Durability of solar absorber coatings and their cost-effectiveness

Solar absorber coatings are said to be “cost-effective” when significant efficiency gains are achieved with an acceptable additional cost. Here, an integrated approach to solar power technologies is used for quantifying more rigorously the cost-effectiveness of coatings in the concentrating solar power (CSP) industry. The levelized cost of electricity (LCOE) metric is used in an original way that attributes a cost-effectiveness value to any high-temperature absorber coating via a figure of merit named the LCOE gain efficiency. The LCOE gain efficiency is demonstrated on three different solar absorber coatings: Pyromark 2500, lanthanum strontium manganite oxide (LSM), and cobalt oxide (Co3O4), that coat a hypothetical 100 MWe central tower receiver. To perform the calculation of the LCOE gain efficiency, accelerated aging tests and cost estimates are performed. Depending on the coating properties, an optimal reapplication interval may be found that minimizes the LCOE of the plant, i.e., maximizes the LCOE gain efficiency. In such optimal conditions-and for this typical power tower-Pyromark 2500 paint enables a higher LCOE gain efficiency (0.182) than both LSM (0.139) and Co3O4 (0.083). The solar absorptance is by far the most influential parameter. The cost-effectiveness of Pyromark could be outperformed by a coating that would have a high initial solar absorptance (>0.95), a low initial degradation rate (<2×10−6 cycle−1), and a low cost (<$500 k per application). Application of the LCOE gain efficiency can provide a consistent and objective method to evaluate a variety of receiver designs and other components.