Heliostat Cost Reduction for Power Tower Plants

Heliostats typically contribute to about 40 % of the total installed costs in a concentrated solar power (CSP) tower plant. The objective of this study is to investigate the effects of heliostat size on the levelized cost of electricity (LCOE). These effects are analysed in a power tower with a net capacity of 100 MWe with 8 hours of thermal energy storage in Upington, South Africa. A large, medium and a small sized heliostat with a total area of 115.56 m2, 43.33 m2 and 16.69 m2 respectively are considered for comparison. The heliostat cost per unit is calculated separately for the three different heliostat sizes and the effects due to size scaling, learning curve benefits and the price index is considered. The annual operation and maintenance (O&M) costs are estimated separately for the three heliostat fields, where the number of personnel required in the field is determined by the number of heliostats in the field. The LCOE values are used as a figure of merit to compare the different heliostat sizes. The lowest theoretical LCOE value of 0.1960 $/kWhe is achieved using the medium size heliostat with an area of 43.33 m2 for this power tower configuration.