Protecting steel structures in CSP plants: A different approach

Steel is widely used in CSP plants and it represents an important part of the total solar field cost. Considering the latter accounts for between 40 % and 50 % of the CAPEX of a plant, a product that increases its lifetime will result in substantial cost savings for CSP developers.

Magnelis has been employed in several PV plants. Picture credit: ©MetalSistem 2013.

That is precisely what Magnelis, a new coating system for steel, aims to do. According to Dörte Reinke, Business Development Manager Solar at ArcelorMittal, “this metallic coating system offers protection in the harshest environments."

The Luxembourg-based company is so certain about Magnelis’ properties that it offers a 25-year warranty. CSP Today spoke to Reinke to find out more about the product’s characteristics.

CSP Today: What exactly is Magnelis?

Dörte Reinke: ArcelorMittal is involved in the production of steel and a few years ago it launched a special coating product called Magnelis, which is a combination of zinc, aluminium and magnesium. This special chemical composition offers a higher corrosive resistance in comparison to zinc-only based coatings.

Magnelis is also able to “self-heal” on cut edges, where corrosion typically begins. This “self-healing” property ensures Magnelis performs at least three times better than normal galvanizing products.

CSP Today: How does using Magnelis impact CSP plants?

DR: First of all, I think it is important to provide an explanation of the different galvanising processes. There are two main procedures. In the first case, a process called batch hot-dip galvanizing is used, where all the pieces that form the supporting structure of the mirrors in the solar field are assembled on site. The steel structures need to be dipped into a zinc bath in order to be protected from corrosion.

Doing this, however, may result in an uneven coating as some layers will be put on top of each other in the process of plating. In the same instance, it may be very time consuming and sometimes, impossible to do locally. For instance, in Morocco I learnt from some EPCs that there were no galvanizer companies around to complete the coating process.

In the second process, which is called pre-galvanization, the steel goes directly through a continuous bath process to receive its final metallic coating. Therefore, operators do not end up having separate pieces to dip one by one, which results in a homogeneous coating.

By adopting the second method, companies not only get a more even coating of their steel structures, but they also skip the whole galvanization process and avoid all the logistics and costs involved. Considering the remote locations where most CSP plants are built, this translates into important savings for developers.

CSP Today: Most coating products contain zinc. How is Magnelis any different from them?

DR: Magnelis consists of 3,5 % aluminium, 3 % magnesium and the rest is zinc. The 3 % magnesium is crucial as it creates a stable and durable layer across the entire surface, which gives a far more effective corrosion protection than other pure zinc-based coatings.

CSP Today: What about the environmental effects of these chemicals?

DR: Magnelis ensures the preservation of natural resources since it uses less zinc than pure zinc coatings and considerably diminishes the zinc runoff in soils.

CSP Today: What is the track record of Magnelis in the solar industry?

DR: Magnelis has been in the market for around six years and it has consistently been used in PV plants, especially in Northern Europe, France and Germany. Recently, our product has been used as a coating system in a 37,5 MW PV plant in Dorset, in the United Kingdom. We are now looking forward to exciting developments in the CSP industry in 2015.

A sample of Magnelis. Photographer: Jeroen Op de Beeck. Image courtesy of ArcelorMittal.  

CSP Today: What impact could Magnelis have on the lifespan of the steel structures in CSP plants?

DR: It very much depends on the market. If you have very severe climatic conditions, the steel will corrode within a very short-time frame. Nevertheless, one of the most important advantages of using Magnelis is that it performs at least three times better than normal galvanizing products. Magnelis’ self-healing quality also ensures a perfect protection of the uncoated edges and perforations.

These properties have been assessed by the Technical Research Institute of Sweden, which certified Magnelis’ ability to withstand C5 conditions, the most severe environment. Magnelis has also received a Preliminary Technical Evaluation of Materials performed by the Centre Scientifique et Technique du Bâtiment, in France, and has been certified by a number of external bodies, including the Science Partner and the Deutsches Institut für Bautechnik.

CSP Today: How does ArcelorMittal’s network benefits EPCs in emerging CSP markets?

DR: We have a well-established network of steel distributors all over the world. In fact, our customers are the suppliers of the EPC companies. Therefore, we believe we can help EPCs find the best local distributors, especially in emerging markets with high local content requirements, such as South Africa and Morocco, to name a few.

CSP Today: Does ArcelorMittal provide any sort of warranty attached to the purchase of Magnelis?

DR: Yes, we offer a unique 25-years warranty, which makes us the only provider able to offer such long warranty for a coating product.

CSP Today: What is the price of the product?

DR: The price list of the Magnelis family of products is available here. However, there are many considerations to take into account when calculating the cost of steel structure’s coating since each market and project is different.

Dörte Reinke has more than 20 years’ of experience in the steel industry, all of them working at ArcelorMittal. For the last two, she has been focused on the development of the company’s solar portfolio. 

About ArcelorMittal

ArcelorMittal, the world's leading integrated steel and mining company, supports the move to clean energy generation by offering high-performance steels, advanced metallic coatings, and structural solutions for PV and solar thermal installations. The company also offers tailor-made services such as co-engineering and full project handling.

To know more about the product, please contact Dörte Reinke, Business Development Solar ArcelorMittal.

T: +49 421 648 2958
M: +49 162 233 2958