The Cascading Blackout: Why Wasn't the Power Outage Contained?

The sometimes conflicting goals of providing reliability, moderating power prices, deferring transmission investments, and avoiding the economic liabilities associated with third-party power transactions can cause transmission operators to take greater risks with the grid than they have in the past. This is according to a recent report titled "Cascading Blackout: Why Wasn't the Power Outage Contained?" This paper outlines the competitive pressures on existing transmission grid operations.

"If no contingencies occur, the transmission system usually operates smoothly; we maintain reliability, wholesale power prices are stable, and third-party generators gain access to markets," says Philip Mihlmester, Senior Vice President of ICF Consulting's Energy Practice. "However, if a contingency occurs under high-risk circum-stances, there is very little room for maneuverability," continues Mihlmester. "It's like driving a car at 30 mph and having a tire blow versus the same scenario while driving 100 mph. There is very little reaction time in the latter case."

So why was the blackout allowed to cascade throughout the Northeastern United States and portions of Canada, and not contained locally?

When a transmission line fails, the power flow must be redirected onto neighboring lines. Without sufficient reserve margin on those lines, they become overloaded -- causing a cascading effect -- shutting the system or a large portion of it down. A possible reason the cascade was not stopped is because neighboring transmission lines did not have sufficient reserve margin available due to heavy volumes of power flow. North America's power usage and the number of wholesale power transactions over the transmission lines have simply outgrown the existing transmission structure and the traditional reliability-based operational protocols. The transmission grid also suffers from declining investment over the past 25 years.

"Setting and enforcing consistent transmission reliability standards, as well as incentivizing additional capital investment in transmission, will help to prevent similar massive outages in the future," emphasizes Mihlmester.

To learn more about the competing pressures of grid operations, why containment failed, and recommendations on preventing future cascade occurrences, visit www.icfconsulting.com/cascade-containment.