Sustainable steel for the solar industry

Steel manufacturing accounts for 8% of global energy demand and 7% of energy-related CO2 emissions, according to the International Energy Agency. The World Steel Association says energy use per ton of steel has dropped by 60% since the 1970s and steel is the world’s most recycled material, but there is still room for improvement. pv magazine’s UP initiative looks at opportunities for the industry to be greener, such as integrating solar and energy storage.

October 25, 2024 Mark Hutchins

Image: Nextracker

From pv magazine 10/24

The 2023 pv magazine Award for Sustainability went to steel producer Arcelor Mittal for its XCarb steel product, produced in a 100% renewables-powered electric arc furnace and incorporating a high percentage of recycled material. Arcelor Mittal said it powers the furnaces producing that type of steel by using independently verified clean energy, backed by a guarantee of origin and renewable energy certificates it has purchased. In Sestao, northern Spain, the steelmaker plans to operate the first full-scale zero carbon emissions plant, and Arcelor Mittal wants to achieve full carbon neutrality by 2050.

In Sweden, SSAB is cutting steel’s carbon emissions with its Hybrit process. This method replaces traditional coal or natural gas with hydrogen to remove oxygen from iron ore, emitting only water instead of CO₂. It allows both new steel and scrap material to be processed without emissions. The Swedish business is targeting 2026 for market introduction of its “SSAB Zero” product and said it expects to “largely eliminate carbon dioxide emissions” from all of its operations by 2030.

In 2020, ArcelorMittal announced a zero-emissions-by-2050 target, estimating that achieving this goal could require €30 billion ($33.4 billion) to €40 billion in investment, plus additional costs for the energy infrastructure needed to support the new processes.

Lower-cost competitors may remain in the market, so advancing the low-carbon transition across the industry will require effective policies and innovative approaches by companies. pv magazine’s UP initiative will explore these issues in detail in its November and December 2024 editions.

“The financial costs of realizing carbon-neutral steelmaking are undeniably huge,” said Geert Van Poelvoorde, CEO of Arcelor Mittal Europe Flat Products. “However, with a shift in market conditions brought about by having the right policies in place, European steelmakers will be able to unlock the means to reduce emissions from steel globally.”

Steel and solar

As it goes further down the decarbonization pathway, the steel industry will need solar power in huge quantities. That will constitute a two-way relationship, since steel products are also vital for both solar and energy storage. PV inverters, batteries, trackers, mounting systems, and other components need durable steel to be able to stand up to the elements for 30 years or more.

Tracker companies in particular have taken advantage of various innovations in steel manufacturing and treatment to develop products suitable for different regions and climates, looking at new processes to replace conventional hot-dip galvanization and promising better performance even in harsh climates. Here again, Arcelor Mittal has introduced its Magnelis steel product, with a zinc-aluminum-magnesium coating designed to offer at least triple the corrosion resistance of galvanized steel. Magnelis has already been adopted by several solar tracker manufacturers.

Steel frames are also an increasingly common sight in PV module manufacturing. As PV manufacturing inexorably stretches out to more regions outside of China, some producers find themselves in geographies where an established industry makes steel easier to get hold of than aluminum – the production of which is highly concentrated in China. Though heavier than aluminum, steel is also stiffer and could, in combination with improvements to glass, offer a solution to the issue of structural weaknesses in large-format solar modules.

With aluminum manufacturing a more difficult-to-abate sector, in terms of emissions reduction, the many pathways steel manufacturers are exploring offer a way for solar module makers to reduce their carbon footprint – as they are increasingly required to do in some regions.

Another pv magazine Award winner in 2023, US-based Origami Solar, is looking to take advantage of the ongoing PV manufacturing renaissance and the US Inflation Reduction Act’s bonuses for the use of locally produced content, by driving a switch from aluminum to steel as the preferred material for its PV module frames. The company has estimated that if all of the planned manufacturing capacity coming online in the United States were to take up its steel frames, the move would save up to 10 million tons per year in CO₂ emissions.

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