The increasing deployment of solar energy systems has put a spotlight on the materials that make photovoltaic modules possible. Among those materials, tellurium stands out as a critical, relatively rare element used in one of the major thin-film technologies. Understanding the trajectory of this element — from its geological occurrence and supply constraints to its role in advanced cell architectures and recycling strategies — is essential for predicting how the solar industry will evolve over the next decades. This article explores the technical, economic and environmental dimensions that will shape the future of tellurium in solar panel production.
The role of tellurium in photovoltaic technologies
Tellurium is the key component in cadmium telluride (CdTe) solar cells, which represent the second-largest commercial thin-film technology after amorphous silicon. CdTe modules are attractive because they can achieve competitive photovoltaics performance with relatively low manufacturing costs and high production throughput. The CdTe technology benefits from a simple manufacturing process—often coating large-area glass substrates with thin layers of cadmium and tellurium compounds and then activating them via thermal treatment. This approach enables rapid scaling and lower energy payback times compared to some crystalline silicon processes.
Modern CdTe cells have improved optical management, better contact engineering and advanced doping strategies that raise cell efficiencies while reducing material consumption. Laboratory and commercial modules now routinely reach conversion efficiencies that make them competitive with conventional silicon modules on a levelized cost of energy basis. Despite such merits, the broader adoption of CdTe-based panels depends on the availability and cost stability of tellurium as well as regulatory and market attitudes toward cadmium-containing products.
Resources, supply constraints and market dynamics
From a geological perspective, tellurium is not mined directly as a primary ore in most cases. Instead, it is recovered as a byproduct during the refining of copper and sometimes from anode slimes in electrorefining processes. This coupling of tellurium production to copper demand means the supply of tellurium does not respond directly to changes in PV demand, creating potential constraints if CdTe deployment grows rapidly.
Estimates of global tellurium reserves and annual production point to a limited base relative to metals like copper or aluminum. Because of that relative scarcity, price volatility and concentration of refining capacity can become significant factors in the levelized cost modeling for CdTe technologies. Market participants must contend with scenarios in which tellurium supply tightens as other industries expand their use of it, or where geopolitical and trade factors affect access to concentrated refining facilities.
- Geographical concentration: Some countries and facilities play outsized roles in tellurium recovery; supply risks can be localized.
- Byproduct dependence: Tellurium availability is linked to copper mining economics, which complicates long-term forecasting.
- Demand competition: Emerging applications in electronics, thermoelectrics and specialty alloys can assert upward pressure on pricing.
Technological innovations reducing material intensity
One clear path to easing pressure on tellurium supply is to reduce the amount required per watt of installed capacity. Research and industrial process improvements aim to minimize the thickness of active layers, enhance light absorption, and recover performance losses without proportional increases in material use. The characterization of absorber layers, use of advanced deposition techniques, and interface engineering all contribute to lower material intensity per cell.
Advancements in manufacturing and cell design also address the limitations of thin-film production. Techniques such as sputtering optimizations, close-spaced sublimation refinements and novel roll-to-roll approaches can deliver uniform absorbers with sub-micron tellurium layers. In parallel, device-level innovations—like passivation of grain boundaries, buffer layer tuning and back-contact improvements—allow manufacturers to extract more performance from less material. The combination of process yield enhancement and thickness reduction is a crucial lever for keeping CdTe competitive even if raw tellurium supply tightens.
Recycling, circular economy and supply augmentation
Recycling of end-of-life modules and process scrap recovery offers a pragmatic and sustainable route to extending the effective supply of tellurium. Because tellurium concentrations in CdTe modules are orders of magnitude higher than in average crustal rock, economically viable recovery from panels is feasible if collection and processing infrastructure is in place. A robust circular approach not only reduces dependence on primary byproduct sources but also mitigates environmental risks associated with cadmium-containing waste streams.
Two parallel recycling streams can be envisioned: industrial recycling of manufacturing scrap (high purity, high recovery rates) and post-consumer recycling (lower concentration, higher logistics complexity). Scaling post-consumer recycling will require policy frameworks that incentivize take-back programs, extended producer responsibility, and investments in chemical processing facilities capable of separating and purifying cadmium and tellurium for reuse. Innovations in hydrometallurgical and pyrometallurgical recovery processes—along with modular, localized recycling hubs—can further improve the economics and reduce transportation emissions.
