North America's Electricity Infrastructure: Are We Ready for More Perfect Storms?

Are we ready for more perfect storms? W ith the tragic events of 9/11 permanently etched in our minds, the massive 14 August power outage evoked eerie reminders of what shook our world 2 years ago. While preliminary reports indicate that there was no apparent evidence of terrorism, the cascading blackouts were a sudden illumination of our electricity infrastructure's vulnerable condition. This infrastructure affects us all—are we prepared for future storms? The North American power network represents an enormous investment , including more than 15,000 generators in 10,000 power plants, and hundreds of thousands of miles of transmission lines and distribution networks. Analysts estimate it to be worth over US$800 billion. In 2000, they valued the transmission and distribution at US$358 billion. 1 With its millions of relays, controls , and other components, our power network is the most complex machine ever invented. The National Academy of Engineering hailed the North American power-delivery system as the supreme engineering achievement of the 20th century because of its ingenious engineering , catalytic role for other technologies, and impact on improving quality of life down to the household level. 1 Possibly the largest machine in the world, its transmission lines connect all generation and distribution on the continent to form a vertically integrated hierarchical network consisting of the generation layer (as just mentioned), and the following three basic levels: 2 • Transmission. Meshed networks combining extra-high voltage (above 300 kV) and high voltage (100-300 kV), connected to large generation units and very large customers and, via tie-lines, to neighboring transmission networks and to the sub-transmission level. • Sub-transmission. A radial or weakly coupled network including some high voltage (100-300 kV) but typically 5-15 kV, connected to large customers and medium-size generators. • Distribution. Typically a tree network including low voltage (110-115 or 220-240 V) and medium voltage (1-100 kV), connected to small generators, medium-size customers, and local low-voltage networks for small customers. Unfortunately, over the past 100 years, the network has evolved without formal analysis of the system wide implications of this evolution , including its diminished transmission and generation shock-absorber capacity under the forces of deregulation, the digital economy , and interaction with other in-frastructures. Only recently, with the advent of deregulation, unbundling, and competition in the electric power industry , has the possibility of power delivery beyond neighboring areas become a key design and engineering consideration , yet we still expect …