Hertha Metals built cleaner steel around the industry's least romantic constraint: price

Why it matters

Meroueh is testing whether industrial decarbonization can move faster by beating coal-based steel on cost first.

Hertha Metals founder and CEO Laureen Meroueh has built a one-metric-ton-per-day steel pilot in Conroe, Texas, around a blunt commercial premise: lower-emissions steel has to compete on price before mills will adopt it. Hertha says its furnace can turn iron ore directly into refined liquid steel while cutting operating costs by 25% and emissions by at least 50% compared with conventional U.S. steelmaking.

Those figures remain Hertha's estimates at pilot scale. The sharper detail in a MIT Technology Review profile published September 8 is the compromise Meroueh chose to reach them. Hertha's process still burns natural gas.

That decision fits the founder behind it. Meroueh entered a Florida Atlantic University pilot program at age 12, taking college-level courses in subjects including calculus and ocean wave energy instead of following a conventional secondary-school curriculum. She later earned dual bachelor's degrees in civil and mechanical engineering from the University of Florida, followed by master's and doctoral degrees in mechanical engineering at MIT.

After completing her PhD in 2020, Meroueh led Alchemr, a green-hydrogen developer working on electrolyzers that did not rely on precious metals. She then joined the first cohort of Breakthrough Energy's Innovator Fellows and founded Hertha in March 2022. Meroueh has traced her willingness to start Hertha to growing up as a first-generation Lebanese-American in an entrepreneurial family, where forming a business felt normal rather than exceptional.

One furnace instead of a chain of plants

Conventional steel production usually separates the job into multiple stages. A blast furnace uses coke made from coal to remove oxygen from iron ore and produce molten iron. Further furnaces refine that material into steel. The chain also requires ore preparation, including coking and sintering equipment, and favors particular grades and formats of iron ore.

Hertha's Flex-HERS process combines melting, chemical reduction and carbon adjustment inside a single electric-arc furnace. Electricity supplies heat while natural gas removes oxygen from the molten ore. Hertha says the furnace can accept low-grade ore, fines and waste oxides, then produce liquid steel or high-purity iron without an intermediate iron product passing through another furnace.

Fewer steps could shrink the physical plant, its energy demand and the capital required to build it. Iryna Zenyuk, a University of California, Irvine professor and director of the National Fuel Cell Research Center, told MIT Technology Review that reducing the size of steel production systems could deliver meaningful efficiency gains even before a process reaches zero emissions.

The natural-gas choice gives Hertha access to a readily available U.S. fuel and avoids waiting for a large supply of competitively priced clean hydrogen. It also puts a ceiling on the climate claim. Natural gas produces CO2 when used, and methane released during production and transport must be counted when assessing its full effect. RMI's steel emissions guidance specifically includes fugitive methane from natural-gas supply chains in steel emissions accounting.

Hertha says hydrogen can eventually replace natural gas without a major furnace redesign. Until Hertha operates at commercial scale with independently measured fuel use, ore inputs and upstream methane emissions, the 50% reduction remains a projection rather than a demonstrated plant-wide result.

Meroueh chose deployment speed over a perfect endpoint

Hertha's strategy differs from several well-funded efforts to remove fossil fuels from primary iron production. Boston Metal is developing molten-oxide electrolysis, which uses electricity to split iron oxide and produce liquid metal without direct CO2 emissions. Electra dissolves ore and electrodeposits high-purity iron at relatively low temperatures. Other projects plan to replace coal with hydrogen in direct-reduced-iron plants.

Those routes offer deeper potential emissions cuts. They also depend on cheap clean electricity, hydrogen infrastructure or electrochemical systems reaching industrial throughput. Meroueh has designed Hertha around fuels, furnace components and operating practices that steel producers already understand.

That is a founder's sequencing decision as much as a technical one. Hertha can pursue a lower-carbon process with today's fuel supply, then offer hydrogen as an upgrade if its price falls. The trade creates a product that is easier to pitch to cost-sensitive mills while exposing Hertha to scrutiny from buyers that require near-zero-carbon steel.

A one-ton pilot, then a much harder scale-up

Hertha opened its Conroe headquarters in 2023 and began running the pilot at roughly one metric ton per day in late 2024, according to MIT News. Inc. reported that Meroueh built the pilot for about $5.5 million and reached the one-ton target within months of starting operations.

On July 22, 2025, Hertha announced more than $17 million in funding from Khosla Ventures, Breakthrough Energy Fellows, Pear VC, Clean Energy Ventures and other investors. Inc. reported in June 2026 that Hertha had raised about $20 million, including a U.S. Department of Energy grant.

Rajesh Swaminathan, a partner at investor Khosla Ventures, told MIT Technology Review that Hertha's output was impressive relative to the capital spent.

One metric ton a day remains tiny beside a commercial steel mill. Hertha plans a second facility next to the pilot with annual capacity of about 10,000 metric tons, targeting full output by the end of 2027. The initial product would include high-purity iron used in permanent magnets, giving Meroueh a smaller and potentially higher-value market before Hertha attempts commodity steel volumes.

Meroueh has set a target of 500,000 metric tons per year from another site by 2030. That step is orders of magnitude larger than the Conroe pilot and will test furnace durability, feedstock consistency, energy recovery, product quality and operating cost under continuous industrial conditions.

The commercial test will arrive before the 500,000-ton mill. Hertha needs steelmakers or magnet producers willing to commit to output from the intermediate plant, where customer specifications will carry more weight than pilot demonstrations. The supplied reporting does not establish signed offtake agreements or named customers. Meroueh ultimately plans to integrate the process with existing mills rather than ask steel manufacturers to discard their downstream equipment.

That integration strategy gives incumbents a reason to work with Hertha instead of treating it solely as a replacement threat. Meroueh is asking mills to swap the ore-to-liquid-steel section of production while keeping valuable casting, rolling and finishing assets in service.

Hertha's pitch therefore rests on a deliberately modest starting point for industrial climate technology: make a cleaner process that operators can afford, fit it into plants they already own and preserve a route to hydrogen later. Meroueh has produced enough steel to move the argument out of the laboratory. The next plant has to prove the economics survive the trip.