Climate change questions and answers

Our transparent approach.

We endeavour to be transparent in our approach to our climate change plan and this includes giving open and honest answers to tough questions.

Having already delivered the world’s single largest climate change action to date when we closed our coal stations, we asked ourselves: “what’s next?” Our answer was to commit to doing more by setting an ambitious goal for our company as well as a goal to help drive decarbonization of the markets where we operate and to do so in a way that helps the economy.

We believe OPG is uniquely positioned to be a climate change leader because of our strong track record of innovation, efficient operations and project delivery.  Our diverse mix of generating assets, experience and expertise also set us apart.

We believe all good corporate citizens must have a credible climate change plan; something aspirational that rallies employees around a common goal – a goal that achieves tangible results for the environment and economy.

Aside from achieving our stated goals, we believe there’s tremendous potential to kick-start economic growth through upgrades and development of clean energy generation and by electrifying other sectors of the economy.

We also believe this can and must be done in a way that is mindful of customers.

Some of the key actions include:

  • Leading the development of small modular nuclear reactors;
  • Advancing electrification initiatives in the province;
  • Continuing to invest in our hydroelectric generation fleet;
  • Delivering the Darlington Nuclear Refurbishment on time and budget;
  • Focusing on adaptation and resiliency of our assets;
  • Exploring opportunities in non-hydro renewables and energy storage;
  • Investigating negative emissions technologies (for the removal and sequestration of carbon); and
  • Supporting nature-based solutions and biodiversity initiatives (to help provide offsets and support resiliency).

OPG’s targets align with Canada’s commitment to exceed its Paris Agreement target and to develop a plan to achieve net-zero emissions by 2050.

The goal of net-zero by 2050 is based on the science of the United Nations Intergovernmental Panel on Climate Change (IPCC) — a group of scientists that called for “rapid, far-reaching and unprecedented changes” to limit global temperature rise to 1.5 degrees Celsius in order to avoid a number of climate change impacts.

The Paris Agreement aims to strengthen the global response to the threat of climate change by keeping a global temperature rise this century well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius.

We also used our extensive modelling and forecasting expertise to project electricity demand, and combined that with our sound knowledge of emerging technologies, to develop an ambitious plan.

In addition to efficiently operating one of the largest clean power portfolios in North America, we delivered the world’s single largest climate change-specific action to-date when we closed all of our coal stations.

We’re continuously investing in upgrades to our renewable hydro generating stations. We have also recently expanded our renewable operations to the Untied States through acquisitions of two leading hydroelectric operators.

And we’re currently working on the Darlington Nuclear Refurbishment, which is one of Canada’s largest clean energy infrastructure projects. A refurbished Darlington will reduce carbon emissions by an estimated 297 million tonnes over its life.

We’re also leading the energy sector in using nature-based solutions to help tackle climate change and increase resiliency. This includes planting more than 8 million native trees and shrubs, creating over 120 acres of wetland, 210 acres of grassland and releasing more than 5 million Atlantic salmon into Lake Ontario and its tributaries – and we’re planning to do even more. 

We’re strengthening climate resiliency of our operations to ensure ongoing safety and reliability of generating facilities. These upgrades will help reduce the impacts of a changing climate on our host communities while helping decarbonize the economy.

We encourage you to read our Plan for a full outline of actions.

Our plan commits to protecting customers. We believe it’s possible to achieve further carbon reductions efficiently, especially by decarbonizing other sectors using Ontario’s clean power. 

That’s why we’ve been working on electrification initiatives like providing charging infrastructure to support the growth of electric vehicles.

We believe that leveraging the significant investment made into cleaning Ontario’s electricity sector to increase electrification makes the most economic sense and is the least costly path to decarbonization.

It means achieving an overall balance between emissions produced and emissions removed from the atmosphere.

In setting our ambitious company-specific goal for 2040, we knew there was more we can offer, and we wanted to play a leading role in helping jurisdictions reach their targets through electrification initiatives and innovative technologies like small modular nuclear reactor development. We have the experience, expertise and ability to help decarbonize economies and we want to share this experience with the world.

We believe SMRs are a real solution to climate change and Ontario is uniquely positioned to lead the world in their development.

OPG is the first utility in the world to take an ownership stake in a Micro Modular ReactorTM, through a joint venture with Global First Power and Ultra Safe Nuclear Corporation. This pioneering SMR project at Chalk River Laboratories can serve as a model for future SMR projects in Ontario and beyond.

We’re also working with three grid-scale SMR technology developers – GE Hitachi, Terrestrial Energy, and X-energy – to advance engineering and design work as part of efforts to identify options for future deployment.

Most recently, we announced the resumption of planning activities for a new nuclear build at the Darlington site with the goal of hosting a grid-size SMR by as early as 2028, pending regulatory approvals and licensing.

