A glimpse at keeping mirrors clean in the desert
ASTRI researcher, Ben Duck, recently toured Solar Reserves Crescent Dunes CSP facility as part of work conducted to improve the Operations and Maintenance (O&M) costs for solar thermal installations. The facility is a large single tower receiver CSP plant system with over 10,000 heliostats powering the 110 MW plant. The site is the first utility scale plant in the world to be equipped with a molten salt power tower where molten salt is pumped up the tower to the receiver heated to 566 °C by the focussed sunlight. The hot salt is then stored and used to generate power as required using steam turbines. The storage capacity allows for generation up to 10 hours without further solar input removing the need for backup fossil fuel generators for periods without solar resource.
Ben was fascinated to observe the magnitude of the heliostat field. Standing within the field gives the impression of being in an artificial forest in the otherwise sparsely vegetated high desert of western Nevada. Despite the plants large size (2.8 km in diameter) each of the heliostats is scheduled to be cleaned in two week intervals. This cleaning frequency is necessary due to the plants location next to the sites namesake sand dunes. The plant is entering the final stages of its commissioning and gearing up for the first extended power production runs. It was interesting to see a plant at this advanced stage of development and the O&M issues they face, with ASTRI working to research novel ways to reduce the costs in this area.