#1AltaGas Investor Presentation August 2018#2Forward-looking Information This presentation contains forward-looking statements. When used in this presentation, the words "will", "intend", "plan", "potential", "generate", "grow", "deliver", "can", "continue", "drive", "anticipate", "target", "come", "create", "position", "achieve", "seek", "propose", "forecast", "estimate", "expect", "solution", "outlook", "assumes" and similar expressions, as they relate to AltaGas or any affiliate of AltaGas, are intended to identify forward-looking statements. In particular, this presentation contains forward-looking statements with respect to, among others things, business objectives; strategies; expected returns; expected growth (including growth in normalized EBITDA, normalized funds from operations, dividends, payout ratios, customers, rate base and the components thereof) and sources of growth; capital spending; cash flow and sources of funds; results of operations; performance; expectations regarding growth and development projects and other opportunities; expected strong accretion of EPS and FF/share; expected dividend, EBITDA and FFO growth; anticipated value, quality and type of secured and advanced growth opportunities; expected EBITDA by segment; expected financing strategy, including potential asset monetizations and securities offerings and the anticipated value of each element; the expected production growth in the Marcellus and Montney; expected cost, in service timing, capacity, supply, demand and benefits of RIPET; expected timing, capacity and benefits of the Marcellus investments; expected rate base; expected capex by segment and project; potential growth opportunities from clean energy in the power segment; targeted financial metrics and performance indicators, including expected maintenance of a BBB credit rating, expected FFO/debt and net debt/EBITDA rations; expected timing, cost and scale of the MCP; planned Montney midstream projects; expected impacts of US tax reform; Painted Pony's expected production growth; expected completion of Townsend 2B; expected rate cases at AltaGas' utilities; and potential battery storage opportunities. Information and statements contained in this presentation that are not historical facts may be forward-looking statements. These statements involve known and unknown risks, uncertainties and other factors that may cause actual results or events to differ materially from those anticipated in such forward-looking statements. Such statements reflect AltaGas' current views with respect to future events based on certain material factors and assumptions and are subject to certain risks and uncertainties, including, without limitation, changes in market competition, governmental or regulatory developments, changes in political environment, changes in tax legislation, general economic conditions, capital resources and liquidity risk, market risk, commodity price, foreign exchange and interest rate risk, operational risk, volume declines, weather, construction, counterparty risk, environmental risk, regulatory risk, labour relations, the anticipated benefits of the WGL Transaction may not materialize or may not occur within the time periods anticipated by AltaGas, impact of significant demands placed on AltaGas and WGL as a result of the WGL Transaction, failure by AltaGas to repay the bridge financing facility, potential unavailability of the bridge financing facility and/or alternate sources of funding that would be used to replace the bridge financing facility, including asset sales on desirable term; the impact of acquisition-related expenses, accuracy and completeness of WGL's publicly disclosed information, increased indebtedness of AltaGas after the closing of the WGL Transaction, including the possibility of downgrade of AltaGas' credit ratings, historical and pro forma combined financial information may not be representative of future performance, potential undisclosed liabilities of WGL, ability to retain key personnel of WGL following the WGL acquisition, risks associated with the loss of key personnel, risks relating to unanticipated costs of integration in connection with the WGL acquisition, including operating costs, customer loss or business disruption, changes in customer energy usage, and other factors set out in AltaGas' continuous disclosure documents. Many factors could cause AltaGas' or any of its business segments' actual results, performance or achievements to vary from those described in this presentation including, without limitation, those listed above as well as the assumptions upon which they are based proving incorrect. These factors should not be construed as exhaustive. Should one or more of these risks or uncertainties materialize, or should assumptions underlying forward-looking statements prove incorrect, actual results may vary materially from those described in this presentation as intended, planned, anticipated, believed, sought, proposed, forecasted, estimated or expected, and such forward-looking statements included in this presentation herein should not be unduly relied upon. These statements speak only as of the date of this presentation. AltaGas does not intend, and does not assume any obligation, to update these forward-looking statements except as required by law. The forward-looking statements contained in this presentation are expressly qualified by this cautionary statement. Financial outlook information contained in this presentation about prospective financial performance, financial position or cash flows is based on assumptions about future events, including, without limitation, economic conditions and proposed courses of action, based on management's assessment of the relevant information currently available. Readers are advised to refer to AltaGas' news release announcing the acquisition of WGL for a further description of the assumptions underpinning the financial outlook information contained in this presentation relating to the combination of AltaGas and WGL. Readers are cautioned that such financial outlook information contained in this presentation should not be used for purposes other than for which it is disclosed herein. In this presentation we use certain supplementary measures, including Normalized EBITDA, Normalized Funds from Operations ("FFO"), AFFO and net debt that do not have any standardized meaning as prescribed under U.S. generally accepted accounting principles ("GAAP") and, therefore, are considered non-GAAP measures. AltaGas' method of calculating these non-GAAP measures may differ from the methods used by other issuers. Readers are advised to refer to Alta Gas' Management's Discussion and Analysis ("MD&A") as at and for the three months ended March 30, 2018 for a description of the manner in which AltaGas calculates such non-GAAP measures and for a reconciliation to the nearest GAAP financial measure. In this presentation we also use the Non-GAAP measure "Earnings Before Interest and Taxes (EBIT)", which is disclosed in respect of WGL's business segments only. As described in WGL's latest annual report on Form 10-K filed with the SEC, WGL considers EBIT to be a performance