A reckoning for OPG: Part 1

I previously posted this work as a single long substack piece 

Summary

Ontario Power Generation’s newly refurbished Darlington nuclear station is underperforming at a moment when the utility is asking ratepayers and government to support even larger nuclear commitments. With only one of four Darlington reactors operating this August, the situation raises questions about OPG’s operational reliability, rate-setting incentives, and broader role as Ontario’s publicly owned generator. This report argues that today’s concerns echo the conditions that led to the breakup of Ontario Hydro: escalating costs, weakening performance, opaque decision-making, and a public utility increasingly managed as a profit-seeking business rather than as a provider of power at cost. The immediate outage issue may prove explainable, but unless OPG is transparent about Darlington’s performance and the financial incentives embedded in its regulated rates, the political and public narrative around expensive, unreliable nuclear power could again become dangerous for Ontario’s electricity system. 

Key findings 

• Darlington’s post-refurbishment performance is raising reliability concerns, with only one of four reactors operating during August despite the project’s recent completion.
• OPG’s public communications have not adequately explained the recent outages, leaving room for speculation about whether they reflect technical problems, maintenance timing, financial incentives, or some combination of these factors.
• The utility’s regulated rate structure may reward higher costs, lower production forecasts, and retained earnings growth, creating incentives that do not align neatly with ratepayer interests.
• Current concerns echo the late Ontario Hydro period, when nuclear cost overruns, weakening performance, and governance choices damaged public and political confidence in the utility.
• As OPG pursues small modular reactors, Pickering refurbishment, and possible new nuclear development, stronger transparency and accountability are needed before Ontario commits to further large-scale nuclear spending.

These findings point to a larger question than whether Darlington is simply having a bad month. The issue is whether Ontario’s publicly owned generator is still being governed, regulated, and explained to the public in a way that serves ratepayers first. That question begins with the immediate facts at Darlington, but it quickly leads back to the history Ontario has already lived through once: a nuclear-heavy public utility whose cost, performance, and institutional purpose became politically unsustainable.

Introduction

Ontario Power Generation (OPG) was celebrated for completing the refurbishment of its Darlington nuclear generating station (DNGS) early this year, but today only one of the four reactors at the facility is operating. Two units dropped out of service in the first few days of August.[1] OPG is in the process of spending billions of dollars at building first-of-a-kind (FOAK) small modular reactors (SMR’s), planning to spend even more on the refurbishment of the older, smaller, Pickering Nuclear Generation Station, planning for what could become the largest nuclear generating station on earth, and sharply escalating pricing to consumers. The apparent failures at reactors in its touted DNGS refurbishment should raise alarm bells about OPG’s performance and a re-examination of its purpose.

A 25% summer capacity factor for a nuclear site is historically terrible, although it may have extenuating circumstances. OPG’s other nuclear generating station, Pickering (PNGS), is set to be taken out of service (for a long-duration refurbishment) at the end of September. It is possible OPG moved up some maintenance tasks to occur while PNGS was being productive, although there was no indication in the system operator’s (IESO) reporting that the two recent outages were planned. It is possible that OPG is tanking their 2026 results to avoid consumers benefitting from the very high profits reported in recent years – and I’ll explain later that it is a certainty the government has acted to prevent this. The reality is likely a combination of all three things – an unexpected trip causing an outage that gets expanded to address other issues because the loss of revenue would best be taken sooner. Speculation need not to be invited – OPG could just inform the public when units go offline- so the only certainty is that only one of four newly refurbished reactors is generating power this August.

On February 2nd of this year OPG announced, “Darlington Refurbishment construction completed ahead of schedule, under budget”.[i][1]

The latest OPG financial reporting[2], for the second quarter of 2026, notes the refurbishment period of unit 4 (G4) ended March 12th. Since that date the DNGS has had all 4 units producing power for 18 days. Unit 4, the final unit to return from the lengthy life-extension, has operated on only half of the days since its feted return to service.

To understand the danger DNGS’s current performance presents to Ontario, and its nuclear industry in particular, it will be helpful to revisit:

1. the dissolution of Ontario Hydro in the 1990’s;
2. the changing position of Ontario Power Generation as it emerged as the public generator in a so-called market era, and emergence of Bruce Power;
3. the financial drivers of OPG’s rates

Each of these three subjects deserves a broader look than the summaries I will provide, but the short reviews may suffice to show my concerns with OPG’s performance, rates, and viability as an ongoing entity.

next part: The Wreck of the Ontario Hydro