The Knüsel Family lives in the canton of Schwyz, where patriarch and father of 4, Sepp Knüsel, has been building tractors for over 20 years under the brand name Rigitrac AG. 

In 2019, with the help of his four daughters, he debuted the continent's first all-electric tractor, and 6 years later, the family won a national award for their invention: the Watt d'Or, o 'Golden Watt.'

"The development of the electric tractor was a long process with setbacks," Theres Beutler-Knüsel, the family's second-oldest daughter and managing director of Rigitrac AG, told Swiss outlet SRF. 

The idea actually came from seeing how many growing operations, farmers, dairies, and feedlots had solar panels on their roofs.

The Knüsels thought it would be brilliant if the companies could use that electricity in more ways. Given that a tractor spends a lot of time sitting around under the sun, a solar panel on the roof might make a substantial difference to total range and running time.

That idea pushed the father-daughters team to develop a prototype while Theres was at the University of Dresden in 2018.

"When we started, many of the necessary individual parts were not yet on the market," Beutler-Knüsel told SRF, adding that the family had to work closely with suppliers to develop all the components for the tractor's eventual mass-production.

Today, the Rigitrac SKE 40 is sold in Austria, Norway, Denmark, Germany, and Switzerland, and even made it into the famous PC video game Farming Simulator. 

It wields four electric motors totaling 84KW, including one for the front wheels, another for the back wheels, and a third for starting. It's too small for the heaviest ag chores, like plowing, but it's widely used for vegetable farming and snow plowing.

Sepp's wife Marlis, and their daughters Edith Winter-Knüsel, Doris Knüsel, and Ruth Durrer-Knüsel all work for the company, with one overseeing advertisement and HR, another leading the sales team, and a third handling supply.

In 2025, the SKE 40 was awarded the Golden Watt award by the Federal Office of Energy. The award is given to innovative Swiss companies and organizations who develop the energy technologies of the future. While the Golden Watt doesn't come with prize money, it does offer substantial amounts of free publicity that Rigitrac AG has benefited from.

Beutler-Knüsel told SRF the Watt d'Or was "great recognition that shows us that we are on the right path."