measure that includes operating income, other income (expense), earnings from unconsolidated affiliates and is reduced by amounts attributable to non-controlling interests. EBIT is used in assessing the results of each segment's operations. Readers are also cautioned that these non-GAAP measures should not be considered as alternatives to other measures of financial performance calculated in accordance with GAAP. Additional information relating to AltaGas can be found on its website at www.altagas.ca. The continuous disclosure materials of AltaGas, including its annual and interim MD&A and Consolidated Financial Statements, Annual Information Form, Information Circular, material change reports and press releases, are also available through AltaGas' website or directly through the SEDAR system at www.sedar.com and provide more information on risks and uncertainties associated with forward-looking statements. Unless otherwise stated, dollar amounts in this presentation are in Canadian dollars. This presentation does not constitute an offer or solicitation in any jurisdiction or to any person or entity. No representations or warranties, express or implied, have been made as to the accuracy or completeness of the information in this presentation and this presentation should not be relied on in connection with, or act as any inducement in relation to, an investment decision. AltaGas 2#3AltaGas Leading North American diversified energy infrastructure company AltaGas -$17 Billion Total Enterprise Value¹ Strong Accretion to both EPS and FFO/share2 metrics Visible dividend growth (2019-2021) $6 Billion ~$4.5 Secured growth ~$1.5 Advanced growth opportunities Diversification (3 segments, 8 utility jurisdictions, in over 30 states and provinces) Strong investment grade balance sheet ~$23 Billion Stable high quality assets AltaGas 1 Based on estimated book value at December 31, 2018 2 Funds from Operations is a Non-GAAP financial measure Expectations as at August 1, 2018 See "forward-looking information 3#4Significant Energy Infrastructure Platform High-quality, contracted assets with attractive organic growth ~2 Bcf/d1 of Natural Gas transacted ~70,000 Bbls/d liquids produced 1,690 Mmcf/d of extraction capacity ■ ~900 Mmcf/d of FG&P capacity 2 export terminals² Interest in four major pipelines in Marcellus / Utica 1,930 MW of Power Generation 1,259 MW Gas 277 MW Hydro 117 MW Wind 35 MW Biomass 20 MW Energy Storage 222 MW Distributed Generation ~$5B3 Utility Rate base ~1.8 million customers 8 Jurisdictions Alberta, B.C. and Nova Scotia in Canada Alaska, District of Columbia, Maryland, Michigan and Virginia in the U.S. ~75% U.S. normalized EBITDA contribution ~25% Canadian normalized EBITDA contribution ~80% normalized EBITDA contracted with medium and long-term agreements 1 AltaGas only; 2 AltaGas' 1/3 Ownership in Ferndale, and 70% Ownership in Ridley Island Propane Export Terminal; 3 AltaGas expectation as of December 2017, WGL extrapolated to calendar year end 2017 based on FY2017 rate base and a CAGR of 9.0%, US dollars converted C$1.26/US $1.00 AltaGas * Expectations as at August 1, 2018 ** Normalized EBITDA is a non-GAAP Financial Measure See "forward-looking information" 4#5Leading North American Diversified Energy Company Premier footprint in Canada and the U.S. Balanced Long-Term Target Business Mix Fee/ Take-or- Pay Cash PPA / Contract Cash Flow Midstream Power Flow Utility Regulated Cash Flow Gas Processing Regional LNG Facility LPG Export Terminal Distributed Generation Wind Power Generation Hydro Power Generation LPG Export Terminal Under Construction Storage Facility Storage Facility Under Construction Midstream Pipelines Midstream Pipelines Under Development AltaGas Biomass Power Generation Gas-Fired Power Generation Energy Storage Utilities 66 6 6 Segment normalized EBITDA1 (2017A) Gas 27% Power -37% Utilities -36% Segment normalized EBITDA² (2019F) 65 6 Gas Power -27%-32% -25% - 30% 66 7 Ο 1 AltaGas standalone 2 Expectations as at August 1, 2018, 2019E EBITDA is indicative, and based assumed asset monetizations. FX Rate of C$1.26/US$1.00 Normalized EBITDA is a non-GAAP measure. See "forward-looking information" Utilities -40% - 45% LO 5#6Financing Strategy Prudent plan achieves acquisition accretion metrics and maximizes shareholder value Acquisition financing - Completed ☐ Long-term financing plan structured to maintain strong investment grade credit profile C$2.1bn bought deal and C$400mm private placement of subscription receipts ■ Committed C$3.8bn acquisition bridge facility, 12 - 18 month asset sale bridge¹ Original bridge facility of C$6.3bn offset by issuance of $2.5bn in subscription receipts Acquisition financing - Outstanding ■ Monetization of assets of over C$2bn Sold a 35% minority interest in the Northwest B.C. Hydro Electric Facilities for $922 million Consideration also being given for potential of minority or majority interests, as well as outright sales of other assets Hybrids, preferred shares, and incremental debt provide funding flexibility for remaining portion Asset sales aligned with long-term business mix and are expected to close over the course of 2018 Acquisition funding sources (C$bn) ~$9.5 ~$3.4 -$2.4 ~$0.9 ~$2.8 $0.9 -$1.9 Total transaction value² Assumed debt³ Subscription receipts NWH Minority Interest Sale Bridge Loan Drawn Hybrids / Prefs Asset sales/term debt AltaGas 1 Bridge facility is denominated in US dollars (US$3bn with US-$2.3bn drawn at close of WGL), converted for presentation purposes to Canadian dollars at 1.26 CAD/USD; 2 Includes additional transaction related items; 3 Debt, Minority Interest and Preferred shares as of December 31, 2017, converted to Canadian dollars at 1.26 CAD/USD 60#7Attractive Platform for Growth Through 2021 ~C$6 billion of identified capital investment opportunities Energy Storage Canadian Midstream Montney Large Scale Power Development 102 U.S. Midstream Marcellus / Utica Footprint Canadian Utilities System Betterment and Customer Growth Distributed Generation $4.5 billion + $1.5 billion Secured growth Advanced growth opportunities U.S. Utilities System Betterment and Customer Growth AltaGas Expectations as at August 1, 2018 See "forward-looking information 7#8Midstream Operations in North America's Most Prolific Gas Plays Strategic infrastructure provides producers with global market access ☐ " ■ Unique opportunity providing critical infrastructure for energy exports at three sites on both the Pacific and Atlantic Only significant existing West Coast energy export terminal (Ferndale)1 with a second (RIPET) under construction, moving natural gas liquids to key markets including Asia High grade asset base in sustainable plays drive growth Strategic footprint in vertically integrated Montney & Marcellus / Utica plays 114 Montney expected to grow from -4.5 Bcf/d in 2016 to 8 Bcf/d by 20402 Gas Processing Regional LNG Facility LPG Export Terminal LPG Export Terminal Under Construction Storage Facility Storage Facility Under Construction Midstream Pipelines Midstream Pipelines Under Development AltaGas Appalachia production expected to grow from ~24 Bcf/d in 2017 to well over 30 Bcf/d³ 20-year GAIL Supply Agreement at Cove Point (Cove Point shipped first export cargo in March 20184) 1 AltaGas has 1/3 interest in Ferndale facility. 