Are we having another War of Currents? Nikola Tesla and Thomas Edison were two of electrical history’s most influential energy-related engineer/inventors. Their battle in the 1880s brought about controversy of AC vs. DC power transmission (See my article on EDN). Of course we all know how that turned out when we turn on a light in our home or even charge our Smart Phone or Tablet (Oh those ugly, inefficient wall warts!)
So much of what we have in industry and in our homes is powered by DC (Just look at what powers the ICs in 99.9 % of our devices, appliances, etc.) Plus we can eliminate inverters in UPS and PFC correction in AC power supplies which means better efficiency. Copper is expensive and transmitting at higher voltage means lower current so less copper is needed in transmission lines.
Compared to regular -48V DC, 400V DC reduces copper wire by up to 80 percent, reducing costs in installation and operations. (Image courtesy of Emerson Network Power)
It certainly appears the War of the Currents may not be over yet. But instead of continuing in a heated AC vs. DC battle, it looks like the two currents may end up working in parallel to each other in a sort of hybrid solution. (Tesla and Edison may now rest in peace)
The Emerge Alliance, a member of the U.S. Green Building Council, is at the forefront of the effort to develop standards that will lead to the adoption of DC power distribution in commercial buildings.
I really like their vision of DC microgrids dispersed throughout commercial buildings (Starting with commercial buildings where DC can make the most difference in efficiency and I hope this effort will move to our homes as well) as a means to better efficiency by eliminating the energy loss in the AC to DC power conversion elements to power DC devices.
The project, which began in 2012 and is funded with 18 M Euros, will end in 2015. They believe that the drawbacks of solely using the AC grid can be improved by changing to a mixture of AC and DC sources for electricity distribution in buildings.
Counting on recent advances in semiconductor technology, nanoelectronics and software will help manage the combined AC and DC distribution inside buildings. This effort and others like it will foster research activities in current sensors and 1.2 kV micro-pattern trench IGBT technology to make 380 V DC reliable, cost attractive and energy efficient.
In 2013 the CPUC began an energy storage goal of 1.325 MW for the Pacific Gas & Electric Company (PG&E) by the year 2020. Storing energy means having today’s AC power converted to DC through rectification and storing in some sort of battery or other storage device. Then, when that stored energy is needed, re-convert that DC to AC through a power inverter. A better way is the Bi-directional power inverter5. Quite a waste of energy—DC Power distribution would help immensely here. A bi-directional inverter is typically used for this process.
source: http://www.edn.com/design/power-management/4432745/DC-Power-Transmission–War-of-Currents-compromise
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