Company's management believes these measures are useful in evaluating its performance. Reconciliations of Non-GAAP financial measures to the most directly comparable GAAP financial measures can be found herein.

SLIDE 2

Financial Results and Strategic Update

Strong financial results and continued strategic execution

Achieving Strong Financial Results

• 2024 Net Income of $27.2 million or $1.69 per share, through the first quarter
• $0.18 per share increase compared to the first quarter of 2023 supported by regulatory initiatives and customer growth
• 11.9% year-over-year EPS growth
• Minimal O&M expense increase of $0.1 million year-over-year
• GAAP ROE of 9.7%

Delivering on Long-term Goals	86,600
• Reaffirming long-term EPS growth rate of 5% - 7%	Natural Gas Customers

• Payout ratio firmly within target range of 55% - 65%

Executing Corporate Strategy and Operational Excellence

• Strong regulatory outcomes across jurisdictions
• Best-in-classoperational performance and top-tier customer service
• 2024 Climate and Energy Sustainability Award Winner(1)

Solid Capital Investment Outlook

• Long-terminvestment requirements in system modernization and expansion
• Expected long-term rate base growth of 6.5% - 8.5%
• Utility-ScaleSolar project progressing as planned

(1) Awarded by New Hampshire Businesses for Social Responsibility

SLIDE 3

Utility Scale Project in New Hampshire

Site work and construction underway for 5 MW Solar Facility in Kingston, NH

Project Summary and Update

• Site work began in Q1 and is progressing as expected
• PV Facility electrical design nearing completion
• Nominated for Project of the Year Energy Champion Award by Clean Energy New Hampshire
• Estimated capital cost of $14 million will be included in Rate Base

NH Statute RSA 374-G

• Enables utility ownership of DER, limited to 6% of utility's total distribution peak load (approximately 18 MW for Unitil)
• Individual generation projects limited to 5 MW
• Continue to evaluate and investigate additional solar opportunities

Timeline

Site



Initial



Intervenor



Joint Letter



Order



Site Work



Expected In

Seek Cost

Selection

Filing

Testimony

of Support

Received

Begun

Service

Recovery

August 25, 2022

October 31, 2022

March 9, 2023

March 23, 2023

May 1, 2023

Q1 2024

1H 2025

Shortly after

Completion

SLIDE 4

First Quarter 2024 Financial Results

Net Income and Earnings Per Share

Net Income of $27.2 million in the first quarter, or $1.69 per share

• Net Income increase of $3.1 million, or $0.18 per share, relative to the first quarter of 2023
• Earnings growth reflects higher Electric and Gas Adjusted Gross Margins, partially offset by higher operating expenses
• Warmer weather in the quarter affected earnings by approximately ($0.02) relative to the prior year and approximately ($0.10) relative to normal weather conditions

	Three Months Ended March 31
	2024	2023
Net Income ($ millions)	$27.2	$24.1
Earnings Per Share	$1.69	$1.51

SLIDE 5

Volume and Adjusted Gross Margin Variances

Year-to-Date variances in units, customers, and adjusted gross margin

	Electric Operations			Unit Sales and Customers
			•	Electric distribution revenue substantially decoupled (2)
Adjusted Gross Margin(1)	Weather Normalized Unit	Customers	•	Weather normalized Residential and C&I sales increased 0.5%
Sales		and 0.8%, respectively
			•	Approximately 500 additional customers
				Adjusted Gross Margin(1) Increased $0.4 Million
1.5% Increase	0.7% Increase	0.5% Increase	•	Reflects higher rates and customer growth
			•	Decoupling adjusted revenue by $1.1 million or $0.05 EPS
				Unit Sales and Customers
	Gas Operations
			•	60% of gas customers decoupled(2)
Adjusted Gross Margin(1)	Weather Normalized Unit	Customers	•	Weather normalized sales in Maine, our only non-decoupled
Sales		service area, increased 0.3%
			•	Approximately 1,100 additional customers
				Adjusted Gross Margin(1) Increased $6.1 Million
11.1% Increase	0.5% Increase	1.2% Increase	•	Higher rates and customer growth, partially offset by weather
			•	Decoupling adjusted revenue by $2.3 million or $0.11 EPS

1. Adjusted gross margin is a non-GAAP financial measure. Reconciliations from non-GAAP financial measures to GAAP financial measures are provided at the end of the presentation
2. Calculation based on customer counts as of March 31, 2024

SLIDE 6

First Quarter Earnings Reconciliation

Variances to prior period Net Income

• Adjusted Gross Margin(1) increased $6.5 million as a result of higher rates and customer growth, partially offset by warmer winter weather in 2024.
• Operation and Maintenance Expenses increased $0.1 million due to higher utility operating costs.
• Depreciation and Amortization increased $1.3 million reflecting higher levels of utility plant in service, higher amortization of storm and other deferred costs.
• Taxes Other Than Income Taxes increased $0.4 million due to higher local property taxes on higher utility plant in service and higher payroll taxes.
• Interest Expense, Net increased $0.2 million reflecting higher interest expense on short-term borrowings and higher levels of long-term debt, partially offset by higher interest income on regulatory assets.
• Other Expenses increased $0.3 million reflecting higher retirement benefit costs.
• Income Taxes increased $1.1 million reflecting higher pre-tax earnings in 2024.

