New technology can improve electric power system efficiency and reliability

Source: North American SynchroPhasor Initiative, as of March 8, 2012.
Note: Regional PMU data are centralized and archived at aggregators (see stars on map). 

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The term "smart grid" covers a range of devices and systems that leverage recent advances in digital technology and communications to improve the efficiency, performance, and reliability of the existing electric power system infrastructure. Although the "smart grid" is most frequently discussed in terms of advanced electric meters and other distribution system technologies, it also includes important enhancements to the transmission system. In particular, phasor measurement units, or PMUs, are a new "smart" technology being deployed throughout North America (see map), monitoring what happens on the transmission grid.

This map shows a snapshot of PMU deployment as of March 2012. The North American SynchroPhasor Initiative(NASPI) reports there are about 500 networked PMUs installed. NASPI expects that approximately 1,000 PMUs will be in place and networked by the end of 2014, a timeline associated with the Department of Energy's Smart Grid Investment Grant (SGIG) program.

Electric power systems are enormous integrated machines. In the United States and Canada, there are four large electric systems, called interconnections, that underpin the provision of electricity service to all consumers. For example, the Eastern Interconnection covers an area from the Atlantic Coast nearly as far west as the Rockies in the United States as well as much of Canada. For these integrated systems to operate reliably, system operators must continuously match electricity generation to electricity demand, within tight tolerances, as demand changes throughout the day. Further, the operation of each component of the electric power system—every generator, transformer, and transmission circuit—must be closely synchronized.

A mismatch between supply and demand or a breakdown in synchronization can put stress on the grid. If these problems are not rapidly identified and corrected, the result can be deterioration in power quality or power outages. PMU data can be used to monitor and mitigate these problems.

Comparing data between points on an electric system is a good way to reveal stress on the system and home in on the source of the problem. PMUs monitor the characteristics of electricity flowing through a particular location, for instance, at the point where a generator connects to the bulk power system, or at a substation. The ability to compare time-synchronized data on the same timescale, among widely separated locations, is a relatively new achievement, based on two major improvements:

• Speed. PMUs make measurements at short time intervals—typically 30 times per second—significantly faster than the conventional supervisory control and data acquisition (SCADA) technology, which makes measurements only every few seconds. (For comparison, electricity alternates at a frequency of 60 times per second on the system.) The more-frequent measurements from the PMUs can reveal system dynamics that would not be apparent with the older SCADA systems (see chart below).
• Synchronization. All PMUs across an interconnection are kept in precise time synchronization using GPS, leading to the term "synchrophasor data" (in this context, the term "phasor" comes from the mathematical representation of the measurement). This synchronization provides the capability to easily compare system data among geographically dispersed units, creating wide-area visibility across large power systems, which was not previously possible using older technology.

Source: U.S. Energy Information Administration, based on Oklahoma Gas & Electric system disturbance data 

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PMUs can accumulate large amounts of data. Telecommunications technology—via fiber optic, cable, or satellite—plays an important role in compiling synchrophasor data (example: a company forwarding data from 60 PMUs might require two dedicated T1 lines.). Developing the necessary communications networks is currently a factor limiting many real-time applications of synchrophasor data. PMU capability is comparatively inexpensive—often an optional function on standard equipment—but the costs of adding the necessary networking infrastructure are usually larger, as seen in the data collected as part of the SGIG program.

Developing methods for accumulating, analyzing, and distributing vast amounts of data is a challenge throughout the range of smart grid technologies. While there are a number of software applications in use and under development that take phasor data and turn it into actionable information, the industry is still working to understand what high-speed phasor data reveal about the grid's behavior. That insight is needed to make software applications fully usable.

In time, applications for PMUs may include integrating intermittent renewable generators and automating controls for transmission system and demand response equipment, as well as developing increasingly-efficient use of electric power system infrastructure. On a real-time basis, power system operators and reliability coordinators might use synchrophasor data to enhance situational awareness, preventing transmission grid failures, isolating problems, and speeding outage restoration when blackouts do occur. One application may be automated responses to system disruptions, which can execute faster than manual action.

Offline, synchrophasor data are already being used to improve electric system models used in real-time operations and planning, as well as for disturbance analysis and forensic investigation. For example, the investigation into the causes of the 2003 Northeast Blackout required many person-years of labor, but the investigation of the 2011 blackout in the Southwest is proceeding much more quickly, in large part due to the availability of PMU data. Official recommendations made after the 2003 blackout called out the need for time-synchronized data and its use in wide-area situational awareness.

TV transmitter circuit

Description.

The TV transmitter circuit given here uses UK standard 1 FM modulation for sound and PAL for video modulation. The audio signal to be modulated is pre-amplified using the transistor Q1 and associated components. The transistor Q2 has two jobs: production of carrier frequency and modulation. The pre-amplified audio signal is fed to the base of transistor Q2 for modulation. Capacitor C5 and inductor L1 forms the tank circuit which is responsible for producing the carrier frequency. The video signal is fed to the emitter of transistor Q2 via POT R7 for modulation. The modulated composite signal (audio+video) is transmitted by the antenna A1. This TV transmitter circuit can be operated from 12V DC. Either a 12V DC power supply or a battery can be used for the purpose, using a battery will surely reduce noise and improve the performance. If you are going with a DC power supply, then it must be well regulated and free of  noise.

