Milestones:Rheinfelden Hydroelectric Power Plant, 1898 - 2010


Date Dedicated
Dedication #
Rheinfelden, Germany
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Achievement date range


Rheinfelden Hydroelectric Power Plant, 1898-2010


The original Rheinfelden plant was an outstanding achievement in Europe's early large-scale generation of hydroelectric power. It was important for its 17,000 horsepower (12,500 kilowatt) output, for pioneering three-phase alternating current later adopted around the world, and using 50-Hertz frequency which afterwards became standard in most countries. Gradually, Rheinfelden entered into joint operation with other stations, from which the interconnected network of continental Europe evolved.

Street address(es) and GPS coordinates of the Milestone Plaque Sites

, Kanalstrasse,D 79618 Rheinfelden (Baden), Germany UTM (WGS84) : Z-32T, E-409787, N-5268660

Details of the physical location of the plaque

The plaques will be mounted on plinths in the grounds next to the exhibition pavilion

How the plaque site is protected/secured

The exhibition pavilion is open to the public during certain daytime hours throughout the week, including Sundays and holidays. The pavilion, and the surrounding grounds where the plaques will be mounted, are under the surveillance of the power company’s security personnel, and are monitored by cameras.

Historical significance of the work

The old hydro-power station Rheinfelden is a pearl from the early stages of real electric power supply in Europe. The power plant stands for the beginnings of large-scale generation of electricity from hydropower, including the transmission to consumer centers. The power company adopted the name “Rheinfelden Power Generation and Transmission Company” and thus expressed the dual role of the enterprise. The plant was commissioned in 1898. Thanks to an innovative design it became possible to derive a legendary 17’000 horse power in electrical form from the River Rhine and to transmit this via high-voltage lines to consumer centers. Three years earlier, the very first large-scale hydropower station in the world had been completed. In North America courageous engineers had succeeded in tapping the power of the giant Niagara Falls. From 1895 hydraulic turbines extracted from the water complex the power of 15’000 hp, to be converted into electric power by generators and transported via transmission lines to nearby cities. The two large-scale power plants are milestones in a development process reflecting the dawn of modern electric power supply. What current type or current system and what frequency should best be applied, was by no means clear. At that time, there was still a system conflict concerning the struggle to decide on the best current system and the best suitable alternation number (later called “frequency”) of the current. The planning engineers and manufacturers of the electrical equipment for Rheinfelden decided, after thorough investigations, for “three-phase alternating current” with 50 periods per second, the “50-Hz rotary current”. It was a decision that was to give the power station a high technical prominence and exemplary role, right up to the present. Thanks to step-by-step improvements and partial retrofits, the electric output − originally 12’500 Kilowatt − was ultimately increased to 25’000 kW. Two of the original three-phase ac generators were providing reliable service until decommissioning in 2011. A few years after commissioning, the Rheinfelden hydropower plant was interconnected for operation with other power stations on both sides of the German-Swiss border and became the nucleus of today’s interconnected network of Europe. This is the second particularity for which the Rheinfelden power plant can claim for being the very first district power station of the world with trans-border operation.

Features that set this work apart from similar achievements

When the Rheinfelden power plant was being prepared, no ideal examples existed to help decide which basic current system and what number of cycles should best be used (it was the time of “war of the currents” and “war of the frequencies”). Comparable predecessors had most diverse characteristics in this respect: For instance, the large-scale power transmission experiment Lauffen-Frankfurt in 1891 operated with the brand-new three-phase alternating current (ac) system but with 40 cycles, by 1895 Niagara Falls went into operation with two-phase ac and 25 cycles, in certain regions of Europe 42 cycles had been established, only some sporadic new plants went into operation with 50 cycles. Most of the new power stations of that time were equipped with single-phase or two-phase ac generators, until about 1897. With the decision for three-phase ac with 50 cycles the Rheinfelden power plant set new standards and launched the triumphant progress “of the right current system”, suitable for both lighting and power purposes.

Significant references

[1a] Emil Rathenau, Die Kraftübertragungswerke zu Rheinfelden. Elektrotechnische Zeitschrift ETZ 17(1896)27, 402−409. (Translated title: The Rheinfelden Power Generation and Transmission Plant). [1b] Allgemeine Elektricitäts-Gesellschaft, Die Kraftübertragungs-Werke zu Rheinfelden. Technische und wirtschaftliche Darstellung der Ausnutzung der Wasserkräfte des Rheins bei Rheinfelden. H- S. Hermann, 1896 Berlin. (Translated title: The Rheinfelden Power Generation and Transmission Plant. Technical and economic description of the Rhine River hydropower exploitation at Rheinfelden). [2] Franz Bendt, Ein Vierteljahrhundert aus der Wirksamkeit der Allgemeinen Elektricitäts-Gesellschaft zu Berlin. Westermann Monatshefte 52(1908)104, 337−353, Georg Westermann in Braunschweig. (Translated title: The General Electricity Company in Berlin: a quarter-century of business activity). [3] Oskar von Miller, Die geschichtliche Entwicklung der elektrischen Kraftübertragung auf weite Entfernung, Elektrotechnische Zeitschrift ETZ 52(1931)40, 1241−1245. (Translated title: The Historical Evolution of Electric Power Transmission over Long Distances). [4] Wolfgang Bocks, Perspektiven mit Strom, Homberger Druck KG, 1994 ,Maulburg. (Translated title: Perspectives with Current). [5] Gerhard Neidhöfer, Technikgeschichtliche Bedeutung des alten Kraftwerks Rheinfelden, Aargauer Heimatschutzpreis 2009, Geschäftsstelle Rheinfelden / Schweiz. (Translated title: Technical and historical significance of the old hydropower station Rheinfelden). [6] Gerhard Neidhöfer, Early three-phase power. Winner in the development of polyphase ac, IEEE Power & Energy Magazine, September/October (2007)5, 88−100. [7] Gerhard Neidhöfer, 50-Hz frequency. How the standard emerged from a European jumble, IEEE Power & Energy Magazine, July/August (2011)4, 66−81.

Supporting materials

The 7 reference files will be sent separately by mail as soon as the full address of the receiver is known. Please sent me the postal address. File:CH IEEE PES Reference - Historical Milestone Rheinfelden.pdf


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Dedication Ceremony

Rheinfelden Milestone Report, a presentation on the dedication ceremony prepared by Gerhard Neidhöfer