Solar and Wind Energy Minerals

Solar photovoltaic and wind energy systems are the fastest-growing electricity generation technologies in the world, and together they account for the majority of new power capacity additions globally. While these technologies produce clean electricity during operation, their manufacturing depends on a substantial and growing volume of critical minerals. From the polysilicon in solar cells to the rare earth magnets in wind turbine generators, the clean energy transition is fundamentally a mineral-intensive endeavor.

Solar Photovoltaics: Silicon, Silver, and Beyond

Crystalline silicon solar cells dominate the global photovoltaic market, accounting for over 95 percent of annual installations. The manufacturing process begins with metallurgical-grade silicon, refined from quartz sand, which is further purified into polysilicon with a purity of 99.9999 percent or higher. This polysilicon is melted and solidified into ingots, sliced into wafers, and processed into functioning solar cells through doping, passivation, and metallization steps. China controls approximately 80 percent of global polysilicon production and an even larger share of wafer, cell, and module manufacturing.

Silver is the second most critical mineral in crystalline silicon photovoltaics. Silver paste is screen-printed onto solar cells to form the conductive grid that carries generated current to the external circuit. A typical solar cell uses 10 to 20 milligrams of silver, but at hundreds of gigawatts of annual installation, the cumulative silver demand from the solar industry has grown to represent over 15 percent of total global silver consumption. Rising silver prices have incentivized thinner paste lines and alternative metallization techniques, but no commercially viable full substitute for silver has yet been adopted at scale.

Thin-film photovoltaic technologies, while representing a smaller market share, depend on their own set of critical minerals. Cadmium telluride (CdTe) solar cells, manufactured primarily by First Solar, require tellurium, a rare byproduct of copper refining with annual global production of only about 500 metric tons. Copper indium gallium selenide (CIGS) thin films require indium, gallium, and selenium, all of which face supply concentration risks. The growth of thin-film deployment is directly constrained by the availability of these niche minerals.

Wind Energy: Rare Earths, Copper, and Steel

Wind turbines are large-scale electromechanical systems that convert kinetic wind energy into electricity through spinning rotors connected to generators. The mineral intensity of a wind turbine depends on its design, particularly the generator type. Conventional geared turbines use copper-wound electromagnetic generators that require substantial quantities of copper but relatively few critical minerals. Direct-drive turbines, which eliminate the gearbox by using large-diameter permanent magnet generators, consume 600 to 700 kilograms of neodymium-iron-boron magnets per megawatt of capacity.

Direct-drive designs are increasingly favored for offshore wind applications because the elimination of the gearbox reduces mechanical complexity, improves reliability, and lowers maintenance costs in hard-to-access marine environments. This technological preference has profound implications for rare earth demand. Global offshore wind capacity is projected to grow from roughly 60 gigawatts in 2023 to over 300 gigawatts by 2030, with the majority using direct-drive permanent magnet generators. The rare earth content of this expansion alone could reach 100,000 to 200,000 metric tons of NdFeB magnets, straining a supply chain already stretched by EV motor demand.

Beyond magnets, wind turbines consume large quantities of steel (for towers and foundations), copper (for cabling and generators), zinc (for galvanizing), fiberglass and carbon fiber (for blades), and concrete (for onshore foundations). A single 5-megawatt offshore turbine may contain 150 to 200 metric tons of steel, 5 to 8 metric tons of copper, and hundreds of kilograms of rare earth magnets. The sheer volume of material required for a global buildout of wind capacity underscores the importance of stable, diversified mineral supply chains.

Copper: The Conductor Connecting Everything

Copper is not a rare mineral, but it is critical to every aspect of renewable energy infrastructure. Solar installations require copper wiring for module interconnections, inverters, and grid connections. Wind farms use copper in generator windings, power cables, and transformers. Offshore wind installations are particularly copper-intensive due to the long submarine cables needed to transmit power to shore. Total copper demand from renewable energy is projected to grow from roughly 1.5 million metric tons per year in 2023 to over 3 million metric tons by 2030, competing with growing demand from EVs, data centers, and grid infrastructure.

Supply Chain Concentration and Risks

The solar supply chain is the most geographically concentrated in all of renewable energy. China dominates polysilicon production, wafer manufacturing, cell fabrication, and module assembly. The Xinjiang region of China has been a particularly significant production base, raising concerns about forced labor that led to the US Uyghur Forced Labor Prevention Act restrictions on solar imports. Diversifying solar manufacturing has become a priority for the United States, European Union, and India, but building competitive supply chains outside China requires massive capital investment and years of development.

Wind turbine manufacturing is more geographically distributed, with major producers in China (Goldwind, Envision), Europe (Vestas, Siemens Gamesa), and the United States (GE Vernova). However, the rare earth magnet supply chain feeding these manufacturers remains overwhelmingly Chinese. Turbine OEMs are increasingly exploring magnet-free generator designs, including electrically excited synchronous generators and high-temperature superconducting generators, but these alternatives have not yet achieved the cost and reliability benchmarks needed for mainstream adoption.

Recycling and End-of-Life Considerations

As the first generation of utility-scale solar and wind installations approaches decommissioning age, end-of-life mineral recovery is becoming an important consideration. Solar panel recycling can recover silicon, silver, copper, and aluminum, though the economics remain challenging at current commodity prices. Wind turbine decommissioning can recover steel, copper, and potentially rare earth magnets, though blade recycling (primarily fiberglass composite) remains a significant waste management challenge. Establishing efficient recycling infrastructure now will determine whether the minerals embedded in today's renewable energy installations become a future secondary supply source or end up in landfills.