A New Energy Source: Major Advance Made in Generating Electricity from Wastewater

Engineers at Oregon State University have made a breakthrough in the performance of microbial fuel cells that can produce electricity directly from wastewater, opening the door to a future in which waste treatment plants not only will power themselves, but will sell excess electricity.The new technology developed at OSU can now produce 10 to 50 more times the electricity, per volume, than most other approaches using microbial fuel cells, and 100 times more electricity than some.

Researchers say this could eventually change the way that wastewater is treated all over the world, replacing the widely used "activated sludge" process that has been in use for almost a century. The new approach would produce significant amounts of electricity while effectively cleaning the wastewater.

The findings have just been published in Energy and Environmental Science, a professional journal, in work funded by the National Science Foundation.

"If this technology works on a commercial scale the way we believe it will, the treatment of wastewater could be a huge energy producer, not a huge energy cost," said Hong Liu, an associate professor in the OSU Department of Biological and Ecological Engineering. "This could have an impact around the world, save a great deal of money, provide better water treatment and promote energy sustainability."

Experts estimate that about 3 percent of the electrical energy consumed in the United States and other developed countries is used to treat wastewater, and a majority of that electricity is produced by fossil fuels that contribute to global warming.

But the biodegradable characteristics of wastewater, if tapped to their full potential, could theoretically provide many times the energy that is now being used to process them, with no additional greenhouse emissions.

OSU researchers reported several years ago on the promise of this technology, but at that time the systems in use produced far less electrical power. With new concepts -- reduced anode-cathode spacing, evolved microbes and new separator materials -- the technology can now produce more than two kilowatts per cubic meter of liquid reactor volume. This amount of power density far exceeds anything else done with microbial fuel cells.

The system also works better than an alternative approach to creating electricity from wastewater, based on anaerobic digestion that produces methane. It treats the wastewater more effectively, and doesn't have any of the environmental drawbacks of that technology, such as production of unwanted hydrogen sulfide or possible release of methane, a potent greenhouse gas.

The OSU system has now been proven at a substantial scale in the laboratory, Liu said, and the next step would be a pilot study. Funding is now being sought for such a test. A good candidate, she said, might initially be a food processing plant, which is a contained system that produces a steady supply of certain types of wastewater that would provide significant amounts of electricity.

Continued research should also find even more optimal use of necessary microbes, reduced material costs and improved function of the technology at commercial scales, OSU scientists said.

Once advances are made to reduce high initial costs, researchers estimate that the capital construction costs of this new technology should be comparable to that of the activated sludge systems now in widespread use today -- and even less expensive when future sales of excess electricity are factored in.

This technology cleans sewage by a very different approach than the aerobic bacteria used in the past. Bacteria oxidize the organic matter and, in the process, produce electrons that run from the anode to the cathode within the fuel cell, creating an electrical current. Almost any type of organic waste material can be used to produce electricity -- not only wastewater, but also grass straw, animal waste, and byproducts from such operations as the wine, beer or dairy industries.

The approach may also have special value in developing nations, where access to electricity is limited and sewage treatment at remote sites is difficult or impossible as a result.

The ability of microbes to produce electricity has been known for decades, but only recently have technological advances made their production of electricity high enough to be of commercial use.

Nanodynamite New Power Source Found

Researchers at the Massachusetts Institute of Technology (MIT) and RMIT University have made a breakthrough in energy storage and power generation. The power generated relative to the energy source size is three to four times greater than what is currently possible with the best lithium-ion batteries.

The team was working on measuring the acceleration of a chemical reaction along a nanotube when they discovered that the reaction generated power. Now the two researchers are using their combined expertise in chemistry and nanomaterials to explore this phenomenon. Their work titled Nanodynamite: Fuel-coated nanotubes could provide bursts of power to the smallest systems is in the December IEEE Spectrum Magazine, the publication of the IEEE.

Associate Professor Kalantar-zadeh said that his experimental system, based on one of the materials that have come from nanotechnology — carbon nanotubes — generates power, something researchers had not seen before. “By coating a nanotube in nitrocellulose fuel and igniting one end, we set off a combustion wave along it and learned that a nanotube is an excellent conductor of heat from burning fuel. Even better, the combustion wave creates a strong electric current,” he said. “Our discovery that a thermopower wave works best across these tubes because of their dual conductivity turns conventional thermoelectricity on its head. “It’s the first viable nanoscale approach to power generation that exploits the thermoelectric effect by overcoming the feasibility issues associated with minimising dimensions.

“But there are multiple angles to explore when it comes to taming these exotic waves and, ultimately, finding out if they’re the wave of the future.”

Energy conservation

Energy conservation refers to efforts made to reduce energy consumption. Energy conservation can be achieved through increased efficient energy use, in conjunction with decreased energy consumption and/or reduced consumption from conventional energy sources.

Energy conservation can result in increased financial capital, environmental quality, national security, personal security, and human comfort.Individuals and organizations that are direct consumers of energy choose to conserve energy to reduce energy costs and promote economic security. Industrial and commercial users can increase energy usage--- efficiency to maximize

Building design

Elements of passive solar design, shown in a direct gain application

In passive solar building design, windows, walls, and floors are made to collect, store, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design or climatic design because, unlike active solar heating systems, it doesn't involve the use of mechanical and electrical devices.

The key to designing a passive solar building is to best take advantage of the local climate. Elements to be considered include window placement and glazing type,thermal insulation, thermal mass, and shading. Passive solar design techniques can be applied most easily to new buildings, but existing buildings can be adapted or "retrofitted".