2 NEB - Energy Market Assessment. 3 U.S. Energy Information Administration. 4 Source: Desjardins Capital Markets, Natural Gas Report, March 8, 2018 Expectations as at August 1, 2018 See "forward-looking information" 8#9AltaGas' Northeast B.C. Strategy Provides new market access for Western Canadian propane producers to Asia Propane shipped to Asia Prince Rupert Blair Creek Raw gas Liquids mix piped to NGL facility and rail terminal Townsend North Pine Facility Younger Truck Terminal Liquids Pipelines (NGL mix and condensate) - Existing Liquids Pipelines (NGL mix and condensate) OFort St. John Ridley Island Propane Export Terminal (RIPET) $450 $500 Million¹ In service: Q1 2019 ☐ Expected to be Canada's first propane export terminal, located on B.C's west coast ■ Will provide producers with access to key markets to the west, including Asia, with significant shipping cost advantages vs. the Gulf coast ■ 40,000 Bbls/d of export capacity >40,000 bbl/d of C3 shipped to Asia C4 and C5+ railed to Propane railed to tidewater Fort Saskatchewan Fort Saskatchewan Ferndale Gas Processing Gas Processing Under Development Expansion to Existing Facility LPG Terminal LPG Terminal Construction Montney ++++ Rail Edmonton North Pine NGL Facility In service: Dec. 1, 2017 Townsend Phase 2A Gas Processing Facility In service: Oct. 1, 2017 ☐ ◉ NGL facility serving Montney producers in NE B.C. First train consists of 10,000 Bbls/d of C3+ processing capacity, with capacity of 6,000 Bbls/d of C5+ Connected by rail to Canada's west coast, including to RIPET Doubling the Townsend gas processing complex, phase two will consist of two separate gas processing trains First train (2A) is a 99 MMcf/d shallow-cut natural gas processing facility AltaGas 1 Total project cost; ownership is 70% ALA and 30% Royal Vopak Expectations at August 1, 2018 See "forward-looking information" 9#10IN AltaGas' Position in Marcellus Pipelines Connecting low cost producers with U.S. consumption markets and exports MI TN KY OH WV Marcellus / Utica Basins Central Penn ■■ Constitution Mountain Valley - Stonewall AltaGas PA MD VT NH NY DE NJ Cove point VA GAIL NC MA CT RI ME Stonewall US$135 Million Ownership: DTE (55%), ALA (30%), Antero (15%) Currently in service Designed to gather 1.4 Bcf/d from West Virginia Central Penn US$434 million Ownership: Williams (61%), ALA (21%), Ares/EIF (10%), Cabot (8%) Mountain Valley US$350 Million Ownership: EQT (45.5%), NextEra (31%), ConEd (12.5%), ALA (10%), RGC (1%) ☐ Designed to transport 1.7 Bcf/d as part of the "Atlantic Sunrise" project In service expected Q3 2018 Target in service Q1 2019 Designed to transport 2.0 Bcf/d from West Virginia to Virginia Constitution US$95 Million Ownership: Williams (41%), Cabot (25%), Duke/Piedmont (24%), ALA (10%) Designed to transport 0.65 Bcf/d to major northeastern markets GAIL Supply at Cove Point Natural gas sale and purchase agreement for a period of 20 years. ~2.5 mtpa of LNG (~0.35 Bcf/d) ■ Cove Point shipped first export cargo in March 20181 1 Source: Desjardins Capital Markets, National Gas Report, March 8, 2018 See "forward-looking information" 10#11Utility Business High quality assets underpinned by regulated, low-risk cash flow Delivering clean and affordable natural gas to homes and businesses in 8 jurisdictions Estimated combined rate base more than doubles and estimated combined customer base triples in size Increased diversification, across several high growth areas, minimizing exposure to any one jurisdiction ENSTAR NATURAL GAS COMPANY PNG Pacific Northern ~$7 Billion Projected rate base in 2021 ~1.8 Million customers across 8 states and provinces AltaGas Expectations as at August 1, 2018 See "forward-looking information" AltaGas utilities SEMCOENERGY GAS COMPANY Heritage Gas Washington Gas AWGL Com 11#12Customer Growth and Accelerated Replacements Drive Growth High near-term growth Expected near-term growth driven by customer additions, accelerated replacement programs and general system betterment capital expenditures Increased diversification into high growth areas such as Washington (6th largest regional economy in the U.S., among the highest median household incomes in the U.S.) Projected Rate Base Growth (C$ billions) ■Rate Base Replacements ~$5.2bn ■New business Other utility $2.8bn ~$8 bn AltaGas YE20171,2,3 Utility capex to 20213,4 Gross combined rate base 20215 1 As of December 2017 2 WGL extrapolated to calendar year end 2017 based on FY2016 rate base and a CAGR of 9.0% 3 WGL figures converted to Canadian C$1.26 / US $1.00 4 WGL Management estimates 5 Gross rate base excludes depreciation See "forward-looking information" 12#13Power Business Generating clean energy with natural gas and renewable sources Diversified Power Portfolio ■ 1,930 MW of power generation ■ Power generation in over 20 states and provinces ■ Contracts with creditworthy counterparties provide long- term stable cash flow Weighted average contract life is ~14 years¹ Enhanced growth from clean energy " Up to $350 million in new battery storage opportunities ■ -US$100 million per year in distributed generation opportunities ■ Over $300 million in new solar opportunities ☐ Strong footprint provides excellent opportunities to develop solar generation projects ធម៌ 66 Segment normalized EBITDA² (2019F) Utilities 40% - 45% Gas 27% -32% California Gas-fired generation, 10% Power 25% - 30% Northwest Hydro, 7% Distributed Generation, Energy Storage, 1% Power- Other, 7% ■ Track record of building projects on-time / ahead of schedule and under budget in both Canada and the U.S. 66 Distribution Generation Wind Power Generation Hydro Power Generation Biomass Power Generation Gas-Fired Power Generation Energy Storage AltaGas 66 646 1 Assumes average of 20 year contracts for WGL distributed generation 2 Expectations as at August 1, 2018 2019E EBITDA is indicative, and based upon assumed asset monitizations. FX Rate of C$1.26/US$1 See "forward-looking information ༢ 13#14Governing Financial Principles Delivering growth and security Principles 1 Dividend Sustainability 2 Target Expected Returns 3 4 Financing Requirements Strong Stable Investment Grade Balance Sheet Manageable Targeted Targets 50-60% FFO¹ payout ratio ✓ Expect -85% of 2019 common dividends to be underpinned by Regulated Utilities Enhancing returns on existing assets ✓ Specified targets for growth projects BBB credit rating Flexible financing plan to support growth using both growing internally generated cash flow and external financing (as required) 5 Managed Commodity Exposure ✓ ~85% or greater of contracted EBITDA 6 Strong Counterparty Creditworthiness Overall > 85% of exposure with investment grade counterparties² AltaGas 1 FFO is a non-GAAP financial measure 2 ALA standalone See "forward-looking information" 14#15Strong Investment Grade Credit Rating Prudent deal financing enhances balance sheet strength over the long-term 2016 FFO1/Debt -15% Target 2019 Net Debt/EBITDA ~5x Target 2016 2019 AltaGas 1 FFO is a non-GAAP financial measure See "forward-looking information" Combined larger platform and financing plan reinforce a path to improved credit metrics and a strong investment grade balance sheet Focus on stable cash flows Credit Metric FFO / Debt Net Debt/ EBITDA Target ≥ 15% ~ 5.0x 15#16Highly Contracted, Low-Risk Business Model Managed Commodity Exposure¹ 2019E (First full year including WGL) 13% 87% Highly Contracted 1,2 2019E (First full year including WGL) 72% 13% 9% 6% ■Stable EBITDA Commodity Based EBITDA ~13% of combined EBITDA exposed to commodity prices Commodity Exposed ■Medium-term (3-5 years) ■Short-term (< 3 years) ■Long-term (> 5 years) ~80% of normalized EBITDA underpinned by medium & long-term agreements High-quality cash flows underpinned by long-term take-or-pay contracts and rate regulated franchises AltaGas 1 Assumes RIPET is 40% underpinned by tolling agreements with balance being commodity exposed. Also assumes some commodity exposure for WGL (Energy Marketing). 