The tree limb that fixed the electric grid

On Aug. 14, 2003, in a rural area of northern Ohio, a high-voltage transmission line sagging in the summer heat brushed against a tree limb and shut down. Over the next several hours, three other lines in the area, now under increased load, also sagged into overgrown trees and switched off.

These faults – coupled with a series of equipment and software failures, as well as human error – triggered a series of shutdowns that cascaded from state to state.

By the time it was over, 55 million customers in eight states and Ontario were left without power. For some, the outage would last for two days. The Northeast Blackout of 2003 would become an historic event – one of the most widespread electric failures of all time.

Transmission and Delivery: What’s the difference?
In terms of the electric grid, there are two types of systems that carry electricity from the generating stations that produce energy, to our homes where that energy is put to use.

Transmission: The transmission system is like our national highway network – the interstates of the electric grid – carrying high-voltage supplies of electricity over long distances. Tall steel towers typically are part of the transmission system.

Distribution: If ‘transmission’ lines are the grid’s highways, ‘distribution’ is the local street map, carrying electricity from our switching stations and substations to our customers’ homes and businesses. The electric wires carried along streets and through neighborhoods atop wooden poles are characteristic of the distribution system.

The massive outage also became the catalyst for more than a decade’s worth of transmission infrastructure upgrades across the footprint of PJM Interconnection – much of it right here in New Jersey – that has created a more reliable, more resilient electric grid and, at the same time, helped reshape the business of PSE&G.

Our journey began in earnest approximately 10 years ago, in 2007. The need for many of our large projects – North Central Reliability, Burlington-Camden, Susquehanna-Roseland and Mickleton-Gloucester-Camden, for example – was identified by PJM, the independent planner and operator of the transmission grid in 13 states including New Jersey, to address thermal or voltage issues on the system, thereby maintaining grid reliability. The 2003 blackout exposed a number of weak spots in the nation’s electric transmission system, including old lines that were prone to fail under heavy loads and voltage stability concerns. These projects were designed to address those needs.

The blackout also revealed other holes in the grid’s reliability safeguards – from technology to training to vegetation management. At PSEG, we have adopted many of the post-blackout regulatory recommendations and improvements.

During the past decade, PSE&G has invested $13.7 billion in electric system upgrades. Most of that investment – approximately $9.5 billion – was spent to modernize and upgrade transmission facilities.

The result: PSE&G’s reliability ranks among the top 10 percent of the nation’s biggest utilities.

PSE&G has made tremendous progress over the past decade. While we have addressed many identified reliability concerns, and will continue to address as they arise, our current focus is largely on replacing aging infrastructure and ensuring there is sufficient resiliency built into the system.

One example: The recently approved $739 million Metuchen-Trenton-Burlington (MTB) project, approved by PJM in February, which calls for replacing and upgrading the Metuchen-to-Trenton and Trenton-to-Burlington 138kV circuits to 230kV circuits.

And two weeks ago, we received approval for replacement of Newark Switch, a significant reliability and aging infrastructure project not far from our headquarters.

There is still much more to be done.

As bad as the 2003 blackout was for New Jersey, Superstorm Sandy in 2012 was worse – cutting power to more than 90 percent of our customers, some for more than a week. Our $1.2 billion Energy Strong program was created to address many of the weaknesses in our energy network – in particular, raising substations out of reach of Sandy-like floodwaters. We expect to request an extension of Energy Strong in the coming year, with a focus on making sure that our system is resilient enough to withstand another storm of this type. Our resiliency investments cover both the transmission and the distribution system.

Just as we’re replacing aging parts of our electric system, our gas system modernization program is replacing aging cast-iron and steel gas mains that are prone to leaks – which can disrupt service.

Reliability drives our business. Customers want – and need – energy that is both reliable and resilient in the face of severe weather. They want fewer outages and, when outages occur, they want the lights back on quickly.

For more than a century, Public Service has provided the energy New Jersey homes and businesses need. The 2003 blackout was a wake-up call. Our investments enhance reliability – but do so much more. By modernizing our infrastructure, we create an energy network that is not only more reliable, but also improves safety, protects the environment and, in doing so, creates thousands of jobs for New Jersey’s workforce.

Moving forward, we expect to invest another $6 billion over the next five years to continue improvements to transmission – all part of our ongoing mission to make a reliable network even stronger.

Kim Hanemann

Senior Vice President – Delivery Projects and Construction

One thought on “The tree limb that fixed the electric grid

  1. Will the work in which you are currently engaged harden our portion of the grid against an EMP attack and avoid a complete shutdown?

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