$6.5	$0.1	$1.3	$0.4	$0.2	$0.3	$1.1

	$24.1								$27.2
	2023 NI	Adjusted Gross	O&M	Depreciation &	Taxes Other Than Interest Expense,	Other	Income	2024 NI
$ millions	Margin(1)		Amortization	Income Taxes	Net		Taxes

(1) Adjusted gross margin is a non-GAAP financial measure, reconciliations from non-GAAP financial measures to GAAP financial measures are provided at the end of the presentation

SLIDE 7

Fitchburg Rate Case Overview (Electric and Gas)

FG&E rate cases progressing on schedule and nearing conclusion

Rate Case Filing Details (1)

Docket Number	23-80 (electric) and 23-81 (gas)
Test Year	2022
Requested Common Equity Ratio	52.26% (Current Authorized: 52.50%)
Requested Rate of Return	Electric - 10.5%, Gas - 10.75%
Requested Electric Revenue Increase	$6.8 million
Requested Gas Revenue Increase	$11.2 million
Requested Rate Base	Electric $90.3 million, Gas $121.7 Million

(1) Rate case details reflect most recent filing on 05/01/2024, which may differ slightly from initial filing

Key Elements

• Five-yearPerformance Based Ratemaking plans with annual inflation-based adjustments to revenue
• • K-Barmechanism taking place of Capital Cost Adjustment Mechanism to recover base electric capital investments
  • Gas System Enhancement Program, Grid Modernization (electric) capital recovery mechanisms remain in place
• Roll-inof capital tracker revenues offsets revenue deficiency requests
• • Electric tracker transfer of $2.7 million
  • Gas tracker transfer of $4.2 million
• Maintains revenue decoupling

Evidentiary hearings concluded; anticipate new base distribution rates to take effect July 1, 2024

Supports Stakeholder Interests

Provides cost mitigation		Aligned with
and efficiency incentives		regulatory precedent

Supports decarbonization	Promotes customer bill
policy initiatives	stability

SLIDE 8

Massachusetts Electric Sector Modernization Plan (ESMP)

Capital investments to optimize electric system capacity and technological improvements

ESMP Summary

• Comprehensive distribution and technology investment plan to:
• • Improve reliability and resiliency
  • Increase timely adoption of renewable energy resources
  • Promote energy storage and electrification technologies
  • Prepare for future climate-driven impacts on the electric system
  • Accommodate increased electrification from transportation, building and other potential demands
  • Minimize or mitigate the impact to ratepayers while helping the Commonwealth realize its greenhouse gas emission limits
• Includes capital investment totaling $43 million through 2028
• Timely recovery through proposed capital tracker mechanism
• Strategies and frameworks to ensure community engagement and transparency
• Filed January 29, 2024

Currently Approved Programs

• Grid Modernization - $24.1 million authorized investment from 2022 - 2025
• EV Make Ready - $1.0 million authorized 2023 - 2027

Plan supports

Commonwealth's goal of achieving economy-wide net zero greenhouse gas emissions by

2050

SLIDE 9

Significant Investment Opportunities

Anticipate long-term rate base growth of 6.5% to 8.5%

Historical Rate Base Growth

$s in Millions

$1,200 Five-year CAGR of 7.3% approximates mid-point of long-range guidance $1,000

$800 $600 $400 $200 $0

2018

2019

2020

2021

2022

2023

Long-Term Financing Sources

Equity, 13%

Debt, 25%

CFFO, Less

Dividends, 62%

Equity includes internally

generated funds such as the

Dividend Reinvestment Program

Actual and Forecast Capital Investment(1)

$s in Millions	Five-year projected capital investment of approximately $910 million, 47% higher than prior five years
		$200
				$176	$180	$187
			$168
	$122	$141
	2022	2023	2024F	2025F	2026F	2027F	2028F
(1)	Forecast investment includes capitalized non-service retirement benefit costs which aren't reflected as investing activity for GAAP			SLIDE 10