The United States is served by an extraordinarily complex and effective electric system. The three major parts of the system—generation, transmission, and distribution—work together to bring reliable and affordable electricity to virtually everyone in America, thus providing a service that is essential to the nation’s security and well-being.
More than 40 percent of all energy consumed in this country is used to generate electricity. Electric power is generated from a variety of energy sources wherever it is convenient and economical and then transmitted to users wherever they may be. The high-voltage transmission system links generating stations with the lower-voltage distribution systems that deliver power to users.
The focus of the articles in this issue is on the transmission and distribution (T&D) system, which has been called the world’s largest “machine” and is part of the greatest engineering achievement of the 20th century (NAE, 2003).
Although the system as a whole has worked very well up to now, it could be even more economical and reliable. Furthermore, strains on the system are increasing for several reasons, and evolving requirements will create even more pressure. As demand for transmission services increases, competition and the search for cheaper power have led to independent power generation far from load centers. At the same time, investment in transmission has lagged, in part because structural changes in the industry have failed to reward new investments. For the same reason, aging equipment is not being replaced as rapidly as it should be. In some cases, public opposition delays or stops the construction of new lines, which may stretch for hundreds of miles and cross many jurisdictions (NAS, NAE, and NRC, 2009).
These issues can and are being addressed. Of greater concern for the future are problems associated with (1) the integration of intermittent renewable resources, such as wind and solar power, and (2) disruptions caused by terrorism or natural disasters.
Serious problems will have to be overcome for wind and solar electric power to become a large part of the generating capacity of a region, because both provide only intermittent power, that is, they operate only when conditions are favorable. Thus the power level can ramp down rapidly when the wind dies down or the sun disappears.
But electricity has to be supplied continuously. Therefore, not only must fast-reacting backup capacity be available, but the grid has to be able to adapt rapidly to changing conditions. Vijay Vittal discusses the impact of intermittent renewables on the grid and how the grid can be modified to handle them.
Terrorism or massive natural disasters could inflict considerable damage on critical components of the grid. The physical damage they could do has long been understood. However, cyber attacks have received considerable attention only recently. The increasing sophistication and ability of hackers and saboteurs to disrupt service is the subject of an article by S. Massoud Amin.
Modernizing the grid will go a long way toward addressing these concerns, as well as toward relieving congestion. Clark Gellings reviews the main candidates for further development. He also explains how increasing dependence on electricity could actually reduce emissions of carbon dioxide.
Modernizing the grid will require installing modern equipment. John Caskey asks where that equipment will be manufactured. If it is imported, as much electrical equipment is these days, our vulnerability to foreign disruptions could be increased. Large power transformers, which are all imported now, are a particular concern, and the world’s production capacity is quite limited.
Another potential constraint on modernizing the grid, or even just operating it efficiently, is the looming scarcity of electrical engineers who are educated and have the experience to operate this massively complex system. Many highly skilled engineers are nearing retirement, and engineering schools are graduating far too few new engineers to fill the replacement pipeline. Don Russell of Texas A&M describes this problem, which may be approaching crisis levels. Fortunately, he sees some potentially favorable developments and suggests some steps we could take to alleviate the problem.
Finally, Richard Schuler provides an overview on how the evolution of the T&D system into the smart grid can encourage innovation and new patterns of consumption in our modern society. He sees the smart grid as a bridge that can link people to technology and sustainability. The information flow supported by the smart grid can help consumers make intelligent decisions and, perhaps, avoid the resource depletion that led to the collapse of many past civilizations and facilitate the exploitation of renewable resources to reduce pollution.
Today, most people take reliable electricity for granted, except when it isn’t available or when the monthly bill goes up. But continued reliability is not a given. Today’s T&D system, as massive and complex as it is, must and will change. Electricity is too important to modern society to risk letting it become unreliable.
The articles in this issue do not cover all of the issues associated with the grid, but they touch on the important ones. We hope they give readers a sense of the magnitude of the problems we face and the necessity of solving them.
NAE (National Academy of Engineering). 2003. Greatest Engineering Achievements of the 20th Century. Available online at http://www.greatachievements.org/.
NAS, NAE, and NRC (National Academy of Sciences, National Academy of Engineering, and National Research Council). 2009. America’s Energy Future: Technology and Transformation. National Academies Press.