Year: 2026
Type: conference-paper
Abstract: Solar tower plants require cost reduction in the solar field, which represents 30-50% of plant capital costs. This study investigates cable-driven heliostats as a lower-cost alternative to conventional gear-driven systems. A 1 m2 prototype using cables, stepper motors, and worm gearboxes was built and tested. Outdoor tracking tests measured mean errors of 15-16 milliradians, exceeding the one milliradian target required for CSP applications. The main problem occurred at a pitch angle of about 75 degrees, where the unequal cable tensions caused loss of control. When operated manually, without automated control, pointing accuracy improved to 1.6-4.7 milliradians, showing the control algorithm was the limiting factor. The prototype drive mechanism cost $431/m2, representing 70% of the total system cost. Cost projection for a 48.5m2 heliostat estimated that the drive mechanism could be reduced to $7.32/m2, compared to the $16.08/m2 for the Stellio heliostat. However, these estimates assume the technical problems can be solved.
Authors: Rorisang Lekholoane, Craig McGregor
Institution: Stellenbosch University
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: diamond
Funder: Universiteit Stellenbosch
OpenAlex ID: W7223291007