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December 5, 2025

Independent Electricity System Operator (IESO)

The Independent Electricity System Operator is responsible for operating the electricity market and directing the operation of the bulk electrical system in Ontario.
IESO
IESO Tweaks Modeling for Outage Management

IESO is changing how it projects renewable generation output and its accounting for imports and planned loads in the forecasts it uses to manage generator and transmission outages.

NERC
NERC Finds Growing Shortfall Risk in Canada
The Canadian supplement to NERC's Interregional Transfer Capability Study recommended 14 GW of additional transfer capability in the country, mostly in Quebec.
Yes Energy
Ontario Introducing Nodal Market May 1
IESO is scheduled to launch its new nodal market May 1, a change it says will save Ontario $700 million over the next decade through reduced out-of-market payments and increased efficiency.
© RTO Insider
What to Know About IESO
IESO has 37.2 GW of installed capacity and 18,640 miles of transmission, both ranked seventh among the nine organized markets in the U.S. and Canada.
IESO
FAQs: Ontario’s Shift to a Nodal Market
Yes Energy's Emily Merchant provides answers to some frequently asked questions about IESO's new nodal market.
© RTO Insider LLC 
Ontario Premier Ford Slaps 25% Tariffs on Power Exports to US
Ontario Premier Doug Ford followed through on a threat to implement a 25% tariff on electricity exports to the US, a response to President Trump's own 10% tariff that went into effect last week.
© RTO Insider LLC
Overheard at CERAWeek 2024
CERAWeek 2024 by S&P Global was supposed to explore “strategies for a multidimensional, multispeed and multifuel energy transition.” Instead, the buzz was all about data centers and artificial intelligence.
© RTO Insider LLC
Panelists Say Focus, Fun Equally Important to GridEx
Held every two years, the GridEx conference helps electric utilities and other stakeholders test and improve their security incident response plans.
NERC
Stakeholders Respond to ERO Budget Drafts
Industry stakeholders expressed concern about the ERO's rising budgets and assessments in comments last week.
NERC
NPCC Warns of Tight Summer Margins in Ontario
Canada’s Ontario and Maritimes provinces may have to rely on energy imports and operating procedures to meet energy needs this summer, the NPCC said.

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