Hydro One (HRNNF) chosen to build Red Lake transmission line with First Nations

Rhea-AI Filing Summary

Hydro One Limited filed a Form 6-K highlighting that Ontario’s Energy and Mines Minister has directed the Ontario Energy Board to designate Hydro One Networks Inc. to develop and construct the Red Lake Transmission Line in northwest Ontario.

The proposed priority project is a new double-circuit 230-kilovolt transmission line from Dryden Transformer Station to Ear Falls Transformer Station, continuing to Red Lake Switching Station, and is expected to be in service by the early 2030s. Once built, it is expected to add about 400 megawatts of electricity capacity in northwest Ontario, nearly quadrupling existing capacity and strengthening regional reliability for newly connected northern remote communities and the broader region.

Through Hydro One’s First Nation Equity Partnership Model, proximate First Nations will have the opportunity to invest in a 50 per cent equity stake in the transmission line component of the project and collaborate on planning, development and construction. Ontario states that its plan related to this project will unlock more than 5,800 jobs and $830 million in economic potential. The filing also reiterates Hydro One’s 2025 profile, including $39.7 billion in assets and $9 billion in annual revenues, and includes standard forward-looking information cautions.

Insights

Infrastructure & utilities analyst

Ontario designates Hydro One for a major grid expansion with First Nations equity participation.

The designation to develop the Red Lake Transmission Line confirms Hydro One as the utility lead on a priority 230-kilovolt project in northwest Ontario. The line is expected to add about 400 megawatts of regional capacity, nearly quadrupling existing levels and supporting reliability for remote communities.

A notable feature is the First Nation Equity Partnership Model, under which proximate First Nations can invest in a 50 per cent equity stake in the transmission line component and co-develop the project. Ontario’s description of more than 5,800 jobs and $830 million in economic potential underscores broader regional stakes, though the filing does not break out Hydro One’s specific financial returns, leaving the economic impact on the company to future regulatory and project details.

Key Figures

Assets: $39.7 billion Annual revenues: $9 billion Capital investment: $3.4 billion +5 more

8 metrics

Assets $39.7 billion Assets as at December 31, 2025

Annual revenues $9 billion Annual revenues in 2025

Capital investment $3.4 billion Invested in transmission and distribution networks in 2025

Goods and services purchased $3.0 billion Goods and services bought in 2025

New capacity 400 megawatts Additional capacity expected from Red Lake Transmission Line

Economic potential $830 million Economic potential Ontario associates with its plan

Jobs associated 5,800 jobs Jobs Ontario links to its plan for the project

Customer base 1.5 million customers Electricity transmission and distribution customers

Key Terms

First Nation Equity Partnership Model, double-circuit 230-kilovolt transmission line, forward-looking information, safe harbour, +1 more

5 terms

First Nation Equity Partnership Model financial

"Through Hydro One’s First Nation Equity Partnership Model, proximate First Nations will have the opportunity to invest"

double-circuit 230-kilovolt transmission line technical

"The proposed priority project consists of a new double-circuit 230-kilovolt transmission line"

forward-looking information regulatory

"This press release may contain “forward-looking information” within the meaning of applicable Canadian securities laws"

Forward-looking information are predictions, plans, estimates or expectations about a company’s future performance, results or events, such as sales forecasts, project timelines, or anticipated costs. It matters to investors because these statements guide expectations but rely on assumptions and uncertain factors—like a weather forecast for a business—so investors should treat them as informed guesses rather than guarantees and consider the risks and possible changes behind the numbers.

safe harbour regulatory

"Statements containing forward-looking information are made pursuant to the “safe harbour” provisions of applicable Canadian and U.S. securities laws"

medium term notes financial

"Hydro One Limited’s common shares are listed on the TSX and certain of Hydro One Inc.’s medium term notes are listed on the NYSE"

Medium term notes are debt securities companies or governments sell to borrow money for a few years—generally from about two to ten years—paying regular interest and returning your principal at maturity. Think of them like an IOU with a set length and interest schedule that investors can buy to earn income; they matter because their credit quality, interest rate type (fixed or floating) and maturity affect how much return and risk an investor takes on compared with short-term bills or long-term bonds.

