As with so many terms bandied about in mass media, "Smart Grid" is a cutesy umbrella term that allows politicians, analysts, and newscasters to vaguely refer to a collection of technologies that neither they nor their audiences fully comprehend, with advantages that are easily stated, and of uncertain measurability.
While that sounds pretty negative, let me point out that nothing in the above paragraph says anything against the technologies themselves, or their value, but merely pans vague marketspeak terms in general, and the folks who rely on them for ... anything.
Smart grids are part of a general technology trend toward incorporating embedded microcontrollers and data-communication capabilities into all sorts of previously existing devices. For those unfamiliar with them, a "microcontroller" is an integrated circuit that includes a microprocessor and peripheral circuits that allow the microprocessor to sense conditions and events in the external world (data acquisition) and put out signals to drive actuators in the external world (control).
Perhaps the first "smart" devices were automobile engines, which came under microprocessor control during the late 1970s, long before the term "smart xxx" became current. Such engine control modules (ECMs) sensed such variables as outside air temperature and throttle position, and used that information to control such parameters as fuel/air ratio and spark timing. Later, ECMs gained the ability to communicate with additional embedded microcontrollers managing such functions as anti-lock braking systems (ABS) and alarm systems. Modern automobiles now contain dozens of networked microcontrollers operating nearly all functions.
Today, most significant appliances operate under guidance of microcontrollers. Microwave ovens, dishwashers, clothes dryers, televisions, and home thermostats are familiar examples. The extent to which manufacturing operations rely on "smart" technology is even more profound.
Electricity generation and distribution networks, however, are far behind other industries in incorporating smart technology. That is the impetus behind all of the noise and fury about "Smart Grids" in the media.
To be fair, there are significant barriers to incorporating smart technology into electric-power infrastructure. Most significantly, it is imperative to keep the system operating reliably while applying new technology to it. Second, the cost of upgrading existing equipment that was never intended to be part of a computer-integrated system is, shall we say, large. There are many additional issues to be considered when making the move to smart utility grids.
The motivation to incorporate computer control and networking technology into the electric power system is not just to make it more "modern." The concept avoids Scheiber's Rule (Just because you can doesn't mean you should.) by solving a number of present and future problems arising from electric-utility development trends.
The first issue is the fact that the present distribution grid developed from early systems where a single generating plant distributed power to an isolated netword of loads. That placed the responsibility for maintaining voltage, frequency, and phase of the provided electricity squarely on one generating facility. Such installations are amenable to simple closed-loop control.
Later, but still quite some time ago, outputs from multiple generating plants were combined to supply power to the user network. That created the issue of coordinating the output levels and phases of the sources. At least, the sources on a given network were controlled by a common authority capable of centrally guiding the generators via more complex closed-loop control.
Problems became serious when power-distribution networks were interconnected to allow power sharing between sources operated by separate authorities. This makes simple reactive closed-loop control problematic. When you have multiple agents independently providing control inputs in response to observed conditions, the system becomes chaotic. This is not a slam on the engineers who designed and operated the system. It's a fact of life dictated by mathematics. Voltage variations, unpredictable frequency and phase shifts, and seemingly random catastrophic failures ensue.
Happily, all the folks on the supply side of the system were highly intelligent professionals who realized that the only solution was to co-operate their power-generation controls. We'll call it meta-control, where individual operators don't blindly react to every movement of the controlled system, which is what drives the system into chaotic behavior. Instead, when they observe a departure from nominal status, they first communicate among themselves, and devise a coordinated response that brings the entire system back toward nominal.
You can do that when there are relatively few operators. As the number of operators grows, the time needed to communicate and devise a coordinated strategy becomes longer, while the frequency and severity of divergences become more severe.
In the past, the economics of power-generation have favored large generating stations because they can be made more efficient. Costs for fossil fuels and nuclear power scale more slowly than generating plants' output. Emerging energy sources, such as photoelectric and wind power, have been billed as "free energy sources," although they are nothing of the kind, so power-plant efficiency figures less in the installation decision. Thus, we expect to see many more smaller plants. With more small plants, the number of sources that need to be coordinated will rise dramatically, and system-control cost and difficulty will increase.
The assumption is that increased deployment of smart-grid technology will make it possible to maintain system control in the face of increased chaos. High-speed data sharing is to improve coordination while expanded computer automation improves the speed and quality of meta-control decision making.
According to Wikipedia, support for smart grids became federal policy with passage of the Energy Independence and Security Act of 2007. The law, Title13, set out $100 million per fiscal year in funding for fiscal years 2008-2012, established a matching program for states, utilities and consumers to build smart grid capabilities, and created a Grid Modernization Commission to assess the benefits of demand response, and recommend protocol standards.
The Act directs the National Institute of Standards and Technology (NIST) to coordinate the development of smart grid standards, which the Federal Energy Regulatory Commission (FERC) would then promulgate through official rulemakings. Smart grids received further support with the passage of the American Recovery and Reinvestment Act of 2009, which set aside $11 billion for the creation of a smart grid.
Progress has been swift, as it needs to be. Federal Energy Regulatory Commission (FERC) issued a proposed policy statement and action plan on 19 March 2009 for standards governing the development of a smart grid. However, FERC noted that the electric industry started moving ahead with smart grid technologies prior to these government initiatives. The Commission is proposing to establish some general principles that the smart grid standards should follow.
We have known for some years that the trend was toward more numerous smaller power plants. The handwriting has been on the wall since the introduction of a feed-in tariff (FIT) system in 1978. A feed-in tariff is an incentive structure to encourage the adoption of renewable energy through government legislation. The regional or national electricity utilities are obligated to buy renewable electricity (electricity generated from renewable sources, such as solar photovoltaics, wind power, biomass, hydropower and geothermal power) at above-market rates set by the government. The higher price helps overcome the cost disadvantages of renewable energy sources. The rate may differ among various forms of power generation.
FIT means that any Tom, Dick, and Harriett with access to enough cash can set up a generating station, then sell the power to utilities, which are obliged to buy it. This model works well for facilities, such as hospitals and certain manufacturing operations, that need to maintain back-up power generation plants in the event of power failure. Most of the time these generators stand idle. FIT allows their owners to defray some of their cost by running them during peak periods, when demand may exceed fixed-power plant capacity and electricity costs (and FIT repayments) are largest.
The unintended consequence, of course, was a more chaotic electricity environment. Specifically, since a hallmark of chaotic systems is scale invariance, departures from nominal expanded to higher spectral frequencies with smaller amplitude signals (amplitude varies inversely with frequency. While these departures are smaller, their higher frequency translates into the need for faster response. Utilities began experimenting with smart-grid technology in hope of reigning in chaos over a much larger bandwidth.
ADDITIONAL RESOURCES:
U.S. Department of Energy Smart Grid
American Superconductor Smart Grid:
It's More than you Think