2 Long term agreements includes rate-regulated gas utilities, Northwest BC hydro, regulated gas pipelines, WGL Contracted Pipelines, and long-term take-or-pay / cost-of-service midstream assets* Expectations as at August 1, 2018 See "forward-looking information" 16#170 2 4 6 14 Valuation Multiple Attractive value for AltaGas, combined with sustainable dividend payment. AltaGas has one of the lowest multiples in the entire sector. 12 Average 10 8 AltaGas Capital Power TransAlta Fortis Enbridge Income Emera Enbridge Inc 2019E P/AFFO1 Inter Pipeline TransCanada Pembina TransAlta Renewables Keyera Algonquin Power & Utilities Gibsons Innergex Renewables Northland Power See "forward-looking information" Boralex Brookfield Renewable Energy infrastructure group yield and growth² Yield 8% AltaGas Gibson 7% Attractive Valuation Inter Pipeline Enbridge IF Brookfield Capital Power Renewable 6% Enbridge 5% Algonquin Emera Pembina Innergex Northland Power Keyera TransCanada Canadian Utilities 4% Fortis 3% 0% 2% 4% 6% 8% 2-Year Dividend CAGR through 2018 10% 12% AltaGas 1 CIBC data, May 7, 2018. AFFO equals FFO adjusted for gas and power maintenance capital, preferred share dividends and non-controlling interest. AFFO is normalized which is a non- GAAP measure 2 Data provided by IR Insights 17#18Key Takeaways Near-term catalysts 2018 ☐ Debt/Hybrid Financing Further asset monetization initiatives to achieve an additional $1B in proceeds Potential new Gas and Power development initiatives Medium-term catalysts (12 - 24 Months) 2019-2020 ■ New battery storage and solar projects ■ New Midstream projects including Townsend 2B, and North Pine (train 2) Completion of Ridley Island Propane Export Terminal (Q1 2019) ■ Completion of Marquette Connector Pipeline in Michigan (Q4 2019) Strong rate base growth across Utilities Commitment to maintaining balanced long-term mix across 3 business lines AltaGas Expectations as at August 1, 2018 See "forward-looking information" 18#19AltaGas 1000 350 Appendix 371 344 390#2044 40 15 10 3322505 Fortis Larger Scale Enhances AltaGas' Competitive Position Peer Group Enterprise Value ($ billions) 50 45 TSX: ALA Today $CAD Common shares outstanding1 Common share trading price² 52-week trading range² Market capitalization² 266 million $27.49 $30.06-$22.82 Brookfield Renewable Pembina Pipeline Emera Canadian Utilities ~$17 billion energy infrastructure company AltaGas 2 As of August 1, 2018 See "forward-looking information" Alta Gas Inter Pipeline Northland Power Keyera Algonquin Power & Utilities 1 As of Q2 2018, plus conversion of subscription receipts and assumed WGL debt TransAlta $7.0 billion Preferred shares² $1.3 billion Net debt1 Total enterprise value² $8.9 billion $17.2 billion Corporate credit rating S&P DBRS Innergex Renewable Capital Power Boralex TransAlta Renewables Gibson Atlantic Power Increased diversification Expanded access to capital and greater financial flexibility BBB BBB 20 20#21Base Business Continues to Deliver Solid Financial Results Q2 2018 Achieved normalized EBITDA¹ of $166 million and normalized funds from operations¹ of $121 million Asset monetization strategy significantly progresses with sale of 35% indirect equity interest in the Northwest Hydro Facilities for $922 million ■ Further asset sales expected through Q3 2018 Integration activities well underway after closing of WGL acquisition Central Penn Pipeline expected to be in service in Q3 2018; RIPET and Mountain Valley Pipeline expected on-line in Q1 2019 2018 Outlook 25% - 30% EBITDA¹ growth 15% - 20% FFO1 growth AltaGas 1 Non-GAAP financial measure See "forward-looking statements & information" 102 21#22Successful track record of delivering EBITDA¹ growth over time Significant growth in 2018 driven by WGL Acquisition $ Millions 1,000 800 600 400 200 HI 0 2010 2011 2012 2013 2014 2015 2016 2017 2018F Non-commodity % of EBITDA¹ 25% - 30% growth² 2010 50% 2011 43% 2012 70% 2013 2014 2015 2016 2017 69% 79% 93% 98% 92% 2018F2 -90% AltaGas 1 Represents normalized EBITDA 2 Expectations as at August 1, 2018 2010 in accordance with CGAAP. 2011 and forward in accordance with U.S. GAAP See "forward-looking information" 22 22#23Contracted EBITDA¹ Substantial increase in long-term contracted and Regulated Gas Distribution EBITDA 4% 2010 34% 20% 29% 2018F2 -35% 13% -20% -35% Contracted PPA Midstream fee for service/TOP/cost of service Utilities/Regulated gas distribution Alberta power Frac Spread -10% Breakdown of Midstream EBITDA 1,2 50% Fixed/Take-or-pay ■ No volume or commodity price exposure Average contract length of ~18 years ■ 11% Cost-of-service Provides for recovery of operating costs and a capital charge, generally are not subject to commodity risk Average contract length of ~14 years 11% Fee-for-service ■ Provides for a fee per unit of production sold or service provided, generally are not subject to commodity risk 28% Frac Spread ■ Volume and price exposure ■ Over 70% of exposure is hedged in 2018 AltaGas 1 Represents normalized EBITDA 2 Expectations as at August 1, 2018, 2010 in accordance with CGAAP. 2017F in accordance with U.S. GAAP See "forward-looking information" 23 23#24Sound Financial Position Debt-to-Capitalization $ Millions 80% Covenants 2,500 2,000 60% 1,500 40% 1,000 20% 500 0% 0 2011 2012 2013 2014 2015 2016 2017 2011 6 x EBITDA-to-interest expense Covenants: 5 x No less than 2.5 x 4 x 3 x 2 x 1 x 0x 2011 2012 2013 2014 2015 2016 2017 See "forward-looking information" AltaGas Executed financing history 2012 2013 2014 2015 2016 2017 ■Common Equity Preferred Equity Debt Free Cash Flow ■DRIP Balanced capital structure (June 30, 2018) 16% 33% 51% Preferred ■Common ■Net Debt 24#25Debt Maturities Proforma long-term debt maturities¹ CAD $ Millions 2,000 1,800 1,600 1,400 1,200 1,000 800 600 400 200 2018 2019 2020 2021 2022 2023 ■ALA 2024 2025 ■SEMCO 2026 2027 2028 ■ PNG ■ WGL 2029 25 25 2030+ Balanced long-term debt maturities AltaGas "Moody's rating, not rated by S&P ** Negative outlook by S&P 1 WGL and SEMCO long-term debt converted at FX of 1.26 CAD/USD See "forward-looking information"#26Delivering Growth and Security Payout ratio balances company growth and investor return and positions ALA for further dividend growth Dividend growth¹ $2.19 $2.10 $1.98 $1.77 $1.53 $1.32 $1.38 $1.44 7.5% CAGR 49% Dividend payout2,3 57% 58% 55% 51% 46% III 42% illl 2011 2012 2013 2014 2015 2016 2017 2010 2011 2012 2013 2014 2015 2016 2017 2010 AltaGas 1 Based on annualized run rate 2 2010 in accordance with CGAAP. 