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Protecting steel structures in CSP plants: a different approach – Interview with Dörte Reinke

Steel is widely used in CSP (Concentrating Solar Power) 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 (Capital Expenditure) of a plant, a product that increases its lifetime will result in substantial cost savings for CSP developers.

That is precisely what Magnelis^®, our revolutionary coating system for steel, aims to do. According to Dörte Reinke, Business Development Manager Solar at ArcelorMittal Europe – Flat Products, “this metallic coating system offers protection in the harshest environments.”

CSP Today* spoke to Dörte to find out more about the product’s characteristics.

You can find the full interview below and on the CSP Today website.
Happy reading!  

CSP Today: What exactly is Magnelis^®?
Dörte Reinke: A few years ago we 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 galvanising products.

CSP Today: How does using Magnelis^® impact CSP plants?
Dörte: 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 galvanising 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. At the same time, 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 galvanising companies around to complete the coating process.
In the second process, which is called pre-galvanisation, 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 galvanisation 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?
Dörte: 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?
Dörte: 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?
Dörte: 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 this year. 

CSP Today: What impact could Magnelis^® have on the lifespan of the steel structures in CSP plants?
Dörte: It very much depends on the market. If you have very severe climatic conditions, the steel will corrode within a very short timeframe. Nevertheless, one of the most important advantages of using Magnelis^® is that it performs at least three times better than normal galvanising 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?
Dörte: 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 guarantee attached to the purchase of Magnelis^®?
Dörte: Yes, we offer a unique 25-years guarantee, which makes us the only provider able to offer such a long guarantee for a coating product.