The lights are going off all over the United States for hundreds of thousands of people at a time, often for days at a time and occasionally for weeks. In 2005 we saw hurricanes in Florida and the Gulf of Mexico snap trees and utility poles. More recently, all across the rest of the United States, we have seen severe storms, whether ice, snow or wind, place countless families and businesses in the dark, while utility crews rush to restore electrical power before the next storm arrives. Storm-driven power outages are not just an inconvenience. They impose non-trivial costs on the economy, they are responsible for a significant percentage of storm-related fatalities, and the vulnerability of a grid strung up in the air is a potential homeland security issue, as well.
Even beyond these powerful storms, “power” poles are becoming bent over with not just electric, but telephone, television and Internet cables. They await the next unsuspecting truck driver, poised to darken neighborhood restaurants and shops before utility crews can replace them with even taller utility poles. What is going on here, and what can be done to reduce the perfect storm of severe weather, increasing bandwidth and aging, mostly above-ground power networks?
Driven as much by aesthetics as the need for more reliable electricity, local communities are asking power companies why electric and other lines cannot be put underground. The answer is neither simple nor cheap. In most west European cities and towns, it is true, local electric distribution lines are commonly placed underground. Storms come and go there as they do here, but almost no one loses power because of them. However, this an artifact of both higher European population densities and the keen foresight of postwar European planners. Can the United States make a transition to a more reliable and visually pleasing power network? What is the calculus of costs and benefits in getting there?
Why the Lights Go Out
Even for power engineers and electricians, electricity is magic. The wires that serve as an “electron pipe” delivering power from generators to our homes are a special breed of technology. Electric power is not only intangible; it is produced and consumed nearly instantaneously, traveling the transmission and distribution system at almost the speed of light. As such, grid operators design and build the power system with contingencies in mind, and operate it so that the balance of electricity supply and demand is maintained, second-by-second, on a regional basis. Large regional interruptions, like the great Northeast USA and Canadian Blackout of August 2003, and one six weeks later in Italy, while newsworthy, are relatively rare and of short duration—measured in a matter of only hours. Not only is the high voltage network or “grid” designed to handle several simultaneous surprises, but, like the circuit breakers in your home, if a large change of frequency and voltage is observed, the system turns itself off before valuable pieces of equipment are damaged.
As electric power gets closer to your house—from transmission lines, to feeders, to the lines down your street—the number of contingencies that the power system is designed to handle drops. Not surprisingly, most power outages occur on this low-voltage distribution system. Many of these outages are small and localized, caused when a pole gets hit by lightning or by a car, or when a transformer simply breaks or is shorted out by various small forces of nature such as squirrels or fast growing trees. In these instances, utility crews can “isolate the break”, thus restoring power to most of the neighborhood and bringing back the final few customers online once the break is fixed. The further you are down the line, the older the power system, or the greater the number of trees and vehicles, the more likely your power quality will be diminished.
Constant vigilance is required to maintain reliability. Equipment ages. Electricity demand increases. Trees grow. Squirrels can be evil. Detroit Edison embarked on an aggressive tree-trimming program after two severe thunderstorms in July 1999 knocked out power to roughly a quarter million customers—each time. It estimates that two-thirds of its power outages come from tree-power line interactions. A week-long series of power outages in Queens last summer has been attributed to, in part, the increasing age and complexity of Consolidated Edison’s local power network, of which large parts are, as it happens, already underground. These are challenges faced by all distribution utilities.
Of course, the occasional switch, squirrel or SUV is relatively easy to handle. But when the system as a whole becomes routinely endangered, either by extreme events or by slower-paced but inexorable climate changes, then we need to revisit how we build and operate the system. Large weather-driven failures of the network have become common over the last several years, affecting millions of consumers per year in cost, convenience and safety. The year 2005 was one of the most active hurricane seasons in recent memory. Hurricane Wilma swept across south Florida on October 24 with winds that remained well over 100 mph, dumping over nine inches of rain as it moved from Marco Island to Palm Beach. While damage was extensive, what was especially notable was how hard Wilma clobbered the sprawling cities of southeast Florida. Newer residential and commercial developments tend to locate their wires underground. Even so, fully six million people lost power in south Florida. Florida Power and Light alone lost almost three and a quarter million customers. Although it was able to restore almost two million of them within five days, with well over 10,000 utility poles damaged, some customers were without power for weeks.
While the power outage from Wilma was larger than many other recent hurricanes, recovery was relatively straightforward. In contrast, floods and storm surges, as with Hurricane Katrina, devastate entire areas, not just roofs, trees and towers. Ice storms probably represent the greatest hazard to above-ground electricity networks and neighborhoods they serve. This is because ice storms tend to be larger both in geographic scope and duration than wind and rain events, and they heavily coat everything along their paths. The massive ice storm of January 1998 that hit upstate New York, northern New England, Ontario and Quebec lasted eighty hours. The build-up of ice from freezing rain and drizzle broke not only branches, but snapped thousands of trees, utility poles and buckled transmission towers. In Canada, roughly four million people lost power and more than a quarter of those remained without power for three weeks.
