Coatings

Photovoltaic film coatings

Photovoltaic (PV) film coatings are essential for enhancing the efficiency, durability, and performance of solar panels. These coatings improve light absorption, electrical conductivity, and weather resistance, ensuring that PV systems operate effectively over their lifespan.

Several critical minerals are used in PV coatings, particularly in thin-film solar technologies:

• Indium – A key component in indium tin oxide (ITO) coatings, used for transparent conductive layers that improve electrical performance and light transmission in solar cells.

• Gallium – Enhances the efficiency of thin-film solar cells, particularly in copper indium gallium selenide (CIGS) technology, by optimising the energy bandgap for better sunlight absorption.

• Tellurium – A crucial element in cadmium telluride (CdTe) solar cells, enabling high efficiency and cost-effective production in large-scale thin-film PV applications.

PV system assembly and performance

c-Si cell manufacturing

The performance and efficiency of photovoltaic (PV) systems depend on the quality of materials used in their assembly, particularly in crystalline silicon (c-Si) cell manufacturing, which dominates the solar industry. These materials play a crucial role in enhancing electrical conductivity, energy conversion efficiency, and overall system reliability, ensuring higher energy yields, longer lifespan, and improved efficiency in solar technology. As demand for renewable energy continues to grow, securing a stable supply of these critical minerals is essential for the sustained advancement of solar power.

Key critical minerals in c-Si solar cell manufacturing include:

• Silicon – The fundamental material in solar wafers, forming the semiconductor base of most PV cells. It enables efficient light absorption and electron flow for electricity generation.

• Silver – Used in conductive pastes for solar cell contacts, ensuring efficient electron transfer and improving energy output. Silver’s high conductivity makes it a crucial component for boosting PV cell efficiency.

• Indium – Found in transparent conductive coatings, particularly in indium tin oxide (ITO) layers, which enhance light transmission and electrical conductivity in high-performance solar cells.

Thin film CIGS panel manufacturing

Copper indium gallium selenide (CIGS) thin-film solar panels are known for their high efficiency, flexibility, and lightweight design, making them a key alternative to traditional crystalline silicon (c-Si) solar cells. These panels rely on a combination of critical minerals to enhance light absorption, conductivity, and durability, while cadmium telluride (CdTe) technology offers low manufacturing costs and high scalability, driving the expansion of thin-film solar energy. However, securing a sustainable supply of tellurium, cadmium, and other essential minerals is crucial for maintaining the growth and long-term viability of these advanced solar technologies.

Key materials used in CIGS panel manufacturing include:

• Silicon – Used in substrates and encapsulation materials, providing structural stability and protection for thin-film solar cells.

• Copper – A key element in CIGS absorber layers, enabling efficient charge collection and transport within the solar cell.

• Selenium – Enhances light absorption and stabilises the CIGS semiconductor, improving energy conversion efficiency.

• Indium – Used in CIGS thin films to fine-tune the semiconductor’s electronic properties, optimising performance.

• Gallium – Adjusts the bandgap energy of CIGS cells, allowing for better sunlight absorption and improved efficiency.

• Tellurium – Occasionally used in buffer layers or alternative formulations to enhance stability and durability.

Thin film CdTe panel manufacturing

Cadmium telluride (CdTe) thin-film solar panels are among the most efficient, cost-effective, and scalable photovoltaic (PV) technologies, particularly for large-scale solar farms. They offer high energy conversion efficiency, excellent performance in low-light conditions, and strong resistance to environmental degradation, making them a key driver in the expansion of solar energy. Their low manufacturing costs further enhance their appeal, but securing a sustainable supply of tellurium and cadmium is crucial for maintaining the growth and long-term viability of this thin-film solar technology.

Key materials used in CdTe panel manufacturing include:

• Silicon – Used in glass substrates and encapsulation, providing structural support and protecting the thin-film layers from environmental damage.

• Cadmium – Forms the cadmium telluride (CdTe) semiconductor layer, which is responsible for light absorption and electron movement to generate electricity.

• Tellurium – Combined with cadmium to create CdTe, enabling a high-efficiency solar absorber that converts sunlight into electricity with minimal material usage.

• Indium – Used in transparent conductive coatings, such as indium tin oxide (ITO) layers, to improve electrical conductivity and enhance light transmission.

CdTe technology is known for its low manufacturing costs and high scalability, making it a key driver in the expansion of solar energy. However, securing a sustainable supply of tellurium and cadmium is crucial for maintaining the growth and viability of this thin-film solar technology.

Balance of system (BOS)

The Balance of System (BOS) includes all components of a photovoltaic (PV) system aside from the solar panels, such as wiring, inverters, mounting structures, and electrical connections, which are crucial for efficient power transmission, system stability, and long-term performance. As solar energy deployment expands, securing a stable copper supply is essential to maintaining a reliable and efficient solar power infrastructure.

Copper is a key material in BOS due to its high electrical conductivity, durability, and resistance to corrosion. It plays several critical roles:

• Cabling and wiring – Copper is widely used in solar power cables to minimise energy losses during transmission from PV panels to inverters and the grid.

• Earthing and grounding systems – Copper’s superior conductivity ensures effective grounding and protection against electrical faults.

• Inverters and transformers – Copper is essential for winding coils and electrical contacts, improving energy conversion from DC (direct current) to AC (alternating current) for grid integration.

• Junction boxes and connectors – Used in busbars and connectors, copper ensures reliable electrical connections, reducing resistance and improving system efficiency.

PV system components

Frame

The frame is a crucial component of a photovoltaic (PV) system, providing structural support, durability, and protection for solar panels. It ensures the mechanical stability of the panel, enabling it to withstand environmental factors such as wind, snow, and thermal expansion.