2011 and forward in accordance with U.S. GAAP 3 Dividends paid as a percentage of FFO. See "forward-looking information" 26#27WGL Overview WGL is a leading diversified U.S. energy company Seen as a preferred source of clean and efficient energy solutions that produce value for customers, investors and communities Disciplined capital allocation strategy focused on infrastructure investments with numerous near-term opportunities Strong balance sheet and credit ratings (Moody's/S&P/ Fitch) WGL Holdings: (Baa1/BBB/BBB) Washington Gas: (A2/A-/A-) Utility Power EBIT Contribution By Segment5 Utility 67% Midstream 10% Commercial 10% Retail 13% 2017A Midstream Utility 60% Midstream 15% Commercial 15% Retail 10% 2020E Retail 2017A EBIT (%)1 Natural gas regulated utility serving 1.2 million customers with a rate base of C$3.3 billion 2,3 Serves three, high growth and economically strong jurisdictions: Washington D.C., Maryland and Virginia AltaGas Owns distributed generation assets including solar, and natural gas fuel cells The commercial segment is comprised of two businesses: Distributed generation Energy efficiency Stable earnings underpinned by contracts with a majority from investment grade counterparties Ownership stakes in four major midstream projects Expected to be the fastest growing segment through 2020 1 As of September 30, 2017, excludes other activities and eliminations; 2 WGL figures converted C$1.26 / US $1.00 3 WGL rate base extrapolated to calendar year end 2017 based on FY2017 rate base and a CAGR of 9.0%; 4 As per WGL FY2017A Form 10-K 5 WGL Standalone based on May 2016 Investor Presentation See "forward-looking information" Provides retail gas and electricity to 230,000 customers in Washington D.C., Maryland, Virginia, Delaware and Pennsylvania Volatility mitigated through five year secured supply arrangement with Shell4 Integrated service offering supporting other business lines 27#28Combined Scale to Deliver Growth AltaGas (C$mm) 1,2 1 Project Expected Capex Target In-Service Townsend 2B $80 2019/2020 $6 billion of identified opportunities support a diversified business mix North Pine Train 2 $50 2019/2020 Ridley Island Propane Export³ $333 2019 Central Penn Pipeline $547 2018 Mountain Valley Stonewall Expansion $441 2018 TBD TBD Constitution Pipeline $120 TBD Alton Gas Storage $155 2021 6 Processing / NGL separation $170 2019 Total Midstream $1,896 Pro Forma (C$bn) Business Capex Power Utilities capital Marquette pipeline4 CINGSA expansion New Business Replacements Other Utility $450 2018-2021 $173 2019 $33 2020 $831 2018-2021 $1,072 2018-2021 $326 2018-2021 Total Midstream $1.9 Utility Total Utility $2,884 Midstream Total Utility $2.9 Energy Storage* 4,5 $150 2018+ Total Power $1.0 Solar 4,6 $380 2019+ Total Pro Forma $5.8 Distributed Generation $502 2018-2021 Total Power Total Alta Gas $1,032 $5,812 AltaGas 1 Expectations based on most recent public disclosure / financial reports for AltaGas; 2 Reflects AltaGas' share of the total cost (both incurred and expected); 3 Reflects AltaGas' portion of project capital. Ownership will be 70% ALA and 30% Royal Vopak; 4 Based on a CAD/USD FX rate of 1.26 5 Energy storage capital ranges from $50 million to $350 million and represents a single project up to multiple projects; 6 Project may include a partner See "forward-looking information" - Note: Numbers may not add due to rounding 28 28#29U.S. Tax Reform - Implications for AltaGas Impact of U.S. tax reform on overall business is not expected to be material Regulated Business: Utilities Decrease in customer rates will result in a top line utility revenue drop as less tax is recovered Slightly negative impact to EBITDA and FFO and minimal impact on net income Revaluation of regulated deferred tax liability expected to be paid back over remaining useful life of assets Non-material impact to FFO and minimal impact on net income Once cash taxable, impact of decreased customer rates and revaluation of deferred tax liability will be neutral to FFO Reduced customer rates mitigates rate impact resulting from utilities replacement investments Interest expense deduction retained MACRS remains as tax depreciation method Non-Regulated Business: Midstream and Power Positive impact on net income driven by lower corporate tax rate Interest expense limitations are more than offset by lower corporate tax rate and accelerated tax depreciation Overall forecasted impact Pro-forma Metric (Normalized) 2018 2019 Expected Impact Expected Impact EBITDA / ~ (-5%) - (-5%) FFO Net Income ~ +5% - +2% AltaGas See "forward-looking information" 29 29#30U.S. Tax Reform - State Regulatory Update Michigan Alaska D.C. Virginia Maryland Commission Action Regulated utilities have been ordered to report how lower taxes will benefit customers Regulated utilities have been asked to submit proposals on how tax reductions will be flowed through to customers. All regulated utilities shall track the impact of tax reform and provide for appropriate accruals effective Jan 1, 2018. This included the revenue requirement impact and the impact from the revaluation of the deferred tax liability. Company Proposal AltaGas has proposed an immediate rate reduction using last filed rate case calculated using the new federal tax rate. Adjustment to deferred tax liability to factor into next rate case. CINGSA proposed to address the income tax expense reduction impact in its April 30 rate case filing and adjustments to deferred taxes to factor into that rate case.. ENSTAR is expected to file a revised tariff by the end of April to pass on savings to customers and adjustments to deferred income tax to factor into next rate case. WGL has proposed an immediate rate reduction using the last filed rate case calculated using the new federal rate. The impact of the revaluation of the deferred tax liability has also been factored into the rate reduction. Status Michigan PSC has established expedited regulatory process to consider utility's proposals in order to effectuate rate reductions to customers. • Awaiting further action from the Regulatory Commission of Alaska. AltaGas See "forward-looking information" Commission has approved WGL's submission 30#31AltaGas' Key Focus Areas Greenhouse Gas Emissions* Total Recordable Injury Frequency 4 1.50 3 SAFETY AND 1.00 2 ENVIRONMENT 0.50 1 0.00 0 2013 2014 2015 2016 2013 2014 2015 2016 PEOPLE ■Million tonnes of CO2 equivalent *Gas Division SOCIAL RESPONSIBILITY BUSINESS EXCELLENCE M GROWTH AltaGas See "forward-looking information" CDP Scores 2017 AltaGas Ltd. B Industry Average C Sector Average Canada Average Total Average Alberta's TOP 70 EMPLOYERS 2018 ROBECOSAM Sustainability Award Bronze Class 2017 EMPLOYERS TOP E CANADA'S 2017 FOR YOUNG PEOPLE 31#32Gas NO SMOKING TUG CRYSTAL RIVER#33Building Infrastructure to Serve New Markets From wellhead to markets Existing assets Growth projects Abundant natural North Pine NGL facility and other new processing infrastructure & liquids separation gas RAW GAS Extraction, processing & liquids separation NGL Storage, rail & truck offloading² New storage, rail, pipeline & truck offloading Rail, Fort Sask. hub² truck & pipelines² North American Markets Ferndale Terminal¹ (Exports commenced in 2014) Asian Markets Ridley Island Propane Export Terminal (RIPET) PROCESSING / FRAC Younger • Harmattan • Blair Creek Gordondale • Townsend LOGISTICS • North Pine • END MARKETS • Petrogas Ferndale RIPET • Astomos • Idemitsu Other third parties Fully-integrated, customer-focused value chain provides increased value to producers AltaGas 1 Current supply for Ferndale is sourced through Petrogas. 