SMRs offer the benefits of traditional nuclear reactors – they are able to generate reliable electricity with near zero carbon emissions, and they operate around the clock under all weather conditions.

Unlike traditional reactors, they will be smaller — typically with a generating capacity under 300 megawatts — and easier to build and operate.  This means they can help power cities or remote communities that currently run on diesel generators, or even industrial operations like mining sites.

Electrification refers to the process of switching parts of our economy that currently use fossil fuels (such as heating or transportation) to use electricity instead.

Because Ontario generates most of its electricity from nuclear and hydroelectric sources, the carbon intensity of our electricity sector is very low — about 40 grams per kilowatt-hour in 2022. By comparison, California’s carbon intensity is more than seven times this amount and Germany is 12 times greater. The more of the economy we can get running on electricity, the lower our carbon emissions will be.

Now more than 30% of Ontario’s carbon emissions come from transportation. Powering cars, trucks, trains, boats and buses with clean electricity, rather than gas or diesel, will make a very significant impact.

OPG is fortunate in that we have a range of technologies and initiatives to help us achieve our net-zero by 2040 goal.

This includes developing SMRs, completing the Darlington Refurbishment, electrifying transportation, and upgrading our hydroelectric stations. We’re also exploring negative emission technologies and nature-based solutions.

We acknowledge our goal is ambitious but our Plan is designed to be flexible and evolve over time.  We also believe that as the world advances to the realities of a changing climate, so too will solutions and policies.

Although it sounds counterintuitive, natural gas generation will play an important role in transitioning away from fossil fuels.

Renewable sources like solar and wind are intermittent by nature so they require a backup source that can be dispatched to meet ever-changing electricity demands in the market.

Having flexible natural gas to backup renewables, provides the system stability and reliability needed to continue to evolve.

We will aim to operate gas facilities as carbon efficiently as possible, including exploring new technologies where economic and feasible.



In Ontario, OPG owns and operates 66 hydro stations that produce clean, renewable, reliable low-cost power. More than half are over 80 years old, providing value for generations. Every year, they produce over 30 billion kilowatt-hours of power - more than one-third of OPG’s electricity production.

OPG is reinvesting in our hydroelectric fleet to sustain and, where possible, grow generation from these valuable assets. Key projects are currently underway at our Calabogie, Sir Adam Beck and Ranney Falls generating stations.

Refurbishing the Darlington Nuclear GS is currently one of Canada’s largest clean energy infrastructure projects and is critical to our climate plan. The four-unit station generates over 20% of Ontario’s electricity, or enough energy to power two million homes.

An independent report prepared by Intrinsik Environmental Sciences noted the continued operation of a refurbished Darlington Nuclear to 2055 would equal removing two million cars per year from Ontario’s roads by avoiding significant carbon gas emissions.

Securing our nuclear power supply is key to keeping Ontario as one of the cleanest jurisdictions in the world, by providing reliable baseload power 24/7/365 with near zero carbon emissions.

OPG continually invests in strengthening our generating assets and operations against climate impacts.  This is critical to adaptation. We also reduce the impacts on our host communities by investing in nature-based protection measures like developing wetlands to help mitigate flooding.

Beyond updating traditional technologies and processes, we will continue to integrate climate science and modelling into our investment decision and engineering processes, when considering future design and asset upgrades.

We believe getting ahead of Ontario’s climate risks will strengthen the electricity grid’s resiliency, which is the foundation for decarbonizing the broader economy.

The intermittent nature of renewables like wind and solar creates reliability challenges for the system, where the supply of energy and demand must be continually balanced.  

These challenges can be partially overcome by pairing renewable sources with energy storage technologies to increase reliability, especially during periods of peak demand. 

OPG sees energy storage as an important part of meeting future system needs.  We have considerable expertise in solar and storage development, having recently converted the former coal-fired Nanticoke Generating Station site into a 44 MW solar facility in partnership with Six Nations of the Grand River and the Mississaugas of the Credit First Nation.

We also helped to develop a solar and storage micro grid for an off-grid First Nations community, and two other energy storage facilities that manage industrial companies’ peak energy consumption.

As part of our research, we looked at a number of Canadian and US energy companies for public disclosure of net-zero goals, targets, and activities. At the time of release, we are aware of companies with net-zero related disclosures, most of which are linked to 2050 targets.

No companies specifically define how they will reduce emissions to zero. We believe OPG’s emphasis on transparency and our willingness to spell out our actions and possible paths forward set us apart in this regard.

Download full plan
Download PDF (6MB) - English
Report Highlights:
  • Introduction
  • Climate change goals
  • Climate change solutions
  • Climate action plan

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