After blackout, improved grid
By Terry Boston
The massive power interruption that brought much of the Northeast and Midwest to a halt a decade ago remains an indelible moment and a persistent call to action.
Aug. 14, 2003, was a typically hot summer day with heavy, but not extreme, electricity demand. Several generators in the Midwest were already down for maintenance when another critically important generator and a few power lines automatically disconnected from the grid for various reasons. The system was vulnerable to a triggering event, and then three large power lines came into contact with trees that afternoon. The resulting interruption cascaded across large parts of the Midwest and Northeast in minutes, leaving 55 million people without electricity and causing $6 billion in financial losses.
While the lights stayed on in Pennsylvania, other states like Ohio, New York, Michigan, Massachusetts and Connecticut, as well as Ontario, weren't so lucky. An Inquirer story headlined "Powerless" captured the disruption: "The exodus of people over bridges. The gridlock at tunnels and intersections. Jammed cell phones. Stranded subways."
The U.S./Canadian investigating team identified a complex web of root causes that can be summarized as "tools, trees, and training." In short, problems with computers at key control centers prevented grid operators from seeing and reacting to developing problems. In Ohio, several transmission lines that had stretched in the summer heat (which is normal) sagged into trees growing unchecked beneath them (which is not). When the lines automatically disconnected to prevent serious damage, power instantly moved to other lines, overloading them and creating a domino effect of lines and generators separating from the grid. Finally, the team noted, there was a lack of rigorous analysis, procedures, training, and communications that would have made operators aware of grid conditions that day.
As we note the 10th anniversary of the great blackout, it's good to see that much has changed since 2003. Prominent among the improvements are new, mandatory national reliability standards, backed up by strong financial penalties for violations. The standards, which include training, certification, and continuing education requirements for grid operators, replaced a system of voluntary rules that worked well for more than three decades, but proved inadequate to modern threats. There are also standards and industry-driven movements for stronger collaboration and information-sharing, as well as for preventing trees from growing near transmission lines.
The grid today is also smarter. Advances in technology have made modern control centers - lined with walls of hi-def data displays - better at presenting real-time conditions to operators. Today, a new wave of devices, called phasors, measures operating conditions 30 times per second from 1,000 locations. They're generating terabytes of data that will one day allow automated responses to problems faster than humans can think. For the grid, they represent a leap in clarity and detail similar to medicine's advance from X-rays to MRIs. More than 5,000 phasors have been installed nationwide, with many more on the way.
Despite these and many other improvements since 2003, the reliability of the nation's electricity supply is still under great pressure. Extreme weather, such as Superstorm Sandy and a windstorm-caused catastrophic damage to power systems in 2012, while record summer heat in recent years has pushed equipment to its limits. Threats of cyber or physical attacks against the grid are ever-present. Hardening the electricity infrastructure against these risks is an enormous and expensive undertaking that will keep planners busy for years.
Other threats to reliability don't result from weather but still carry the risk of interruptions if not managed properly. For instance, the industry is in the midst of the largest and fastest fuel switch in its history. In PJM Interconnection's region alone, which covers Pennsylvania to North Carolina and New Jersey to Michigan, almost a quarter of the coal-fired generation - traditionally our largest source of electricity - will be retired by 2015 due to the high cost of converting old plants to meet stricter environmental controls. Most are being replaced by lower-cost, lower-emitting natural-gas generators and wind energy. Dealing with a sea change of this magnitude in just a few short years was unthinkable for earlier generations of grid managers. Today it is happening largely beneath the radar for most consumers.
The grid today is neither as bullet-proof as we would wish nor as fragile as critics sometimes portray it. A decade after the great blackout, the grid remains a vast complex, interdependent tool - increasingly resilient and with a single, modest task: it makes possible our digital economy and our 21st-century way of life.
Terry Boston, the CEO of PJM Interconnection, served on the North American Electricity Reliability Council, which investigated the 2003 blackout.