HE Krka – Šibenik: one of the first commercial alternating multi-phase systems in the world

On the Krka waterfalls, on August 28, 1895, the Krka hydroelectric power plant, the first alternating current plant on Croatian soil, was put into operation with a multi-phase electricity production system. At the same time, a transmission line to the city of Šibenik and a distribution system in the city were constructed. Thus, one of the first complete commercial multi-phase power systems in the world was established in Croatia, meaning it had all the characteristics of today’s modern systems. The key figures behind this endeavor were the then mayor of Šibenik, Ante Šupuk, and engineer Vjekoslav Meichsner.

After Edison built the first power plants in London and New York in 1882, the construction of so-called central stations for electricity production began, primarily intended for lighting, using Edison’s carbon filament bulb, first produced in 1879. Due to the limitations of the direct current system, especially the inability to transmit electricity over long distances, many “central stations” had to be built (for example, there were as many as 450 in New York in 1890).

The first direct current power plants in Croatia were built by 1895 in Pula, in the military port, in Rijeka, as well as in the textile factory in Duga Resa, and in the fabric factory in Županja. The first commercial systems intended for public lighting were built in Čakovec in 1893, and in Varaždin and Zadar in 1894. The first alternating current plant with a single-phase generator, for the purpose of lighting warehouses and external lighting in the port, started operating in Rijeka in 1892.

In the early days of creating power systems, there was a struggle between the concepts of direct current and alternating current power systems. This conflict lasted until World War I when the application of direct current power systems practically ceased.

Tesla’s Alternating Current

Nikola Tesla, with the discovery of the rotating magnetic field and the possibility of applying the alternating multi-phase system in 1888, proved that alternating systems have significant advantages over direct current systems, and this new system was applied in various places around the world, including Šibenik. Crucial for the development of the alternating system in Croatia was the construction of the second hydroelectric power plant, Jaruga, on the Krka, in close proximity to the first. It was put into operation in 1903 and is still in operation today. The second plant was much stronger than the previous one and supplied the nearby factory, and later the city. Experiences from the first power plants encouraged foreign investors to build in Croatia. Thus, the currently active HE Miljacka (1906), HE Ozalj (1908), and HE Kraljevac (1912) were built, as well as some other smaller plants that are no longer in operation.

World War I was devastating for our first hydroelectric power plant, Krka (later called Jaruga I).

It was not destroyed in military actions, as there were none in that area, but was dismantled. Copper and iron were removed from the generator to be cast into cannons and shells. It was estimated that one hydroelectric power plant was sufficient, and it was supposed to be restored and renovated after the war. However, this did not happen, so today the remains of the building stand as a monument to the first Croatian electricity enterprise endeavor.