Power engineering continues to grow and offer potential for innovation (see “Watch These Three Power Conversion Trends”). Yet the Smart Grid provides the widest range of opportunities for electronic designers across a range of hardware and software sub-disciplines (Fig. 1). To understand where the opportunities lie, though, it helps to get past some misconceptions about the Smart Grid.
It isn’t about replacing old electric meters with new ones that say you’re using more electricity when you haven’t changed anything else in your house (see “PG&E’s SmartMeter Rollout Off to Rough Start” in the San Jose Mercury News, www.mercurynews.com/ci_13774449?) or about the power company remotely turning off your refrigerator, as I’ve heard some people complain. It’s about engineering a realistic, albeit complex, alternative to simply building new physical plants, a superficially direct approach that never attracted the necessary investment or public support.
WHY A SMART GRID?
On November 9, 1965, at about quarter past 5 in the afternoon, I was shooting hoops with a bunch of my fellow grad students, using a rusty basket on a utility pole in Troy, N.Y. A wild blocked shot brushed a power wire and all the lights went out. Every one of us, all EEs, forgot everything we knew about electricity and thought, “Uh-oh. What have we done?”
Of course, it wasn’t us. A safety relay at a generating station in Queenston, Ontario, had been set too low. A chain of quirky events propagated through the grid and some 25 million people across 80,000 square miles of the U.S. and Canada lost their electricity for as long as 12 hours.
Ever since the 1965 East Coast blackout (and with every subsequent blackout), we have been hearing that the North American electrical grid is antiquated and brittle and that it needs to be upgraded. Why don’t we just do that? A 2003 report by the U.S. Department of Energy, “GRID 2030 A National Vision for Electricity’s Second 100 Years,” provides some background (Fig. 2).
“It is becoming increasingly difficult to site new conventional overhead transmission lines, particularly in urban and suburban areas experiencing the greatest load growth. Resolving this siting dilemma, by a) deploying power electronic solutions that allow more power flow through existing transmission assets and b) developing low impact grid solutions that are respectful of land use concerns, is crucial to meeting the nation’s electricity needs,” the report says.
“The ‘technology readiness’ of critical electric systems needs to be accelerated, particularly for high-temperature superconducting cables and transformers, lower-cost electricity storage devices, standardized architectures and techniques for distributed intelligence and ‘smart’ power systems, and cleaner power generation systems, including nuclear, clean coal, renewable, and distributed energy devices such as combined heat and power,” it continues.
According to the report, there are more than 3100 electric utilities and nearly 2100 non-utility power producers, including both independent power companies and customer-owned distributed energy facilities. Not counting homeowners with grid-tied solar systems on their roofs, that adds up to 4200 separate entities selling and distributing electricity over what’s called the bulk power system.
The bulk power system consists of three independent networks: Eastern Interconnection, Western Interconnection, and the Texas Interconnection. These networks incorporate international connections with Canada and Mexico.
All told, U.S. commercial and public-utility power plants number around 10,000. Although there are “distributed energy” plants that use “waste” heat, in general, the average thermal efficiency of electrical generating plants is around 33%. Most of the existing capacity is 30 or more years old.
Who owns the power plants? Interestingly, there has been a recent shift in ownership, from regulated utilities to competitive suppliers. The share of installed capacity provided by competitive suppliers has increased from about 10% in 1997 to about 35% today. Recent data suggests this trend is slowing, but there is a clear trend toward for-profit electrical generation using equipment that used to be owned by public utilities.