Sustainability discussions about data centre hardware almost always start and finish with carbon. That is reasonable as far as it goes; carbon is the metric being regulated, audited and disclosed. It is also, on its own, a partial view of what a server actually does to the natural systems around it. Every server is also a few kilograms of steel, aluminium, copper, iron, plastics, zinc, brass, rubber and a small but consequential collection of critical raw materials. Each has a measurable environmental footprint distinct from carbon. Each has a different set of options at end of life.

We have added that materials breakdown to the Interact environmental report. Here is what it covers and why.

What's in the report

For every server in a customer estate, the environmental report lists the quantity of each major material in the machine: steel, aluminium, copper, iron, plastics, zinc, brass, lithium and rubber. It also lists the critical raw materials present, in trace amounts but worth flagging separately.

The data source is the Joint Research Council, which informs the EU Commission's work on circular economy and supply chain risk. The Council's materials inventories are publicly available and improve as research expands; the Interact report incorporates updates as they land.

Why bulk materials matter

The major bulk materials in servers (steel, aluminium, copper, iron, zinc, brass) are produced through processes with significant environmental footprints: land use change, deforestation, habitat and biodiversity loss, water pollution, greenhouse gas emissions during smelting. Most of these metals recycle efficiently. The constraint, oddly, is demand. Data on the virgin material content of new servers suggests recycled feedstock is rarely used. Surfacing the material content of installed equipment is one way to push that demand picture in the right direction.

Plastics and rubber

Plastics are what the planetary boundaries literature calls "novel entities", materials alien to natural systems with no biological pathway for breakdown. Approximately 4 million tonnes of plastic enter the oceans annually; only around 9% of all plastic produced has ever been recycled. Plastics recovery is limited by the type of plastic and the cumulative number of times it has been recycled; even compatible compounds typically require a proportion of virgin plastic to maintain quality. Knowing the proportion of plastic in a server estate helps recyclers focus on the material most worth recovering.

Rubber sits in similar territory. Synthetic rubber is a petroleum product, with associated climate, air and water pollution. Natural rubber has its own land use and biodiversity impacts. Neither variant recycles meaningfully; the best second-life options are downcycling into non-slip mats, playground surfaces, astroturf.

Lithium and end of life

Lithium is in dwindling supply globally and in rising demand from the renewable transport and energy sectors. Its extraction is water-intensive and pollution-heavy in the regions where it is mined. There is also a practical end-of-life consideration: lithium increases fire risk during hardware destruction, and lithium fires are difficult to extinguish. Knowing the lithium content of a server estate lets recyclers separate it and process it differently, both for material recovery and for safety.

Critical raw materials

Critical Raw Materials are the substances governments have identified as either in low geological supply or in politically risky supply because they come from a small number of countries. In servers, they appear in trace quantities. They still count. The CRMs typically present in server hardware include Dysprosium, Palladium, Platinum, Antimony, Silicon, Gallium, Germanium, Cobalt, and Lithium.

The complication: mainstream recycling processes tend to destroy CRMs in servers, because the recycling step destroys the amalgams and coatings that hold them. Recovery rates today are correspondingly low. Newer processes including bioleaching and pyrolysis are under development and likely to be more widely available within the next few years. Quantifying CRM content per server creates the dataset that makes those emerging recovery methods commercially viable when they arrive.

What the report enables

A material breakdown changes what a procurement decision is. Three concrete shifts:

  • Decision quality at end of life. Knowing what is in the equipment supports better calls on product life extension, resale into the secondary market, choice of recycler and choice of recycling process.
  • Supplier conversations. Reading the material content alongside the carbon footprint creates a basis for asking suppliers about recycled-feedstock content, take-back schemes, and bonded recovery commitments. Most large procurement functions are starting to want these conversations on the record.
  • Regulatory readiness. CRM disclosure and circular-economy reporting are both moving up the regulatory agenda in the EU and increasingly elsewhere. The organisations with the material data already in hand will move first; everyone else will be playing catch-up.

What comes next

The CEDaCI project (Circular Economy for the Data Centre Industry, NWE Interreg-funded) is publishing further findings on data centre materials usage and environmental impact, including social impact dimensions. We will be integrating the relevant updates into the environmental report as they become available.

Carbon will remain the metric on the headline. The materials underneath it will increasingly determine whether the procurement decision was the right one.