How Zero-Waste Thinking Helped Build Rio Tinto a Solar Array

Rio Tinto's 25-megawatt solar project at its Kennecott mine is an example of how mining operations can close the loop on energy production.

The solar plant, located at the firm's copper mine in Utah, is a milestone in the company’s mission to shrink its carbon footprint.

But what exactly makes this particular solar array remarkable? The answer can be found in tellurium.

Tellurium is a by-product in the copper refining process, but it is also commonly used when manufacturing solar panels, meaning that Rio Tinto is able to supply itself with the key components of renewable energy generation. 

By using tellurium, the facility is able to cut down on its waste, its reliance on grid electricity and its Scope 2 emissions, creating a win-win-win scenario.

Together with a 5MW installation completed in 2023, Kennecott now produces 30MW of renewable energy – enough to power more than 1,000 typical American homes each year and cut Scope 2 emissions by around 6%, equivalent to removing 4,400 cars from the road annually.

Mining meets renewables in a closed-loop model

The team at Rio Tinto has been enthusiastic about all the benefits this new power system will bring to its Kennecott operations.

Nate Foster, Managing Director of Rio Tinto Kennecott, says: "This new solar plant is more than a source of renewable power for our operations; it's a demonstration of circularity and supply chain resilience.

"By mining copper and tellurium, both classified as critical minerals in the US, here at Kennecott and using that tellurium in the panels powering our site, we're proving how domestic critical minerals support renewable energy manufacturing.

"This approach strengthens North America's supply chain for essential resources, supports national energy security, and reinforces our commitment to a low-carbon future."

By integrating mining and energy innovation in a single ecosystem, Kennecott shows that mining operations are able to abate emissions through clever thinking.

Now, Kennecott effectively stands as an energy production hub that can contribute directly to renewable generation.

Accelerating the energy transition

Copper and tellurium are both recognised by the US government as critical to achieving energy independence and accelerating the shift to renewables.

Kennecott is now one of just two sites in the nation producing tellurium – a metal essential to high-performance photovoltaic panels – and one of just two copper smelters still operating in the US.

Through its tellurium refining process, which began in 2022, Kennecott not only supports renewable energy supply chains but also strengthens North America’s position in the global clean-energy marketplace.

The tellurium produced there is processed by Canada-based 5N Plus Inc. into semiconductor materials for First Solar, which manufactures the same panels now generating power for Kennecott.

Gervais Jacques, CEO of 5N Plus, says: "Our partnership with Rio Tinto helps deliver industry-leading products that support the clean energy transition and advance national energy security.

"At a time when the security of critical minerals supply chains is under intense scrutiny, we're pleased to reinforce our position as a trusted partner to deliver the advanced materials this critical and growing sector depends on."

Rapid renewable deployment delivers results

The 25MW solar array, developed in partnership with Bechtel, progressed from initial construction in October 2024 to full operation just over a year later.

With more than 71,000 panels made from locally-sourced tellurium, the project provides a tangible example of energy circularity in action.

"Working closely with Rio Tinto, Bechtel is proud to have delivered this project two months ahead of schedule while supporting 200 local jobs, helping bring renewable energy to the mine," says Scott Austin, General Manager of Renewables & Clean Power at Bechtel.

"We look forward to future projects together."

Strengthening energy security through collaboration

From on-site solar generation to its role in supplying materials for clean-tech manufacturing, Rio Tinto’s work at Kennecott marks a significant contribution to regional energy resilience.

These innovations feed into a broader company strategy that includes decarbonising heavy mining fleets and advancing battery-powered truck trials alongside BHP, Caterpillar and WesTrac in Australia’s Pilbara.

Rio Tinto’s renewable energy expansion underlines how industrial operations can evolve from being energy-intensive consumers to active contributors in the clean energy economy – creating a model where mining fuels not only materials but also the sustainable power systems of the future.