As the digital economy continues to accelerate, the physical footprint underpinning it is growing with equally relentless force. Modern, high-density data center campuses are expanding in size and volume across the globe, facilitating the development of next-gen tech – from AI workloads to cloud computing and enterprise applications. But as the data center ecosystem continues to scale, so too does scrutiny over its environmental impact.

Traditionally, sustainability conversations across the industry have focused in on operational efficiency – scrutinizing renewable energy sourcing, advanced cooling systems, and power usage effectiveness (PUE). While these remain critical, as complexity and impact grow with the rapid spread of facilities, today’s sustainability discourse demands a more holistic approach.

Right under the noses – and feet – of the industry sits a quieter but equally critical consideration for building genuinely environmentally conscious facilities: material choices.

Today, the materials used to construct data centers – and the carbon embedded within them before a single server is switched on – are becoming central to sustainability strategies. And in this evolving landscape, structural steel is emerging from the background as a foundational solution.

Sean Smith, market development manager at New Millennium, believes this shift represents a fundamental change in how modern data center projects are planned, designed, and delivered:

“Hyperscale developers are moving sustainability requirements upstream into structural specifications as corporate net zero commitments tighten and eco-conscious financing terms grow more demanding,” he explains. “In this environment, every structural choice is a carbon choice.”

The central sustainability challenge for the industry today is no longer simply reducing emissions – it’s understanding where they originate.

Built-in carbon, ready-made challenges

Measurable, manageable, and visible: operational carbon, tied to energy consumption, has long dominated the environmental narrative. It can be optimized over time through efficiency improvements and renewable energy procurement, yet embodied carbon is a different story.

“Operational energy draws most of the attention,” says Smith, “but the carbon baked into a facility’s structure is fixed at the point of procurement and cannot be offset or optimized away after the fact.”

Embodied carbon is locked in at the point of construction, and this distinction is critical. Once a facility has been built, its structural emissions are effectively permanent, meaning no amount of innovation or optimization can reverse the effects. This reality is driving a new urgency around material selection – particularly for high-volume components such as structural steel.

As one of the most widely used materials in hyperscale construction, steel represents a significant opportunity for meaningful emissions reductions. Even incremental improvements in its carbon intensity can translate into substantial project-level gains.

“The structural steel frame is one of the highest volume materials on any hyperscale project,” notes Smith. “That means even modest improvements in carbon intensity deliver large absolute reductions.”

A circular advantage

At the heart of this shift is the idea that not all steel is created equal. Traditional blast furnace steelmaking relies heavily on raw materials such as iron ore and coal, resulting in high levels of greenhouse gas emissions. In contrast, electric arc furnace (EAF) technology uses recycled scrap metal as its primary input, dramatically reducing its environmental footprint.

Steel Dynamics, Inc. (SDI), New Millennium’s parent company, has built its entire operation around this alternative model. With an average of 88 percent recycled content as input across its steel mills, SDI's EAF steel production generates roughly one third of the greenhouse gas emissions associated with conventional methods – delivering genuine positive impact.

“Embodied carbon in our products is addressed at the source before a single beam is rolled,” explains Smith.

This approach is part of a broader circular manufacturing model that connects recycling, steel production, and fabrication into a closed-loop system. Scrap metal collected today becomes the structural framework of tomorrow’s facilities.

Over a recent two-year period, this system processed more than 41 million tons of recycled ferrous scrap – diverting waste from landfill while reducing demand for energy-intensive raw production.

And the implications extend far beyond environmental metrics. For developers, it means access to a supply chain with built-in sustainability, rather than retrofitting to meet increasingly stringent targets against the clock.

Renewable momentum

While recycled content plays a crucial role, it’s only part of the equation. The energy used in steel production also has a significant impact on its overall carbon profile. In response, SDI is investing in renewable and emission-free energy integration across its operations.

By 2025, the company had already achieved 11 percent renewable electricity usage across its steel mills – exceeding its initial 2025 target of 10 percent. It is now targeting 30 percent by 2030, supported by a major wind energy agreement that generates 1.1 million MWh annually.

“As renewable and emission-free electricity use grows, the Scope 2 emissions embedded in our products decline automatically,” says Smith. “That happens without any additional action required from the project team.”

This built-in progress represents a crucial strategic advantage. It effectively evens out the decarbonization burden by shifting some of the pressure up the design and deployment chain, and embedding sustainability into the foundational materials themselves rather than relying solely on operational strategies.

Data-driven sustainability

Despite its importance, embodied carbon has historically been overlooked in data center construction. Smith explains:

“For years, embodied carbon was invisible in sustainability reporting because disclosure was voluntary and assessment tools were inconsistent. The focus defaulted to what could be metered and billed.”