Form 6-K: How Foreign Companies Report to the SEC →

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

Pursuant to Rule 13a-16 or 15d-16

under the Securities Exchange Act of 1934

For the month of: April 2026

Commission File Number: 333-225519-01

HYDRO ONE LIMITED

(Translation of Registrant’s name into English)

483 Bay Street, South Tower, 8th Floor, Toronto Ontario M5G 2P5 Canada

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☐    Form 40-F ☒

SIGNATURE

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, thereunto duly authorized.

HYDRO ONE LIMITED

/s/ Cassidy McFarlane

Name: Cassidy McFarlane

Title: General Counsel

Date: April 23, 2026

EXHIBIT INDEX

99.1 News Release dated April 23, 2026

Exhibit 99.1

Ontario designates Hydro One to invest in the Red Lake Transmission Line

The proposed project will be developed in partnership with First Nations, add capacity and strengthen regional reliability in the northwest

Thunder Bay, Ont., April 23, 2026 – Today, Energy and Mines Minister Stephen Lecce directed the Ontario Energy Board to designate Hydro One Networks Inc. (Hydro One) to develop and construct the Red Lake Transmission Line in northwest Ontario, north of Dryden. The proposed priority project consists of a new double-circuit 230-kilovolt transmission line that will run from Dryden Transformer Station (TS) north to Ear Falls TS, including associated station facilities and will continue on to connect to Red Lake Switching Station. The project is expected to be in service by the early 2030s.

Once built, the Red Lake Transmission Line is expected to add about 400 megawatts of electricity in northwest Ontario, nearly quadrupling existing capacity. The project is also expected to strengthen regional reliability and reinforce the grid for newly connected northern remote communities and the broader region.

Through Hydro One’s First Nation Equity Partnership Model, proximate First Nations will have the opportunity to invest in a 50 per cent equity stake in the transmission line component of the project. Together, Hydro One and the proximate First Nations will collaborate on the planning, development and construction of the line.

Quotes

“Ontario’s long-term growth depends on strong and reliable electricity infrastructure. The Red Lake Transmission Line will support northern reliability, enable growth and help power communities north of Dryden,” said Ryan Docherty, Executive Vice President, Capital Portfolio Delivery, Hydro One. “We continue to work with First Nations as partners to develop these projects, ensuring they reflect local priorities and support economic reconciliation. We thank the government for its continued trust as we invest in a strong and secure electricity system for the future.”

“Our government is on a mission to grow our economy by generating more reliable hydro power in the North and electrifying one of Ontario’s most mineral rich regions with a new transmission line,” said Stephen Lecce, Minister of Energy and Mines. “We are accelerating the transmission line to power new mines, strengthen energy security and create good jobs. Ontario’s plan will unlock more than 5,800 good-paying jobs and unlock $830 million in economic potential, all delivered in true partnership with First Nations.”

“Eagle Lake First Nation strongly believes that projects taking place within our traditional territory must be done in collaboration and partnership with our Nation. Doing so ensures that we can fulfil our duty as stewards of the land and develop projects in a way that respects our traditional laws, teachings and values,” said Chief Bernadette Wabange, Eagle Lake First Nation. “This translates into projects that do not compromise environmental protections for economic development and protect our traditional lands for future generations. We are proud to work in partnership with Hydro One and the other partner First Nations to advance this project in a good and respectful way.”

“This project will support regional growth and provide long-term energy capacity to the recently connected First Nations north of Red Lake,” said Chief Clifford Bull, Lac Seul First Nation. “Lac Seul First Nation applauds Ontario for prioritizing this project and recognizing the value of First Nation partnerships to move it forward in a good way.”

“Wabauskang First Nation is located along the route of this transmission project, and our community must be meaningfully involved at every stage,” said Chief Bill Petiquan, Wabauskang First Nation. “Ontario has taken an important step by engaging us early as a key partner. We are ready to work collaboratively to ensure the project brings economic opportunities for our people while protecting our lands, waters and values.”

“Wabigoon Lake Ojibway Nation has a strong track record of building business partnerships that deliver real benefits for our members. Our partnership with Hydro One and other regional First Nations on this new transmission line marks our second major transmission project together, and we are proud to continue growing these strategic relationships,” said Chief Clayton Wetelainen, Wabigoon Lake Ojibway Nation. “We plan to apply the lessons learned from our previous transmission project to make this the best one yet for First Nations – creating greater benefits and opportunities for our Nation while supporting long-term regional prosperity. This partnership reflects our identity as Ojibway people, where economic opportunity and cultural strength go hand in hand as we build a better future for the next generations.”

