New research yielding secrets behind power transmission

Ever since the Internet caught the public's eye in the early '90s it seems as though everyone is talking about a network of some sort or another. Local area networks, the Internet, intranets, and fiber optic networks are all examples of this "new" concept. While it is true that communications networks are a more recent development, the national power grid is a perfect example of a much older network. It is often taken for granted, but the entire country would cease to function without electric power. We can hardly get by without phones or computers for a day or two; just imagine absolutely no electricity whatsoever.

It took a battery of revolutionary scientists such as Nikola Tesla, Thomas Edison, and George Westinghouse to develop the technology necessary for bulk electricity distribution in the late 1800s. Shortly thereafter, the industrialization of America really created the need for a widespread power grid. The first distribution lines that transferred alternating current over a large distance were constructed in 1891 near Frankfurt, Germany. Those lines quickly reached their limits of 40,000 volts (40kV) as power demands grew. Scientists all over the world rose to the challenge, though, and by 1957 power lines carrying 380 KV were in operation. Today, lines transmitting as much as 1000 KV aren't uncommon.

The current power grid in North America consists of thousands of power plants mostly connected to one another through substations and various circuits. The purpose for this interconnected is twofold. First, it provides a level of redundancy. If one plant is disabled for repairs, or due to a natural disaster, consumers can still be provided with electricity. Also, it allows electricity to be "imported." The cost of electricity varies tremendously with the time of year and temperature, among other factors. It varies so much, in fact, that it's often cheaper to buy the electricity from elsewhere than to produce it locally. Of course, that's not always the case, but the power grid allows for either condition.

The grid itself is made up of millions of miles of electrical wire and cable, transformers and switches. Generally, a power plant produces a low voltage, but high current output. Transformers are special electrical devices that actually raise the voltage from those power plants, but consequently lower the current. Overhead or buried power lines then distribute the electricity to homes, businesses, and other structures. The voltages running through all power lines, while high in comparison to what we see in our homes, is subject to a calculable loss as the distance from the power plant increases. Fortunately, transformers positioned in substations and elsewhere maintain the desired voltage at the cost of current.

Power losses are of a great concern, especially given our society's current state of crisis over energy. To minimize losses, electricity intended to be transmitted over very long distances is kept at an extremely high voltage (200 KV). The higher voltage offsets, and actually curtails losses associated with resistance in the wires, cables, and transformers. The future of power distribution is quite exciting. News of energy crises undoubtedly has much of the world questioning our current practices when it comes to handling electricity.

Efficiency is key, and new superconducting materials may eliminate the need for many transformers as they will be able to transmit electricity with very low associated loss. Current superconductors are expensive, as they require liquid helium or nitrogen to cool them to new absolute zero. A new class of materials, called high-temperature superconductors, promises to be much more cost-effective and applicable.

Even more exciting than that, researchers at Massachusetts Institute of Technology have recently been experimenting with a method of power transmission lost since Tesla's time. Tesla originally invented a way to transmit power wirelessly. The group of MIT researchers have expounded upon his idea to increase the range and efficiency of this technology.

So far, their investigations are in a developing stage, however, the outlook is very hopeful. The technology could one day be used to wirelessly power phones, MP3 players, and other gadgets without ever needing to be plugged in again.