Aluminium is the preferred material for PV frames due to its lightweight nature, corrosion resistance, and strength. It allows for easy installation while maintaining long-term durability, making it essential for ensuring the reliability and longevity of solar energy systems.

As solar energy deployment expands, ensuring a stable aluminium supply is vital for maintaining the scalability and sustainability of the industry.

Connectors

Connectors are essential in photovoltaic (PV) systems, ensuring secure and efficient electrical connections between solar panels, inverters, and other components. High-quality connectors minimise power losses, improve electrical conductivity, and enhance system reliability and safety. As solar power adoption grows, securing a stable supply of copper and aluminium is crucial for maintaining long-term performance and efficiency in solar installations.

• Copper – Widely used in electrical connectors due to its high conductivity, durability, and resistance to overheating, ensuring efficient power transmission.

• Aluminium – A lightweight alternative to copper, often used in high-voltage transmission components to reduce costs while maintaining electrical efficiency.

Busbar, tabbing and solders

Busbars, tabbing, and solders are essential components in photovoltaic (PV) systems, facilitating efficient electrical connections within solar cells and modules. These elements ensure the smooth flow of electricity, enhance system reliability, and minimise energy losses. As solar technology advances, securing a stable supply of key metals, particularly tin and copper, is crucial for maintaining the efficiency, performance, and longevity of solar power systems.

• Tin – Used in solders to create strong, conductive joints between solar cells, ensuring reliable electrical connections.

• Copper – A key material in busbars and tabbing ribbons, offers high conductivity and efficient power distribution across the PV module.

Improved efficiency

Zinc plays an important role in enhancing the efficiency and durability of photovoltaic (PV) systems. While not a primary semiconductor material, it is used in various applications to improve performance, stability, and longevity. As solar technology advances, zinc-based materials continue to contribute to efficiency, reliability, and durability, supporting the long-term sustainability of solar energy systems.

• Zinc Oxide (ZnO) as a Transparent Conductive Layer – Used in thin-film solar cells, ZnO acts as a transparent conductive oxide (TCO), improving light transmission and electrical conductivity while protecting underlying layers from degradation.

• Anti-Corrosion Coatings – Zinc coatings, such as galvanised steel, protect mounting structures and frames from corrosion, increasing the durability and lifespan of solar installations.

• Passivation Layers in c-Si Cells – Zinc compounds are sometimes used in surface passivation layers, reducing electron recombination and improving overall cell efficiency.

Batteries

Solar batteries

Solar batteries are essential for storing energy generated by photovoltaic (PV) systems, enabling a reliable and continuous power supply, even when sunlight is unavailable. These batteries enhance grid stability, energy independence, and renewable energy integration. Several critical minerals are used in solar battery technologies to improve performance, capacity, and longevity.

• Lead – A key component in lead-acid batteries, commonly used in off-grid and backup solar storage due to their low cost and reliability.

• Lithium – The primary material in lithium-ion batteries, offering high energy density, fast charging, and long cycle life, making them the dominant choice for modern solar storage.

• Iron – Used in iron-based battery chemistries, such as iron-flow batteries, providing durability and deep-cycle capabilities for large-scale energy storage.

• Phosphorus – A crucial element in lithium iron phosphate (LFP) batteries, enhancing thermal stability, safety, and longevity, making them ideal for solar energy applications.

Tesla Powerwall 2

The Tesla Powerwall 2 is a lithium-ion battery storage system designed to store energy from solar panels or the grid, providing backup power, energy independence, and improved grid resilience. It utilises advanced battery chemistry to enhance efficiency, lifespan, and performance.

Key critical minerals in the Tesla Powerwall 2 include:

• Lithium – The core element in lithium-ion cells, offering high energy density, fast charging, and long cycle life.

• Nickel – Enhances energy capacity and battery longevity, improving overall efficiency.

• Manganese – Contributes to stability and thermal control, ensuring safe and reliable operation.

• Cobalt – Increases battery lifespan and performance, preventing overheating and improving durability.

Grid infrastructure

Transmission and distribution

Efficient grid infrastructure is essential for transmitting and distributing solar-generated electricity from power plants to homes, businesses, and industries. A well-developed grid ensures minimal energy losses, system reliability, and efficient power flow. Several critical minerals are key to building and maintaining a resilient and efficient transmission network.

• Copper – The primary material in power cables and wiring, valued for its high electrical conductivity and durability, reducing energy losses over long distances.

• Aluminium – Used in overhead power lines due to its lightweight nature and cost-effectiveness, making it ideal for long-distance electricity transmission.

• Iron – Essential for transformers, pylons, and structural components, providing strength and stability in grid infrastructure.

Transformers

Transformers are essential components in electrical grids, regulating voltage levels to ensure the efficient transmission and distribution of electricity from solar power systems to end users. They play a critical role in minimising energy losses, improving grid stability, and enabling the integration of renewable energy sources.

• Copper – A key material in transformer windings, valued for its high electrical conductivity and thermal efficiency, ensuring effective energy transfer and minimal power loss.

Solar photovoltaic (PV) energy producers in North America

Solar photovoltaic (PV) energy producers in Europe

Solar photovoltaic (PV) energy producers in Central America and The Caribbean

Solar photovoltaic (PV) energy producers in South America

Solar photovoltaic (PV) energy producers in Africa

Solar photovoltaic (PV) energy producers in the Middle East

Solar photovoltaic (PV) energy producers in Asia

Solar photovoltaic (PV) energy producers in Southeast Asia

Solar photovoltaic (PV) energy producers in Australasia

Critical sectors using strategic minerals

Meet the Critical Minerals team

Trusted advice from a dedicated team of experts.