Material constrains of concentrating solar power

Concentrating Solar Power (CSP) has been largely unrestricted by materials availability. According to a study by Chalmers University of Technology in Sweden, enough solar plants could be built to cover at least five times the current global electricity demand.

The recent study provides an evaluation of potential material restrictions for a large-scale application of CSP technology using data from an existing parabolic trough plant and one prospective state-of-the-art tower plant.

Most of the materials needed for CSP are commonplace. However, the study stated that there are some issues that the industry needs to take into consideration. A key concern is the potential scarcity in silver in the coming decades even without a demand from a growing CSP industry. CSP mirror manufacturers may have to examine other reflective surface materials to guarantee cost competitiveness.

The need for nitrate salts (NaNO3 and KNO3) and steel alloys (Nb, Ni and Mo) would also be significant if CSP grows to be a major global electricity supply. Based on a high adoption scenario where CSP reaches 8000 TWh/year in 2050, the study indeed outlined that the solar plants would consume up to 50-120 percent of today's annual nitrate salt production, and 5-15 percent of several common materials such as glass, nickel, magnesium and molybdenum.

Dr Erik Pihl, a professor ath the Chalmers University of Technology, stated that parabolic trough plants tend to use a lot of concrete and iron, while the concept of small heliostat tower plants has a higher use of aluminum and stainless steel. He further stated that the common design of a parabolic trough plant also requires more molten salt per MW than a salt-receiver tower plant, even when the former has fewer storage hours. That means that trough plants appear slightly more sensitive than tower plants to possible salt production bottlenecks, unless other storage techniques can be employed.

Pihl also stated that he expects that material demands for plants will decline as we move for higher steam temperatures and increased plant efficiency. In the short term, the main goal is the replacement of silver in mirrors and as well as an increase in nitrate salt production.

- Anne-Fran?oise Pele
??EE Times US