A recently released movie tells the story of how Nikola Tesla’s patent for alternating current (AC) eventually prevailed over Thomas Edison’s direct current (DC) technology. What it does not mention is that DC is not only making a comeback, but also offering new hope to the more than one billion people with no access to electricity.
Thomas Edison dismissed Tesla’s AC system as “impractical”, compared to his simpler, though less efficient, DC system. The problem was that Edison’s solution only allowed for an electrical grid within a one-mile radius from the power source. This made it impractical for transmitting the massive quantities of energy needed by factories and cities.
Tesla’s system was both cheaper and able to transmit power over long distances. In the end the entrepreneur George Westinghouse backed AC because he saw it as the only means to connecting the whole country.
The Current War neatly illustrates how an increasingly desperate Edison launched a campaign of dirty tricks to discredit AC. A scene in the movie, based on a real event, shows Edison electrocuting a horse in a misguided bid to prove that AC is more dangerous than DC. “If Mr. Edison succeeds, he will set us back so far we may never recover,” retorts Tesla elsewhere in another scene.
That is not very fair either. The truth is that most of the devices that we use in our AC-powered homes and offices today — for instance TVs, refrigerators and LED lighting — run on DC power. It is not a sustainable model. Every time we convert DC to AC, the adaptors and transformers we use lose up to 20% electricity as heat energy. Ever wonder why your phone charger gets so hot?
It is why DC is making a comeback in both developed and developing countries via Low Voltage Direct Current. LVDC provides a distributed solution to transmitting electricity, in contrast to the top-down structure of AC that we know today. Traditionally, large utility plants generate electricity and then transport it through a network of high voltage, overhead lines to substations.
When the electricity reaches the substations it is converted to lower voltages for distribution to individual households. With LVDC, production takes place much closer to where the electricity is consumed.
LVDC removes the need to convert from DC to AC and then back again to DC, as the traditional, top-down AC structure requires. This makes DC less wasteful and more cost-effective.
In developed economies, the use of LVDC will help improve energy efficiency and reduce the carbon footprint while ensuring excellent power quality. In developing countries it will allow the direct use of power generated by solar panels, for example, which yield DC current.
The IEC is leading standardization efforts. IEC International Standards for LVDC provide the technical foundation for manufacturers to build safe DC products and guide installers of LVDC systems anywhere in the world. They allow regulators to bench-mark and compare systems from different vendors.
International standards will facilitate the broad roll-out and application of LVDC technologies and underpin local manufacturing of appliances. They will help accelerate commercialization and open up markets to fair competition which benefits the end consumer.