Beyond recycling, researchers are exploring unconventional sources and improved extraction from existing anode slimes and copper refinery byproducts. New leaching chemistries, solvent extraction techniques and electrochemical separation methods could increase tellurium yields from current industrial streams, thereby augmenting supply without expanding primary mining operations.
Competition from alternative materials and technologies
CdTe does not exist in isolation; it competes with crystalline silicon, CIGS (copper indium gallium selenide), perovskites and tandem architectures for market share. Silicon remains dominant due to abundant raw materials and well-established manufacturing. Perovskites and tandem cells promise very high efficiencies and potentially lower material costs, but they face stability and scaling challenges. Materials like indium and gallium used in alternative thin films also face supply constraints, creating a broader resource nexus in the solar industry.
If perovskite-on-silicon tandems reach commercial maturity and large-scale production, the relative role of CdTe could shrink. Conversely, improvements in CdTe manufacturing and recycling could preserve or grow its niche in utility-scale installations and specific climates where its temperature coefficients or spectral response are advantageous. The competitive landscape will be determined by a mix of efficiency gains, manufacturing scalability, raw material economics and regulatory pathways for materials containing heavy metals.
Environmental, regulatory and social considerations
The environmental profile of tellurium-containing modules hinges largely on the presence of cadmium. While CdTe modules lock cadmium into a stable compound that is less mobile than elemental cadmium, concerns persist among regulators and the public. Life cycle assessments typically show CdTe panels have low overall environmental impact per unit energy generated, but sensitive end-of-life management is essential to prevent local contamination risks.
Regulatory regimes that require secure recycling, clear labeling and strict transportation standards can help build public trust. Transparent demonstration projects, independent testing and third-party certification will be important to demonstrate that CdTe modules can be deployed safely at large scale. Community engagement and clear communication about recycling pathways and safety protocols are also central to broader acceptance.
Economic and geopolitical implications
Tellurium’s byproduct nature and uneven global refining footprint create geopolitical angles that solar manufacturers and policymakers must consider. Dependence on a handful of refining centers can lead to supply chain vulnerabilities similar to those seen in other critical materials. National strategies that encourage domestic recovery from copper operations, invest in recycling infrastructure, or incentivize alternative materials can reduce exposure to external shocks.
From an economic perspective, the volatility of tellurium prices could influence investment decisions for new CdTe capacity. Long-term offtake agreements, supply diversification, and vertical integration (including recycling operations) are practical business responses. On the policy side, support for research into low-tellurium or tellurium-free alternatives, combined with subsidies or credits for circular manufacturing, could shape the technology mix that ultimately dominates the market.
Research directions and likely scenarios
Looking ahead, several research pathways and deployment scenarios could define the role of tellurium in the solar sector:
- Moderate growth with strong recycling: CdTe continues to grow modestly, supported by improved manufacturing efficiency and high recycling rates that stabilize scarcity concerns.
- High-growth bottleneck: Rapid expansion of CdTe capacity faces raw material constraints, leading to price spikes and incentivizing substitution or aggressive recycling scale-up.
- Displacement by tandems: Perovskite or other tandem technologies achieve mass commercialization, reducing demand pressure on tellurium while preserving niche markets for CdTe.
Continued investment in process innovation, better materials utilization and policy frameworks that reward circular approaches will be pivotal. For researchers and manufacturers, the twin goals of higher module efficiency and lower material intensity remain primary technical drivers. At the same time, integrated strategies around collection and reuse will address supply risk and environmental stewardship.
Policy and industry actions to shape the future
Policymakers can influence the trajectory of tellurium use through targeted measures: incentives for recycling, funding for recovery technology R&D, standards for module take-back and support for diversified supply chains. Industry can respond by building vertically integrated operations that link module manufacturing with recycling and raw-material recovery, negotiating strategic partnerships with copper refiners, and investing in material-saving process technologies.
The success of tellurium-based solar solutions will hinge on coordination across the value chain: miners and refiners improving recovery rates, manufacturers reducing material per watt, and governments fostering the infrastructure for safe end-of-life handling. Collectively these actions can strengthen the role of CdTe in the renewable energy mix without exacerbating resource constraints or environmental risks.
