Decarbonizing an energy system is, in physical terms, a materials problem. Fossil fuel plants extract energy by burning dense fuels and require comparatively modest amounts of metal per megawatt of capacity. Renewable generators invert that logic: they harvest diffuse energy flows from sun and wind, so they must spread large areas of collectors and converters across the landscape, each kilogram of steel, glass and semiconductor doing less work than a tonne of coal. The result is that a renewable-heavy grid is dramatically more material-intensive per unit of electricity than the fossil system it replaces. Copper for cabling and generators, zinc for corrosion-resistant galvanizing of steel structures, silicon for photovoltaic wafers and rare earth elements for permanent magnets all scale directly with installed capacity.

What has been missing, the authors argue, is a rigorous accounting of what the EU’s specific legal commitments imply for these materials. Previous assessments, including work by the European Commission’s Joint Research Centre and the International Energy Agency, offered broad global or sectoral estimates, but the continental mineral demands of legally binding targets remained poorly quantified. The new study closes that gap by constructing three scenario-based projections of solar, onshore wind and offshore wind deployment across the EU27 through 2050, and translating each capacity trajectory into demand for copper, zinc, silicon and rare earth elements using technology-specific material intensities.

The scenarios matter because the three technologies are not interchangeable in their mineral appetites. Solar photovoltaics are dominated by silicon, silver and aluminum, with relatively little exposure to rare earths. Onshore wind turbines use permanent magnets in many modern designs but can also employ geared or doubly-fed generator architectures that reduce or eliminate rare earth content. Offshore wind is different in kind: the harsh marine environment and the premium on reliability and weight favor direct-drive turbines built around permanent magnet synchronous generators, which depend on neodymium, praseodymium, dysprosium and related rare earth elements. Every additional gigawatt of offshore wind therefore locks in a specific and largely non-negotiable rare earth demand.

The study’s most striking finding concerns exactly this lock-in. The researchers show that pathways prioritizing offshore wind maintain rare earth element exposure near full-target levels, at 69.2 kilotonnes, even when solar and onshore wind deployment falls short of their own targets. In other words, because the rare earths are technologically embedded in direct-driven turbine generators rather than being optional add-ons, a strategy that leans on offshore wind cannot shed its rare earth burden by trimming other technologies. The mineral demand follows the turbine design, not the overall ambition level. This asymmetry means that offshore-heavy pathways concentrate supply-chain risk in a small number of elements whose mining and, crucially, midstream processing are geographically concentrated far outside Europe.

The geographic concentration is where the analysis turns from engineering to geopolitics. The paper’s accompanying figures map world reserves of chromium, copper, manganese, molybdenum, nickel, rare earths and zinc across major reserve-holding countries, underscoring that no single region can supply the full basket of transition metals. For rare earths in particular, the bottleneck is less the existence of deposits than the refining and separation capacity needed to turn ore into magnet-grade material, a midstream stage dominated by a handful of suppliers. The authors, who have previously written in Nature that minerals will shape the future geopolitical order, frame the EU’s position as one of structural exposure: the bloc can diversify its turbine suppliers, but not easily the mineral inputs those suppliers all draw upon.

Supply-chain exposure, the study finds, is highly dependent on the chosen technology pathway. A portfolio that balances solar, onshore and offshore wind spreads demand across a wider set of minerals, each with its own reserve distribution and market structure, reducing dependence on any single chokepoint. An offshore-centric pathway, by contrast, delivers high capacity factors and valuable grid services, as other research has shown offshore wind can reduce the total installed capacity needed in zero-emissions grids, but it does so by concentrating risk in rare earths. The scenarios thus present policymakers with an explicit trade-off between the system-level efficiency of offshore wind and the material resilience of a more diversified build-out.

The authors’ central reframing is conceptual as much as quantitative: the clean energy transition should be understood as a continental materials procurement challenge in which mineral security functions as a binding feasibility constraint, on par with financing, grid infrastructure and public acceptance. If the required minerals cannot be procured on schedule, the legally binding targets are not merely delayed but rendered infeasible, regardless of political will or available capital. This shifts the policy question from how much renewable capacity to build toward whether the material inputs for that capacity can be secured, processed and delivered on a 25-year timeline.

To make that feasibility concrete, the paper proposes three institutional responses. First, member states should institutionalize material stress tests in their national energy and climate plans, subjecting deployment targets to the same kind of supply-chain scrutiny that financial regulators apply to bank balance sheets. Second, the EU should establish strategic component reserves, stockpiling not just raw ores but finished components such as permanent magnets and power electronics, where the true vulnerability lies. Third, the bloc should actively secure international midstream processing partnerships, investing in refining capacity in partner countries and diversifying away from single-source dependence. The recommendations echo the direction of the EU’s Critical Raw Materials Act and Net-Zero Industry Act, but the authors argue these instruments must be tied directly to the legally binding deployment targets rather than treated as industrial policy in the abstract.

The timing of the analysis is significant. Global investment in clean energy has surged, with the IEA’s World Energy Investment reports documenting record capital flows into renewables, and the EU’s Fit for 55 package has converted political ambition into binding law. Yet recent modeling of net-zero pathways and warnings in Science that the energy transition needs entirely new materials both point in the same direction as the new study: the physical substrate of decarbonization is finite, geographically uneven and increasingly contested. As the United States and other powers strike bilateral mineral agreements, the competition for transition metals is becoming a defining feature of twenty-first-century statecraft. For the EU, the message of this research is that gigawatts are the visible currency of the energy transition, but kilotonnes of copper, zinc, silicon and rare earths are the hidden ledger on which its climate commitments will ultimately be judged, and that ledger must be balanced starting now.

Subject of Research: Critical mineral demand projections for EU solar and wind energy deployment to 2050

Article Title: From gigawatts to critical mineral demands for EU solar and wind

Article References: Kammen, D. M., Baranowski, M., Jabkowski, P., & Dutta, S. (2026). From gigawatts to critical mineral demands for EU solar and wind. Nature Energy. https://doi.org/10.1038/s41560-026-02147-x

Image Credits: AI Generated

DOI: 10.1038/s41560-026-02147-x

Keywords: critical minerals, rare earth elements, offshore wind, solar energy, European Union, supply chains, energy transition, copper, zinc, silicon, Nature Energy, mineral security