The widespread use of alternating current (AC) transmission lines can be credited to two individuals: Nikola Tesla and George Westinghouse. Tesla invented and developed the AC power distribution system, and Westinghouse promoted its benefits over direct current (DC) during the “War of the Currents” in the late nineteenth century. On the other side of the battle was Thomas Edison, inventor of the DC system.
Ultimately, AC won over DC, and by the early twentieth century, nearly all transmission and distribution lines worldwide were AC. This was largely because AC could be easily transformed to higher voltages, and therefore could transport power over longer distances than DC.
However, later technological innovations allowed for the conversion between AC and DC and for the generation of high voltage DC (HVDC) power. Now, AC and DC transmission lines coexist in the United States and all over the world. While the electric grid in the U.S. is still overwhelmingly made up of AC lines, HVDC systems are advantageous for certain applications. In fact, HVDC is now the preferred technology for transporting renewable energy over hundreds of miles, as is the case with Clean Line’s other transmission line projects.