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Updated: Nov 13, 2021

By David John Smith

Last week, we learned about the fateful meeting between Sam Eyde and Kristian Birkeland. The adventure that is the Rjukan-Notodden Industrial Heritage story all began one cold winter’s night in Oslo on February 13, 1903.

As they ate dinner that evening in February 1903, Birkeland asked Eyde what question was occupying his mind.

To this Eyde replied,

“What I want most of all is the most powerful electrical discharge on earth”.

Birkeland exclaimed:

“That I can get for you!”

That very evening, Birkeland and Eyde even talked of a new method of binding the nitrogen in the air. They agreed to meet the next day, there was no reason to wait. It was just four days later they signed an agreement, and a few days later an agreement to jointly apply for a patent for a "method of manufacture or procedure" which Birkeland had invented.

Work Begins

On February 20, 1903, Birkeland filed the first patent application for the use of the electric arc to extract nitrogen from the air. Both this patent and several following ones were all listed in Birkeland’s name and several later patents were granted in Birkeland's name. Eyde was, perhaps, in this phase most concerned with ensuring rights and getting the work started.

Work did begin in earnest. Using a miniature furnace at the university, Birkeland tested the electric arc, documents showing he was successful in producing nitric acid. He quickly upscaled in size moving to larger facilities that provided greater electric output and more room.

Arendal and Notodden

By August, the experiment managed to produce nitric acid in a gas balloon. In October, the project was once again moved to larger facilities, and it was here that the first proper Birkeland/Eyde furnace was taken into use; an iron furnace with a diameter of one metre and an output of up to 50 kW. One year later, in October 1904, the test activities moved to Vassmoen in Froland near Arendal as results continued to improve.

Notodden was the next step when Sam Eyde cut a deal with Tinfos AS to lease 2,000 horsepower in electricity to continue to test Birkeland’s method of extracting nitrogen from the air.

Tinfos had agreed to deliver up to 2,400 horsepower for a period of 3 years - but just a few months later an additional 3,000 horsepower was requested.

Norsk Hydro Begins

Then came a famous milestone when in 1905, the company Norsk Hydro was founded, with the goal of producing synthetic nitrogen fertilizer using the Birkeland / Eyde process.

Even then, Eyde was well-aware that this process was energy demanding and their factories must be located close to major power sources.

The stage was set with the choice of Notodden with the relatively powerful Tinn River (Tinnelva). There was still work to be done with the testing in Notodden of the electric arc method. The goal had always been Rjukan to the north, but Notodden would provide the important test ground for the process and the methodology.

Birkeland and Eyde were on their way to make industrial and scientific history.

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