 | By Abby RussoCommunications Intern |
The following blog was written by one of our Summer 2017 interns. For more information about our internships, visit our internship page here.
In the late 1880s, two inventors waged a bitter feud over whether alternating or direct current technology would supply consumers with their electricity. Those inventors were Thomas Edison and Nikola Tesla, and their feud lives on. For years, Tesla and Edison tried to discredit one another, to the point that Edison electrocuted an elephant with AC power to show that it was dangerous, an action which, in my opinion, was uncalled for. In the end, along with the help of his benefactor George Westinghouse, Tesla’s AC system appeared to have won the so-called war of currents, and we’ve been using predominantly AC power ever since. However, new technology and renewable energy have given Edison’s DC system new life.
Direct current and alternating current describe two systems of creating power in a circuit. In a direct current system, power runs continually in a single direction while in an alternating current system, power reverses direction a certain number of times per second, about sixty times in the United States.
When Tesla and Edison’s different transmission systems were initially debated, AC power was better for transmitting large amounts of electricity over long distances and could easily be converted to different voltages using a transformer. While Edison claimed DC was safer because it traveled from the power station to the consumer at a low voltage, it could only travel a radius of 1 1/2 miles from its power station which wasn’t wildly effective. Westinghouse funded the first AC power plant at Niagara Falls to power New York City and AC power was adopted afterward, ending the war of currents for the time being.
We still receive electricity through AC systems for the most part in the United States, but it isn’t perfect. AC falls short in part because it loses more energy than DC when traveling, so energy is wasted in transit. Also, while we get AC power supplied to our homes, most small devices and household appliances are powered by DC. They convert energy from AC power provided in outlets to DC power within the device itself, which is not only inefficient but results in a further loss of energy. Multiple conversions between AC and DC result in at best between 5-10 percent of energy received to be lost. Even more energy can be lost after many conversions and through poor equipment for those conversions.
AC systems also fall short due their mismatch with power generated by renewable sources. Many sources of clean energy, like solar cells and wind energy produce DC power, so using that power requires two conversions--DC from renewable sources to AC to power outlets back to DC to power devices--which, as you may have guessed, is inefficient. More renewable energy is being incorporated into electrical grids and people want to eliminate conversion waste to maximize the use of the DC power they generate, which is giving Edison’s system new life.
To maximize efficiency, several alternatives to the current system have been proposed to use AC and DC systems together. One proposal would create a system of direct distribution of DC power from renewable sources to devices taking DC power to eliminate energy losses in the conversion process. Other systems include converting AC power to DC power at the front door of buildings to minimize the number of conversions in order to use smaller devices.
Since Edison’s days, DC has become significantly more stable, and new forms of DC have been developed to incorporate more renewable energy into the grid and to transmit energy over longer distances with less energy loss. High voltage DC power makes it possible to use DC on larger power grids than in the past and allows the full potential of renewable energy sources to be used, especially when that power is coming from a remote area. For example, energy is brought to Southern California using HVDC from hydropower in northern California and from wind generated power in Wyoming. Many countries, notably China, have been investing in HVDC to integrate new forms of energy and to waste less.
Although I prefer Tesla ito Edison, DC power especially in its high voltage form has new advantages in incorporating green energy to the grid and wasting less. Apparently, the feud between Tesla and Edison hasn’t quite reached its conclusion—I wonder if they would be horribly offended to learn that their systems have been working together for years.