2 Includes Petrogas operations See "forward-looking information" 333#34Key Midstream Assets Providing customers with integrated market access 30,000 Bbl/d LPG 490 Mmcf/d ALA Key Assets FG&P Extraction Fractionation Terminal Operator Capacity (Inlet) RIPET Export 40,000 Bbl/d+ Ferndale Export Harmattan Rail Younger Rail JEEP EEEP PEEP Townsend Townsend 2A Gordondale Blair Creek North Pine Regional LNG Rail 212 Mmcf/d (net) 250 Mmcf/d 390 Mmcf/d 135 Mmcf/d (net) 198 Mmcf/d 99 Mmcf/d 150 Mmcf/d 83 Mmcf/d 10,000 Bbl/d 30,000 usgal/d AltaGas 34 ==#35Stable Production Volumes & Throughput Core plants in sustainable plays Mmcf/d 1,600 Gross Annual Throughput 1,200 800 400 0 2015 2016 A 2017 A Other Extraction Harmattan take or pay 2018F FG&P: ~500 Mmcf/d* 2018F extraction: ~1 Bcf/d Blair Creek 2016 66 Mmcf/d 2017 57Mmcf/d 2018E-60-70 Mmcf/d Gordondale 2016 90 Mmcf/d 2017-94 Mmcf/d 2018E 100 - 110 Mmcf/d Harmattan 2016 109 Mmcf/d 2018 E ■■Harmattan raw gas processing Other FG&P** ■Blair Creek Extraction Volumes * 2017 101 Mmcf/d 2018E-95 105 Mmcf/d³ Townsend¹ 2017 154 Mmcf/d - 2018E 255 - 265 Mmcf/d Younger4 ■Gordondale * ■ Townsend * 40,000 30,000 20,000 10,000 0 2015 2016 ■C2 Produced AltaGas 2017 ■Non-commodity exposed C3+ 2018E2 Exposed C3+ 2016 290 Mmcf/d 2017 267 Mmcf/d 2018E-210 - 220 Mmcf/d5 Other FG&P 2016 90 Mmcf/d 2017 87 Mmcf/d 2018E 70-80 Mmcf/d6 1 Includes Townsend and Townsend 2A 2 Expectations as at August 1, 2018 3 Includes a turnaround in 2018 4 Volumes net to AltaGas 5 Reflects reduced ownership percentage for April onwards 6 Reflects sale of Acme and Shaunovan * All or large majority of volumes are take-or-pay commitments **2015 total volumes exclude 2015 average volumes for assets sold to Tidewater. Acme, Ante Creek and ECNG sold in 2014 See "forward-looking information" 35#36Gordondale: New Long-Term Processing Arrangement Maximizing the long-term value and returns of deep cut facility New long-term take-or-pay agreement for at least 15 years ■ Agreement provides stable long-term cash flow by filling the existing operational capacity of 120 Mmcf/d Enables AltaGas to source third party gas for the first time, in addition to Birchcliff ☐ Active discussions with third party producers to tie in additional gas from the Gordondale/Pouce Coupe area within the liquids rich Alberta Montney Incremental volumes will maximize existing licensed capacity of 150 Mmcd/d (2017A volumes were 100 Mmcf/d)1, and lay the ground work for future plant expansion Growing propane volumes to be dedicated to AltaGas' Ridley Island Propane Export Terminal AltaGas 1 Excluding planned turnaround. Including turnaround volumes were 94 Mmcf/d * Expectations as at August 1, 2018. See "forward-looking information" 36#37Montney Competitive at Current Prices Competitive Canadian Production 1,2 94-G-11 94-G-10 USD/Mcfe $2.50 Painted Pony field cash cost estimated at $1.30 USD/Mcfe3 $2.00 $1.50 Avg. CDN producer cash cost $1.00 $0.50 $0.00 USD/Mcfe $3.00 $2.50 $2.00 $1.50 $1.00 $0.50 $0.00 AltaGas PEY AAV ΠΟΙ EQT COG SWN BNP BIR PMT PNE ARX RRC CR SRX VII KEL Producers Marcellus Producers Unhedged Cash Flow Margin $/Mcfe (incl. taxes)1 CHK 93-0-14 94-B-6 94-B-14 94-G-6 Avg. CDN producer cash flow margin4 Painted Pony cash margin estimated at -$0.93 USD/Mcfe³ Westcoast to Intra-B.C./U.S. Border Station 2 COG DEE RRC SWN PMT AR CQE PNE BXE Canadian Producers 1 Peters report April 2018 2 BMO data, April 2018 Marcellus Producers 3 Painted Pony May 2018 Investor Presentation, Based on a CAD/USD FX rate of 1.26 4 Cash costs including transportation, operating costs, G&A and interest expense 5 Unhedged cash flow (net of royalties) Map Source: Peters report See "forward-looking information" 93-0-6 Jedney 94-6-9 94-H-12 94-H-11 94-H-10 Laprise Birley 94-H-9 R12W6 Current Capacity (Bcf/d) Future Capacity (Bcf/d) Groundbirch Mainline (TRP) Alliance (ENB/VSN) Westcoast System (ENB) North Montney Mainline (TRP Future) - Towerbirch Expansion (TRP Future) Beg Nig ARX Black Swan POU-TODD Progress Canbriam Saguaro CKE Shell Umbach Birch COP SRX CR SU Town Gundy Blueberry ECA του KEL TOU-ARX Joint PPY Kobes Fireweed Inga Bemadet Attachie Altares 1.5 Bcf/d (2019+) 2.0 Bcf/d 2.2 Bcf/d (2020+) 0.8 Bcf/d 0.85 Bcf/d (H2/18) 93-0-3 geoSCOUT www.geologis.com 93-0-1 93-P-3 Oak T88 T86 Alliance to Chicago T84 1.6 Bcf/d 2.1 Bcf/d (2020+) Septimus Tower Groundbirch Sunset Parkland Sunrise 2.4 Bcf/d 3.0 Bcf/d (04/17) 4.1 Bcf/d (2019+ Sundown T82 T80 Dawson T78 Gla Swan T76 Groundbirch Mainline T74 to Alberta T72 93-P-1 R13 37#38Painted Pony Strategic Alliance Painted Pony actively markets the vast majority of natural gas volumes away from Station 2 index pricing and into more profitable sales points NYMEX 9% Condensate and NGLS 5% Total Expected Station 2 2% AECO 7% SUMAS 5% ■ ■ Townsend Facility anchor tenant with 20 year take-or-pay Low cost producer 1.6x Proved Developed Producing 2017 F&D Recycle Ratio¹ 6% decrease in per unit operating costs in 20172 ■ 2018 production guidance of between 348 Mmcfe/d - 360 Mmcfe/d1 Expecting 38% annual average daily production growth from 2017 to 2018 based entirely on growth through the drill-bit¹ ■ Reserves support multi-year drilling program and future growth ■ 2018 Production DAWN 6% Revenue by Source¹ Highly efficient drilling performance1 - Low well costs of ~$4 million per well Fixed Price Contracts 65% AltaGas PAINTED PONY ENERGY LTD. AltaGas 1 Painted Pony May 2018 Investor Presentation. 