But this is changing thanks to industry frameworks such as Leadership in Energy and Environmental Design (LEED) and Building Research Establishment Environmental Assessment Methodology (BREEAM), alongside growing demand for Environmental Product Declarations (EPDs), which are delivering material-level emissions data to the procurement process to spotlight what previously fell under the radar, and ensure sustainability becomes an actionable non-negotiable.

“Environmental product declarations and third-party verified emissions data are becoming table stakes, not differentiators,” adds Smith.

This shift is reshaping expectations across the supply chain. Developers, investors, and regulators are demanding credible, verifiable data that will hold up under scrutiny – particularly as sustainability reporting becomes more closely tied to financial performance and access to capital.

SDI’s science-based greenhouse gas targets, aligned with the Paris Agreement temperature goal of 1.5°C (34.7°F), provide a level of assurance that’s becoming increasingly essential against this backdrop. For New Millennium’s customers, this translates into documentation that supports everything from regulatory compliance to investor ESG evaluations.

The financing factor

Sustainability has quickly shifted beyond an environmental consideration and into a financial one, too. The rise of sustainability-linked loans and bonds, plus ESG-driven investment criteria is fundamentally changing how data center projects are funded. Material choices now have direct implications for access to investment and the cost of financing.

“Verified sustainability credentials support LEED credit documentation, eco-conscious bond eligibility, and corporate ESG disclosures,” explains Smith. “All of which have real commercial impact.”

At the same time, hyperscale tenants are bringing their own sustainability commitments into the equation.

With Scope 3 emissions – those associated with supply chains and leased assets – under the microscope, the embodied carbon of a facility is becoming a factor in leasing decisions.

This creates a powerful incentive for developers to prioritize low-carbon materials from the outset. And certification systems are evolving in parallel, placing greater emphasis on embodied carbon alongside operational efficiency.

Procurement teams are responding by requesting detailed material data earlier in the design process than ever before. “The conversation is happening sooner,” adds Smith. “And with greater urgency.”

Engineering opportunity

With this complex web of challenges comes an equal number of opportunities. Steel offers unique advantages in the transition toward more sustainable construction. Its strength, durability, and recyclability make it inherently suited to circular economy principles – but continued innovation is key.

“The most impactful near-term gains will come from continuing to decarbonize the manufacturing process itself,” says Smith. “Expanding renewable and emission-free electricity use, improving EAF efficiency, and advancing scrap sorting technology.”

These efforts are already delivering measurable results. Since 2022, SDI has reduced its greenhouse gas emissions intensity by 14 percent. This is a significant step toward its 2030 Global Steel Climate Council (GSCC) certified emissions intensity target of 0.80 metric tons of CO₂e per metric ton of hot rolled steel produced. Crucially, these improvements are not isolated – they can be felt across the product chain.

For data center developers, this means that specifying low-carbon steel today doesn’t have to represent a one-time decision on the checklist, but a meaningful step into a continuously improving sustainability chain.

A new kind of partnership

As data-driven sustainability moves up the priority list, relationships across the construction ecosystem must evolve in response. The traditional transactional model – where materials are specified and delivered with limited collaboration – is fading in favor of a more integrated approach.

Smith sees a future where material producers act as strategic partners in the decarbonization process: “The relationship will shift from transactional to strategic and producers will function as emissions data partners.”

This includes providing project-specific information on recycled content, EPD documentation, and extends to forward-looking carbon intensity projections that can be incorporated into lifecycle assessments. Such collaboration is essential as developers work to meet increasingly stringent targets and navigate a rapidly changing, high-stakes regulatory landscape.

“Developers will increasingly favor supply chains with verified, science-based commitments over those with self-reported claims,” says Smith.

The big picture

As data centers continue to scale at breakneck speed, their environmental impact will rightly remain under close scrutiny. Simultaneously meeting the demands of an increasingly digital world while aligning with global environmental goals demands an integrated, holistic approach that considers not only how facilities operate, but how they’re built.

Sustainable materials are quickly becoming a foundational element of responsible infrastructure development. And in many ways, they represent one of the most immediate opportunities for meaningful change.

Unlike operational systems, which may take years to optimize, material choices deliver instant measurable impact, setting the baseline for a facility’s carbon footprint from day one, making them increasingly indispensable in the industry’s continued growth trajectory.

As Smith concludes: “every structural decision carries weight – not just in terms of performance, but in terms of carbon.”

Read New Millennium's latest eBook, Constructing the data center, here.

For more on Steel Dynamics, Inc.’s commitment to decarbonization, you can visit https://www.steeldynamics.com/valuing-the-environment/.

Please contact Sean Smith to request more information on New Millennium’s structural steel solutions for your data center construction needs. 618-694-5610 || [email protected]