Dive summary:

• Finnish elevator maker KONE says it now has a carbon-fiber belt that can replace steel ropes as the lift method, reducing weight enough to make a kilometer-high elevator run possible while saving energy and reducing maintenance costs.
• The belt costs more than steel cable, however, and KONE is not saying what the extra investment would be.
• The belts are 2.5 centimeters wide (slightly less than an inch) and a half-centimeter thick and comprise four carbon-fiber cores with an epoxy resin shell, and KONE says they resonate at a different frequency than steel rope, so elevators would not have to slow during windy weather that sways buildings.

From the article:

Weight reduction has been the key aim of the nine-year development of the patented KONE UltraRope system, says Johannes de Jong, the company's head of technology for major projects. ...