Green steel ‘cheaper’ than conventional, says Hertha

Hertha Metals says it has validated a single-step process that is cheaper, more energy efficient and as scalable as conventional methods.

The US-based company has been operating a continuous one-tonne-per-day pilot plant since late 2024, claiming to convert low-grade iron ore directly into molten steel or high-purity iron in a single step. It is claimed to be 30% more energy efficient and significantly cheaper.

The plant makes use of low-purity ores (<60%), iron ore fines, and millscale as raw material inputs. It is powered by natural gas but offers the option of using hydrogen without any hardware modifications, potentially enabling up to 98% emissions reductions.

According to the company, the Hertha system integrates directly into existing steel mills, avoiding the need for entirely new facilities. Its modular design enables plants as small as 500,000t/yr to operate profitably.

The company plans to break ground on a new production facility in January 2026, which will have a capacity of more than 9,000t/yr, initially supplying high-purity iron (99.97+% purity) to the American rare-earth magnet market.