Heliostat Cost Reduction – Where to Now?

The Australian National University has been undertaking a review of state-of-the-art in heliostat design, as part of the Australian Solar Thermal Research Initiative (ASTRI). Deep cost reduction is required to ensure solar tower technology becomes competitive, and to achieve the aggressive LCOE targets of ASTRI and other programs like U.S. Sunshot. This paper is a case study for a new heliostat design, and aims to provide directions and identify opportunities for cost reduction. The review examines trends at both a system level and at an individual collector level, to make sense of where the greatest potential for cost reduction lies. At a heliostat system level, we focus in particular on three factors critical to cost reduction: manufacturing and assembly, heliostat size and wind load analysis. A technological review of heliostat componentry highlights those areas we believe have most performance improvement and cost reduction potential, including mirrors, tracking systems, communication systems and structure. The review also identifies cost reducing design features of some recent unconventional heliostat designs, and provides a summary of those features we believe to hold the most promise.