2 Painted Pony 2017 Annual Report 3 Painted Pony Q1 2018 Report See "forward-looking information" • - Top well performance of ~9 Bcfe estimated ultimate recovery per well Firm transportation in place to meet production growth targets - Exposure to Station 2 spot pricing reduced to ~2% of forecasted revenue1 ■ Solid financial position - March 31, 2018 net debt of $396.1 million (~40% of capacity)³ Meaningfully hedged production in Q2 - Q4 2018 (65%)¹ 14 year supply contract signed with Methanex currently delivering 10 Mmcf/d, increasing to 50 Mmcf/d by 2023 38#39Doubling the Townsend Gas Processing Complex Received regulatory approval for the doubling of the Townsend Facility to 396 Mmcf/d and to retrofit the existing 198 Mmcf/d shallow-cut Townsend Facility to a deep-cut facility at a future date Townsend phase 2 ■ Townsend Phase 2 will be constructed in two separate gas processing trains The first train (2A) is a 99 Mmcf/d shallow-cut natural gas processing facility located on the existing Townsend site - On-stream October 1, 2017 Fully contracted under a 20-year take or pay with Painted Pony The $125 million project was completed slightly ahead of schedule and approximately $5 million under budget The second train (2B) is under development with a target on-stream date of 2019/2020 AltaGas 1 Expectations as at August 1, 2018 See "forward-looking information" 39#40North Pine NGL Separation Facility to Serve Montney Producers ■ NGL facility to serve Montney producers in northeast British Columbia, near Fort St. John On-stream December 1, 2017 First train capable of producing up to 10,000 Bbls/d of C3+ processing capacity, with capacity of 6,000 Bbls/d of C5+ Two NGL supply pipelines will be constructed connecting the existing Alaska Highway truck terminal to the facility Well connected by rail to Canada's west coast including the Ridley Island Propane Export Terminal Backstopped by long-term supply agreements with Painted Pony for a portion of total capacity Expect further supply agreements with other producers The $120 million project was completed ahead of schedule and approximately $15 million under budget¹ Permitting in place for a second NGL separation train capable of processing up to 10,000 Bbls/d of propane plus NGL mix. Construction expected to follow after the completion of the first train, subject to sufficient commercial support from area producers AltaGas 1 Includes first train and two liquids supply lines 2 Expectations as at August 1, 2018 See "forward-looking information" 40#41AltaGas' Northeast B.C. and Energy Export Strategy Provides NEW market access for Western Canadian propane producers to Asia >40,000 bbl/d of C3 shipped to Asia RIPET Prince Rupert Blair Creek Townsend a AltaGas' propane export terminal at Ridley Island is poised to create a hub for key global markets to the west Significant shipping advantages vs. Gulf coast, providing producers with increased netbacks AltaGas Younger Liquids mix piped to NGL facility and rail terminal North Pine Fort St. John C4 and C5+ railed to Fort Saskatchewan • Fort Saskatchewan Edmonton • Historical C3 Prices ($USD/Gal) $3.00 $2.50 Propane railed to Tidewater $2.00 $1.50 Gas Processing Ferndale $1.00 LPG Export Terminal $0.50 LPG Export Terminal Under Construction $0.00 Truck Terminal ($0.50Jan-13 Jan-14 Jan-15 Jan-16 Jan-17 Jan-18 Liquids Pipelines (NGL mix and condensate) Japan Mont Belvieu Edmonton Montney (raw gas) See "forward-looking information" 41#42Ridley Island Propane Export Terminal First mover competitive advantage Expected to be Canada's first West Coast propane export terminal " ■ Construction is underway and is expected to be in service by Q1 2019 Facility designed for 40,000 bbls/d of export capacity Brownfield site includes existing world class marine jetty with deep water access, excellent railway access which enables the efficient loading of Very Large Gas Carriers that can access key global markets ~10 day to Asia vs. ~25 days from the U.S. Gulf Coast Astomos Energy Corporation to purchase 50% of the propane shipped from the facility ■ Currently have close to 75% of supply secured Expect at least 40% of the facility's throughput to be underpinned by tolling arrangements ■ Entered into a strategic joint venture with Royal Vopak who will take a 30 percent interest in the Terminal Estimated project cost of $450 - $500 million¹ AltaGas 1 Expectations as at August 1, 2018. Total project cost; ownership will be 70% ALA and 30% Royal Vopak See "forward-looking information" AltaGas 42#43Clear LPG Shipping Cost Advantage to Asia Japan/ Korea 1 Demand: Supply: 10 days Ocean Freight Cost Terminal Cost Rail Cost Ft. Saskatchewan Prince Rupert Rail Cost North America 1 Demand: Supply: Terminal Cost Ocean Freight Cost (Includes Canal Fee) Mt. Belvieu 25 days WCSB to Asia Costs (US$/Gal) WCSB Netbacks (US$/Gal) Japan Price less $0.30 to $0.40 Japan Price less $0.40 to $0.60 $0.10 -$0.20 Via RIPET Rail Terminal Included Via Gulf Coast $0.25-$0.30 Via RIPET Included Shipping Included Total Costs $0.30 -$0.40 $0.05 -$0.10 $0.10 -$0.20 $0.40 - $0.60 Via Gulf Coast RIPET Premium AltaGas 1 Shipping time as per Idemitsu Estimated based on public information See "forward-looking information" 43#44120 00 TEMP COMP 60% BASE CUBIC FEET 1982 00 TEMP COMP 60E BASE CUBIC FEET CL 175-250 SENSUS R-275 5 PSI MAOPAS OB-S TEM COM OFF BASE 373 15301681 ALTAGAS UTILITIES INC. 104681 107 SENSUS R-275 COMAY & PSI MAOP OB-G TER COMR 27 BASE AG-0173 15301676 ALTAGAS UTILITIES INC. 104676 Utilities TEMP COMP BASE CUBIC FEET CL 175-250 SENSUS R-275 SPSI MAOP GX PT PER M 02-STER COM SUE BASE 40-0373 15301682 ALTAGAS UTILITIES INC. 104682 109#45Michigan Growth Opportunity Marquette Connector Pipeline (MCP) ☐ ☐ Proposed pipeline that will connect the Great Lakes Gas Transmission pipeline to the Northern Gas pipeline in Marquette, Michigan Approximately 42 miles mainly with 20" diameter pipe Provides needed redundancy and additional supply options to SEMCO's ~35,000 customers in its service territory in Michigan's Western Upper Peninsula. It will also provide additional natural gas capacity to Michigan's Upper Peninsula to allow for growth Cost is estimated at US$135 - $140 million. Recovery on MCP is expected to be through a general base rate case Expected to meaningfully increase rate base Received approval of Act 9 application from the Michigan Public Service Commission in August 2017 to construct, own and operate the project Engineering and property acquisitions have begun and will continue throughout 2018, and construction to be completed in 2019 MCP is expected to be in service in Q4 2019 AltaGas Expectations as at August 1, 2018 See "forward-looking information" N Existing Pipelines Lake Superior USA Proposed Marquette Connector Pipeline Lake Michigan CANADA Lake Huron Detroit. 45#46Supportive Regulatory Environment for Regulated Gas Utilities Allowed ROE and Utility Location Equity Thickness Regulatory PM Pacific Northern Gas Ltd Rate case filed in November 2017 for 2018 and 2019 British Columbia 9.40% 1 45% AltaGas 8.50% Alberta 39% utilities Protected from weather related volatility through revenue stabilization adjustment account Operate under Performance-Based Regulation, 2018 - 2022 current term Cost recovery and return on rate base through revenue per customer formula Additional recovery and return on rate base through capital tracker program Heritage Gas 11% No regulatory lag; earn immediately on invested capital Nova Scotia 45% SEMCOENERGY Michigan 10.35% 49% CAS COMPANY ENSTAR Natural Gas Company Alaska 11.88% 51.80% Customer Retention Program approved in September 2016 results in a decrease in distribution rates for primarily commercial customers Use of projected test year for rate cases with 12 month limit to issue a rate order, eliminates/reduces regulatory lag Recovery of invested capital through the Main Replacement Program surcharge has reduced the need for frequent rate cases Last rate case filing completed in 2010; next case to be filed in 2019 In August 2017, received approval from the Michigan Public Service Commission for the Act 9 application for the Marquette Connector Pipeline Final order approving $5.8 million rate increase (including $5 million interim rates