Hydro One Limited — Proxy Solicitation & Information Statement 2023

May 3, 2023

Notice of 2023 Annual Meeting of Shareholders and Availability of Proxy Materials

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Hydro One Limited ( Hydro One or the company ) is providing you with electronic notice and access to its management information circular (the circular ) for the company’s 2023 annual meeting of shareholders (the meeting ) instead of mailing out paper copies, as permitted by applicable Canadian securities laws. Electronic delivery is environmentally friendly and saves money. If you have questions about notice and access or how to vote your shares or access the meeting, please call 1-844-916-0609 toll-free within North America for service in English, or 1-844-973-0593 toll-free within North America for service in French or 1-303-562-9305 (English) / 1-303-562-9306 (French) (outside North America). This notice provides details of the date, time and means of accessing the meeting, including matters to be voted on at the meeting. It is not a form of proxy or voting instruction form and cannot be used to vote your shares.

Accompanying this notice is a form of proxy or voting instruction form that you will need to vote by proxy and/or to access the virtual meeting using your unique 16-digit control number. All shareholders are reminded to review the circular before voting.

Notice is hereby given that an annual meeting of shareholders of Hydro One will be held:

When:

Friday, June 2, 2023 9:30 a.m. (Eastern Time)

Where - Hybrid Meeting:

Live audio webcast online: www.virualshareholder meeting.com/HRNNF2023

In person: Lakehead University, Advanced Technology & Academic Centre, 955 Oliver Rd, Thunder Bay, ON, P7B 5E1*

• Subject to public health directives

The purpose of the meeting is to:

• Receive Hydro One’s 2022 audited consolidated financial statements together with the report of the external auditors on those statements

• Elect directors to the board for the ensuing year

• Appoint KPMG LLP as external auditors for the ensuing year and authorize the directors to fix their remuneration

• Consider a say on executive pay shareholder resolution

• Transact any other business as may properly come before the meeting

For further information on the items of business, see “Items of Business” starting on page 3 of the accompanying circular.

How can I participate in the meeting?

The company is conducting a hybrid annual meeting of shareholders that will allow registered shareholders and duly appointed proxyholders (including non-registered ( beneficial ) shareholders who have properly appointed themselves as proxyholder) to participate both online and in person.

Should you choose to attend and participate online, you will be able to access the meeting using an internet connected device such as a laptop, computer, tablet or mobile phone. The online meeting platform will be supported across browsers and devices that are running the most updated version of the applicable software plugins.

It is important that you review the detailed information on how shareholders can participate in and vote at the meeting starting on page 7 of the accompanying circular. The procedures are different for registered and non-registered shareholders. You should carefully review this information well in advance of the meeting.

Only registered shareholders and duly appointed proxyholders (including non-registered ( beneficial ) shareholders who have properly appointed themselves as proxyholder) will be entitled to attend, participate in, ask questions and vote at the meeting, whether in person or online, all in ‘real time’. Non-registered ( beneficial ) shareholders who do not duly appoint themselves as proxyholder and registered guests may attend the meeting, whether online or in person, but will not be able to participate in, ask questions, or vote at the meeting.

Registered shareholders and duly appointed proxyholders participating in the meeting online must remain connected to the internet at all times during the meeting in order to vote when balloting commences. It is the registered shareholder’s and duly appointed proxyholder’s responsibility to ensure internet connectivity for the duration of the meeting. Shareholders are encouraged to vote in advance using any of the methods below.

How do I get an electronic copy of the circular?

• Electronic copies of the circular may be accessed online on Hydro One’s website at www.hydroone.com/investor relations/agm or under the Hydro One Limited profile on the System for Electronic Document Analysis and Retrieval ( SEDAR ) at www.sedar.com. You can also access our 2022 annual report (the annual report ) containing our financial statements and related management’s discussion and analysis for the year ended December 31, 2022 in the same manner.

How do I get a paper copy of the circular?

In addition to being able to quickly view or print the circular and/or annual report online at our website, shareholders can request that a paper copy of either or both documents be sent by regular postal delivery, free of charge. Requests may be made by phone, email or online using the methods below.

Shareholders with a 16-digit control number:

By phone: Toll-free at 1-877-907-7643 (within North America) or 1-303-562-9305 (English)/1-303-562-9306 (French) (outside of North America)

Shareholders without a 16-digit control number:

By phone: Toll-free at 1-844-916-0609 (English) or 1-844-973-0593 (French) (within North America) or 1-303-562-9305 (English)/1-303-562-9306 (French) (outside of North America)

Online: www.proxyvote.com (enter the control number located on the voting instruction form).

To receive the meeting materials prior to the proxy deadline (as defined below) for the meeting and before the meeting, you should make your request before 5:00 p.m. (Eastern Time) on May 23, 2023. For requests received on or after the date of the meeting, a paper copy will be mailed to you within 10 calendar days after receiving your request. The meeting materials will also remain available at www.proxyvote.com for a period of at least one year after filing on SEDAR.

How do I vote my shares?

Shareholders attending the shareholders meeting (including beneficial shareholders who have properly appointed themselves as proxyholder) can vote online or in person at the meeting. Detailed information on how shareholders can participate in and vote at the meeting starts on page 6 of the accompanying circular. This includes information on how beneficial shareholders can appoint themselves as proxyholder. The procedures are different for registered and non-registered shareholders, so you should review this information carefully well in advance of the meeting. Registered guests may attend the meeting online or in person but will not be able to participate in, ask questions, or vote at the meeting.

You may also vote your shares in advance by proxy in any of the following ways. You will need the control number contained in the accompanying form of proxy or voting instruction form in order to vote.

Internet voting	For all shareholders, registered and non-registered (benefcial), go towww.proxyvote.comor follow the instruction provided by your bank or broker
Telephone voting	Call the toll-free number shown on the form of proxy or voting instruction form
Voting by mail ordelivery	Complete the form of proxy or voting instruction form and return it in thepre-paid envelope provided

To be valid, shareholders must vote or appoint their proxyholder using one of the above applicable methods, by no later than 9:30 a.m. (Eastern Time) on May 31, 2023 (the proxy deadline ) or, if the meeting is postponed or adjourned, no later than 48 hours (not including Saturdays, Sundays or statutory holidays in Ontario) prior to the postponed or adjourned meeting. Non-registered shareholders should return their voting instruction forms to their intermediary using one of the above methods so it is received at least one business day in advance of the proxy deadline and should consult the instructions on their voting instruction forms.

Hydro One reserves the right to accept late proxies and to waive the proxy deadline, with or without notice, but is under no obligation to accept or reject any particular late proxy.

The contents of the circular and the sending thereof to the shareholders have been approved by Hydro One’s board of directors.

DATED at Toronto, Ontario this 12[th] day of April, 2023

By order of the board of directors

PLEASE REVIEW THE CIRCULAR PRIOR TO VOTING

Louise Meegan Interim Corporate Secretary