Schott produces ‘greener’ optical glass with 100% hydrogen…

26 Apr 2024

…and Coherent announces “sustainability milestones” to mark Earth Day on 22 April.

The next milestone on the way to climate-neutral production has been reached: After successfully testing glass production with 100 percent hydrogen on a laboratory scale last spring, the technology group Schott has now completed the much anticipated industrial-scale application.

For three days, the Mainz-based specialty glass maker melted optical glass in a furnace using the new technology for the first time – exclusively heated by hydrogen, completely free of natural gas. So far, Schott has been conducting its tests with grey hydrogen because green hydrogen, produced from renewable energies, is not yet available in sufficient quantities. The large-scale test received excellent marks, and the quality of the glass is now being analyzed.

“The test with 100 percent hydrogen is pioneering work for the specialty glass industry. If the tests show that the quality of the glass is also right and the glass properties remain unchanged, hydrogen would indeed be a suitable technology option,” said Schott project manager Dr. Lenka Deneke.

The test manager emphasized that the experience gained from last year’s tank tests with an initial 35 percent hydrogen-by-volume helped with this success, but also asserts that there are still many unanswered questions requiring further research. For example: How does the use of hydrogen impact the complex melting processes, and therein, the quality of different products?

To address these questions, Schott chose an optical glass as the first test product. Background: The technology group manufactures over 100 types of optical glass from high-quality raw materials for various applications, such as consumer goods and measurement technology, as well as optical systems in research and development. The challenge is that the glass must have the highest homogeneity and transmission properties. This also applies to the molten glass, which undergoes strict quality testing.

If the glass meets the high product requirements, it will be sent to the customer. “We would then have confirmation that the use of 100 percent hydrogen instead of fossil fuels delivers the same quality under industrial conditions,” said Deneke. A permanent changeover would then also require further long-term tests and a continuous supply via a hydrogen pipeline.

Schott says it has already achieved the switch to 100 percent green electricity, and energy efficiency is being continuously and systematically increased. The technology change is primarily about replacing natural gas for the operation of the furnaces. Either through electrification with green electricity or in future through the use of green hydrogen.

…and Coherent announces ‘sustainability milestones’

In the same vein, laser giant Coherent has announced that the company is now obtaining approximately 70% of its global electricity needs from renewable energy sources. The firm made the statement on Monday in support of Earth Day 2024 (22 April).

In total, this represents over 500 million kWh of renewable electricity per year, thereby avoiding more than 250,000 metric tons of CO₂ emissions annually. Coherent has set “as a top priority” the reduction of its carbon footprint across its global operations.

“At Coherent, sustainability is an all-hands issue. We encourage -- in fact, we expect -- every one of our 25,000 employees to participate and contribute to the Coherent Lean System through initiatives that attack waste in all of its forms across our enterprise,” commented Bob Daly, Vice President, Global Lean Transformation.

“Even better than using renewable energy is using less energy by training and certifying our employees across several tiers of Lean Six Sigma certifications that focus on projects to identify and eliminate waste in our processes. Driving our Lean principles is intimately intertwined with our sustainability ambitions,” he said.

Since its inception in 2023, the Coherent Lean System has completed projects that it says will result in 2.5 million kWh of energy savings per year. Coherent is also working to eliminate fossil fuel usage in its facilities. For example, its Highyag facility in Kleinmachnow, Germany, installed a heat pump in 2023 to help reduce Scope 1 gas emissions and set a goal to decrease gas emissions by 65% in 2024.