At the end of the 19th century, a wider use of electricity began. Although it was a new phenomenon at the time, its advantages attracted a growing number of users.  Together with the spreading of electrical networks, the number of problems connected to its transmission and distribution grew as well.

The problems came from the shortcomings of direct current, which was then in use.  At the electric lines of the length of only a kilometer, drops in voltage were too great, there were great losses during the transport of electric current. 

Furthermore, it was not possible with one electric line to bring different voltages to the users who requested such service.  For example, some factories needed one level of voltage for lighting and a different one for moving engines.  This required separate lines, significantly increasing the cost of transporting this increasingly demanded type of energy.

Due to the newly created problems, two opposing solutions appeared.  On one side there were supporters of the continued usage of direct current, Thomas Edison being one of them.  Their solution anticipated placing production near the users, so that long lines would not have to be used.  The second group of engineers and businessmen, including Nikola Tesla, had a different opinion. 

They deemed necessary the introduction of an entirely new system of production, transport and distribution of electric energy.  The system they supported was based on Tesla’s multi-phase system of alternating current.  These two opposing opinions generated a conflict that came down in history as “War of the Currents.”  The conflict made rivals out of two collaborators – Tesla and Edison.

Thomas Edison

In 1882 Tesla started working in the Paris branch of Edison’s company.  Two years later, in 1884, after his arrival to America, Tesla continued working for Edison in his laboratory in New York.  Although their ideas clashed, Tesla greatly respected Edison, and he wrote thus about their first encounter:

“The meeting with Edison was a significant event in my life.  I was amazed by that extraordinary man who has accomplished so much without an adequate education and scientific experience.  I have studied a dozen of languages, literature and the arts, and I have spent the best years of my life in libraries reading whatever would fall under my hands, from Newton’s Principles to Paul de Cocq’s novels, and I felt like I have wasted the greatest part of my life.  I quickly realized, however, it was the best I could have done.”

Different looks at the future of electrification between these two geniuses caused their parting.  It is a real pity it happened, because who knows what benefit for humanity would have come out of their collaboration.  Already in 1885 the 25-year-old Nikola Tesla founded hi own company, Tesla Arc Light Co.  In his laboratory he worked on perfecting his inventions and creating new ones.  From the departure from Edison until 1888, Tesla patented a large number of inventions in the field of multi-phased currents.

George Westinghouse

He realized that the existing problems in the transportation of electricity could be solved by alternate current, primarily due to the simplicity of shifting voltage levels with a transformer.  Also, the advantages in distribution consisted in the fact that a relatively small current was needed for great voltages, and since the quantity of current mainly influences the loss of electricity during transport, this was extremely convenient.

On May 16th 1888, Tesla presented his discoveries and insights in the American institute of electrical engineers, where he presented a lecture: “The New System of Engines and Transformers of Alternate Current.”  That same year, George Westinghouse, himself an inventor and entrepreneur, bought Tesla’s patents in the area of multi-phase currents, seeing in them the solution for problems that appeared with the use of direct current.  Tesla wrote:

“George Westinghouse was for me the only man in the world who under the given circumstances could take over my system of alternate currents and win the battle against prejudices and the power of money.  He was a wonderful pioneer, one of the true world noblemen America can be proud of, and to whom the world owes endless gratitude.”

Promo poster for the Chicago World's Fair 1893

In the next two years, with the help of Westinghouse’s engineers, Tesla improved his patents in order to adjust them for implementation.

Entering into partnership with Westinghouse and producing an alternate current generator and engine was not the end.  A powerful propaganda, to which the advocates of direct current reverted, was on their side.  In order to prove that there is a danger from alternate currents, Edison and his collaborators were killing various animals with alternate current, and this culminated with the execution of an elephant.

Edison presented a shot of this event at gatherings where he spoke against alternate current.  The fear against the new and the unknown was his ally.  Edison had a custom of saying that direct current is like a river calmly flowing into the ocean, and alternate current a torrent destroying everything in front of it and flooding over the dam.

The progress could not be stopped, however.  On the occasion of the 400th anniversary of Columbus’ discovery of America, in Chicago in 1893, the first all-electric exhibition was organized.  Two companies applied for the task of lighting the event – General Electric Company, which in the meantime took over Edison’s company, and Westinghouse’s company.

The Electric Hall at the Chicago World's Fair

The offer General Electric made was one million dollars.  The largest expanse was related to the copper lines used for transporting direct current.  Their offer was buried by Westinghouse’s, which was two times lower.

On May 1st 1893, the world exhibition was festively opened by the American President Grover Cleveland.  By turning on a hundred thousand bright lamps, he lighted the entire fairgrounds, and the spectacle clearly conveyed to the visitors that the future of electricity lies in alternate current.  “The City of Light” was the work of Tesla and Westinghouse, and it was generated by about nine megawatts of electricity from a generator also housed on the fairgrounds.  In the Large Hall of Electricity, Tesla proudly presented his multi-phase system of generation and transport of alternate current.  The fair was visited by 27 million people who witnessed the victory of Tesla’s inventions in the “War of Currents.”

Chicago's World Fair lit by alternating electric current

After this event, more than 80 percent of requested electrical devices was connected to alternate current.  Direct current was not completely abandoned, however.  The users who were in the direct current network continued using it, but eventually they moved to the AC system as well.  The last 1600 users from Manhattan were disconnected from a DC network in 2005. 

Direct current is today mainly used in cars, as well as in many transfer devices requiring the use of electrical energy housed in batteries.  In electrical networks used in the production and distribution of electrical energy, the use of alternate current is prevalent.  The greatest credit for that certainly belongs to Nikola Tesla.

The Đerdap hydroelectric plant in Serbia

.