previously included in rates) issued on September 22. Final rates effective November 1, 2017 Next rate case to be filed in 2021 Cook Inlet Natural Gas STORAGE Alaska 12.55% 50.00% Rate case filing in April 2018 AltaGas 1 Approximate average between PNG and PNG NE See "forward-looking information" 46#47Washington Gas Regulatory Environment Allowed ROE and Utility Location Regulatory Washington Gas AWGL Company Washington Gas AWGL Company Virginia Equity Thickness Settlement reached based on revenue requirements - not ROE Maryland 9.5% 53.02% Washington Gas AWGL Company Washington D.C. 9.25% 55.7% Rate case was filed in June 2016 with a stipulation issued in April 2017; final Commission approval issued June 30 approving stipulation for $34 million annual revenue increase Expedited rate cases filed in July Rate case filed in May 2018 New 5 year plan for accelerated replacement to be filed in second half of 2018 for the 2019-2024 period Last rate case was filed in February 2016 with final rates approved in March 2017 Rate case to be submitted in 2020 New 5 year plan for accelerated replacement to be filed in 2019 for the 2020 - 2025 period - AltaGas See "forward-looking information" 47#4800 Power AltaGas FONTAINE#49Increasing optionality at Blythe Blythe Fully contracted with SCE through Q2 2020 Additional flexibility added with tie in to El Paso Gas supply in June 2017, and low- load turn down completed in July 2017 Large site capable of accommodating large scale solar or energy storage which can be combined with Blythe to offer in as a Bucket 2 resource New potential customers and options around re-contracting given the recent proliferation of Community Choice Aggregators Strengthening Resource Adequacy (RA) market, coupled with energy and ancillary services offerings also bode well post 2020. RIPON awarded RA contract for June - Sept and Oct - Dec, 2018 AltaGas See "forward-looking information" Generation increased by 98% in 2017 over 2016 MWh 12,000 10,000 8,000 6,000 4,000 2,000 0 1-Jan-16 1-Mar-16 1-May-16 Significant increase in generation following El Paso Gas tie-in and completion of the low load turn down 1-Jul-16 1-Sep-16 1-Nov-16 1-Jan-17 1-Mar-17 1-May-17 1-Jul-17 1-Sep-17 1-Nov-17 1-Jan-18 1-Mar-18 49#50Existing Permitted Gas Plants in California Have Embedded Value Which Can Grow Over Time High barriers to entry for new gas generation. Steel in the ground has significant value. New builds are difficult to permit, expensive to build and require long (~10 year) development time horizons. There are no new gas plants under construction in the densely populated San Francisco region. High demand drives premium pricing in these constrained load pockets - a key value driver for existing facilities in these regions. CAISO Local Constrained Areas¹ Tracy San Francisco Ripon Hanford Henrietta AltaGas Los Angeles • Pomona Blythe 1 Draft Manual 2016 Local Capacity Technical Study, California Independent System Operator, October 2014 See "forward-looking information" Tracy, Hanford, Henrietta and Ripon are all located in the San Joaquin Valley region east and south of San Francisco. Provide grid stability with flexible and fast ramping capacity that backstops renewables ■ Pomona is in the LA Basin load pocket Existing sites are all well suited for energy storage, resulting in lower brownfield development costs 50#51Duck Curve Becoming More Extreme Changing California Supply Mix Results in Market Imbalance and Instability Actual net-load and 3-hour ramps are about four years ahead of ISO's original estimate MW 28,000 Typical Spring Day1 2012 (actual) 2013 (actual) 26,000 24,000 22,000 20,000 18,000 2014 16,000 2015 2016 14,000 2018 2017 potential overgeneration 2019 2020 12,000 10,000 Actual net load of 6,964 MW on Feb. 18, 2018 0 12am 3am 6am 9am 12pm Hour 3pm 6pm 9pm increased ramp Actual 3-hour ramp of 14,432 MW on Feb. 23, 2018 Solutions are necessary to handle the deeper belly and steeper ramps of the duck curve including: ■ Battery storage - increase the effective participation by energy storage resources ■ Flexible fast ramping generation – invest in fast-responding resources like gas-fired generation that can follow sudden increases and decreases in demand 1 CAISO AltaGas See "forward-looking information" 51#52Energy Storage Pomona Energy Storage • • . 10 year Energy Storage Agreement (ESA) with Southern California Edison (SCE) for 20 MW energy storage at Pomona facility Resource adequacy capacity for four hour period, equivalent of 80 MWh of energy discharging capacity Commercial operations date: December 31, 2016 Other Battery Storage Opportunities • • • California's three largest utilities were mandated to procure 1,325 MW by 2020 • ~400 MWs are left to be procured by 2020 SCE, PG&E, and SDG&E to explore up to a combined 500 MW of additional distributed energy storage SCE to procure another 20 MW and LADWP to study 100 MW of cost effective energy storage resulting from Aliso Canyon Gas Storage integrity Additional 'Preferred Resources' RFPs are expected in 2018 that will include energy storage AltaGas will continue to leverage its existing sites and infrastructure as well as look for greenfield development opportunities Renewable Integration & Flexibility • California legislators continue to move towards reducing fossil fuel reliance which creates new energy storage procurement opportunities • CPUC is including energy storage in their resource planning to aid the integration of renewables Net load will need to be met by a combination of flexible resources, imports/exports, and curtailments AltaGas FONTAINE DON A AltaGas As at August 1, 2018 See "forward-looking information" 52 42#53Northwest B.C. Hydro - Stable Long-Term Financial Returns Forrest Kerr 195 MW fully contracted to 2074 McLymont Creek 66 MW fully contracted to 2075 Volcano Creek 16 MW fully contracted to 2074 ◉ ◉ ■ ■ Sold 35% of Northwest Hydro Facilities for $922 million, implying a 2017 EBITDA multiple of 27 times and a total value of $2.7 billion on a 100% basis 60 Year PPA with high quality credit (BC Hydro) - 100% indexed to B.C. CPI AltaGas as operator has excellent track record Minimal ongoing maintenance capital Very high capacity factors translates into low annual generation volatility See "forward-looking information" AltaGas $ Millions 600 500 400 300 200 100 0 NWH 60-year EBITDA: CPI indexing can deliver significant growth 5 Year 10Year 15 Year CPI 1% 20 Year 25 Year 30 Year CPI 1.5% 35 Year 40 Year 45 Year CPI 2% 50 Year 55 Year 60 Year CPI 2.5% 53#54Distributed Generation 222 MW 20 STATES + D.C. WITH DISTRIBUTED GENERATION ASSETS CALIFORNIA MINNESOTA 36 Projects in Service 25 MW of DC Capacity 24 Projects in Service 28 MW of DC Capacity AltaGas GEORGIA MARYLAND 53 Projects in Service 38 MW of DC Capacity 37 Projects in Service 35 MW of DC Capacity 54 54#55Key Sensitivities Key variables +/- $0.05 US/CAD Alta Gas Foreign Exchange 2018 Impact EBITDA ~$16 MM1 Frac Spread Key variables +/- $1/bbl 2018 Impact EBITDA ~$1 MM Natural Gas Volumes Key variables +/- 10% 2018 Impact EBITDA ~$16 MM AltaGas 1 Represents impact to 2H 2018 Expectations as at August 1, 2018 See "forward-looking information" 55