The Appalachians are routinely hammered by ice storms as well, and the winter of 2006–07 has already seen numerous such events, ranging from the Carolinas to New England. Multiple ice and heavy snow storms have also hit the Plains and Midwestern states, from Texas and New Mexico, through Oklahoma, Nebraska to Missouri and Illinois. Tornado Alley may be becoming Ice Storm Alley, and the footprints of ice storms are much larger than those of tornados. Wind and ice is a particularly damaging combination, snapping not only branches and wires, but entire trees and utility poles. As Gary Rainwater, CEO of Ameren, a Missouri and Illinois electric utility, noted in his discussion of Ameren’s efforts to prevent impacts like those from the November 2006 ice storm, “When a 60-foot tree which is 40-feet from a power line falls on that line, no amount of tree-trimming is going to prevent an outage.”
Recovery from such events often takes weeks. Large numbers of poles and wires need to be replaced. Repair crews commonly come in from other regions to assist with the cleanup and restoration. Unlike summer storms, ice storms and heavy snows can have a devastating effect. Many more people are affected, losing not only lights, refrigeration and the ability to cook, but heat for their homes, too. Missouri as well as neighboring states have already seen multiple ice storms this winter, putting the poor and elderly at risk. In addition to many fatal traffic accidents caused by ice storms, dozens have died of carbon monoxide poisoning from the improper use of portable generators and space heaters designed for outdoor use.
So will putting electric lines underground help? Burying distribution lines can address many of the factors leading to outages large and small. Since underground lines are protected from the most common kinds of outages, resulting from branches, trees and human activity, underground systems suffer fewer power outages. However, it is not possible to put underground lines just anywhere, at least not cost-effectively. Soil conditions and opportunities for corrosion must be considered, as must flood risks and the need to avoid damaging water and sewer mains, gas supplies and other utilities. Together these considerations affect the cost, the ease of maintenance and the long-term performance of underground power lines.
A July 2006 report by the Edison Electric Institute outlines the advantages and disadvantages of underground power distribution. That report and the experiences of several U.S. utilities shows that the reliability of underground systems is superior to above-ground systems, but they also point out that when an underground failure does occur, it takes significantly longer to find and fix it. So for the most common sources of power outages, going underground would help, but not without some substantial tradeoffs.
Determining the cost of underground power distribution systems is a “dark art.” For many cities, underground high-voltage systems in dense urban areas are almost a necessity because tall above-ground lines require rights-of-way that make them hard to squeeze between existing buildings. Therefore, paying to install high voltage lines underneath streets is more feasible, but still very expensive. In addition to the soil and pre-existing utility issues already mentioned, underground cables operate differently from their exposed overhead counterparts, and the interconnections and combined operations of above- and below-ground systems are trickier. Although the numbers are highly variable, based upon whether it is a new system or the conversion of an existing system to an underground one, reports have underground systems costing roughly ten times more than of their overhead counterpart on a per-foot basis, with significant additional costs to hook up homes already connected to the overhead system. Many utilities’ reports about the cost of undergrounding the grid yield truly staggering rate increases, ranging from 50 to 150 percent of today’s rates, and often speak of requiring decades to complete the conversion. However, these studies often calculate the cost of undergrounding their entire systems—each mile of their transmission and distribution systems, not just selected pieces of the network that would significantly improve reliability, safety or visual impact.
In the few instances where American communities have decided to move systems from above to below ground, they—not the power company—have borne the costs, and the primary motivation has been aesthetics, not reliability. NIMBY (Not in My Backyard) remains a large factor in communities’ opposition to new transmission lines. Most Americans, however, are seeing more lines going down their streets with every passing year, mysteriously threading their way through donut-shaped trees. So there is no guarantee that putting electricity wires underground will significantly affect a neighborhood’s appearance. The United Kingdom has put 80 percent of its distribution systems underground, yet middle-class neighborhoods still have above-ground telephone service, with wires radiating out from a central tower like an unadorned maypole. Even so, European cities and towns, at least in the denser portions of town, often have underground electricity service.
Built to Last
The characteristic sprawl of America’s suburbs has given much of the country a “built too fast” versus a “built to last” feel. Might the opportunity of a hurricane or an ice storm allow utilities to put lines underground? In the rush to restore service, this sounds unlikely, unless there are pre-existing plans, materials and manpower to “repair and upgrade” at the same time. For most applications, this might not include undergrounding utilities, but instead putting in more wind- and ice-resilient poles and lines. But as housing and development in America continue their migration toward integrated residential developments, and as the upgrading of pre-existing neighborhood roads and sidewalks continues as well, upgrading and undergrounding utilities should be encouraged. This includes not just putting cables underground, but building future flexibility into the network so that it can accommodate “smart wires” (distribution automation) and the ability to accept distributed power generators such as solar, wind and micro-cogeneration (co-production of heat and electricity).
Whether industry will welcome such “repair and upgrade” or “renovate and upgrade” approaches is a big question. On the hopeful side, most distribution utilities in the United States are still rate-regulated entities. This suggests that, with regulatory pre-approval, including provisions for gradual cost recovery, such an incremental cost approach is at least conceivable for areas serving residential customers. Cities and towns might lead the charge in moving to such a system as part of community smart-growth initiatives. This is easier said than done, however, since detailed plans integrated into construction practices need to be developed well in advance. The moment the National Weather Service issues a warning is not the time to initiate a feasibility study. And regulating what American developers do is a daunting prospect.
What would our cities and towns look like if we did adopt a “built to last” approach? That is yet another question and challenge for civil society, but to once again paraphrase the late Tip O’Neill, “all energy is local.” Maybe it is time to take NIMBY and give it a healthy, proactive “not above my yard” spin. Should the U.S. grid be put underground? The American people will decide. ?