- 30 -

Hydro One Limited (TSX: H)

Hydro One Limited, through its wholly-owned subsidiaries, is Ontario’s largest electricity transmission and distribution provider with 1.5 million valued customers, $39.7 billion in assets as at December 31, 2025, and annual revenues in 2025 of $9 billion.

Our team of 9,600 skilled and dedicated employees proudly build and maintain a safe and reliable electricity system which is essential to supporting strong and successful communities. In 2025, Hydro One invested $3.4 billion in its transmission and distribution networks, and supported the economy through buying $3.0 billion of goods and services.

We are committed to the communities where we live and work through community investment, sustainability and diversity initiatives.

Hydro One Limited’s common shares are listed on the TSX and certain of Hydro One Inc.’s medium term notes are listed on the NYSE. Additional information can be accessed at www.hydroone.com, www.sedarplus.com or www.sec.gov.

For more information about everything Hydro One, please visit www.hydroone.com where you can find additional information including links to securities filings, historical financial reports, and information about the Company’s governance practices, corporate social responsibility, customer solutions, and further information about its business.

Forward-looking statements and information:

This press release may contain “forward-looking information” within the meaning of applicable Canadian securities laws and “forward-looking statements” within the meaning of applicable U.S. securities laws (collectively, “forward-looking information”). Statements containing forward-looking information are made pursuant to the “safe harbour” provisions of applicable Canadian and U.S. securities laws. Words such as “expect”, “anticipate”, “intend”, “attempt”, “may”, “plan”, “will”, “can”, “believe”, “seek”, “estimate”, and variations of such words and similar expressions are intended to identify such forward-looking information. These statements are not guarantees of future performance or actions and involve assumptions and risks and uncertainties that are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed, implied or forecasted in such forward-looking information. Some of the factors that could cause actual results or outcomes to differ materially from the results expressed, implied or forecasted by such forward-looking information, including some of the assumptions used in making such statements, are discussed more fully in Hydro One’s filings with the securities regulatory authorities in Canada, which are available on SEDAR+ at www.sedarplus.com. Hydro One does not intend, and it disclaims any obligation, to update any forward-looking information, except as required by law.

FAQ

What did Hydro One (HRNNF) announce about the Red Lake Transmission Line?

Hydro One reported that Ontario’s Energy and Mines Minister directed the Ontario Energy Board to designate Hydro One Networks Inc. to develop and construct the Red Lake Transmission Line in northwest Ontario, positioning the company to lead a major new 230-kilovolt transmission project.

How much new capacity will Hydro One’s Red Lake Transmission Line add?

Once built, the Red Lake Transmission Line is expected to add about 400 megawatts of electricity capacity in northwest Ontario. This nearly quadruples existing capacity in the region and is intended to strengthen reliability for newly connected northern remote communities and surrounding areas.

How are First Nations involved in Hydro One’s Red Lake project?

Through Hydro One’s First Nation Equity Partnership Model, proximate First Nations will have the opportunity to invest in a 50 per cent equity stake in the transmission line component. They will collaborate with Hydro One on planning, development and construction, aligning economic benefits with local stewardship priorities.

What economic impact does Ontario associate with the Red Lake Transmission Line?

Ontario indicates that its plan related to the Red Lake Transmission Line will unlock more than 5,800 good-paying jobs and $830 million in economic potential. These figures reflect broader regional economic effects tied to new mines, energy security and long-term infrastructure development in the north.

What are Hydro One’s key 2025 financial figures mentioned in the 6-K?

Hydro One highlights that it had $39.7 billion in assets as at December 31, 2025, and annual revenues of $9 billion in 2025. The company invested $3.4 billion in its transmission and distribution networks and purchased $3.0 billion of goods and services during 2025.

How large is Hydro One’s customer base and workforce according to the filing?

Hydro One states it is Ontario’s largest electricity transmission and distribution provider, serving 1.5 million customers. The company reports a workforce of 9,600 skilled and dedicated employees who build and maintain the electricity system across its service territory.

Filing Exhibits & Attachments

1 document

Press Releases

• EX-99.1 EX-99.1 11.2 KB