Exclusive: Start-Up Offers Copper Paste As A Cost-Effective Alternative To Silver In Solar Panels

Within the solar power industry, silver is a crucial material within the manufacturing of photovoltaic panels. Silver is turned into a paste that is loaded into the silicon wafers within the panel. When sunlight shines on the panels, the silicon releases the electrons and the silicon carries the sun-borne electricity through a current that either powers a building or goes to a solar battery for storage.

As the demand for solar power installations has grown over the past several years, so has the demand for the silver used in the panels. Silver’s use in photovoltaics increased 13% to 113.7 million ounces from 2020 to 2021, according to data from the Silver Institute, which also observed that global silver demand in 2021 reached 32,627 tons, surpassing the pre-pandemic environment to reach the highest level since 2015. Industrial fabrication grew by 9.3% to 15,807 tons last year.

“This mainly reflected the effects of a resumption of industrial operations and the re-opening of businesses as economies began to recover from COVID,” the Silver Institute said in its data report. “Other supportive factors included the demands of the home working economy, a boom for consumer electronics, 5G infrastructure investment, inventory build along the supply pipeline and rising end-use in the green economy, chiefly in photovoltaics.”

But simultaneous with rising demand are rising prices. The Silver Institute also reported a 22% year-over-year increase in silver prices during 2021, reaching a nine-year high of $25.14 per troy ounce. As silver prices and demand grows, the price of photovoltaic panels will also be impacted.

A Different Solution: One solution to address rising silver prices is to swap it out in favor of copper, a significantly less expensive metal that is widely used in power transmission and generation. While copper prices have been rising – $4.24 per pound in 2021, up 50% from 2020 roughly 6% higher than the 2011 record of $4.01 per pound – it is still considerably less expensive than silver.

And that’s where Bert Thin Films comes in. Co-founded in 2015 by Dr. Thad Druffel, an engineering professor at Kentucky’s University of Louisville, and post-doctoral researcher Ruvini Dharmadasa, the mission behind Bert Thin Films is to promote copper paste dubbed “CuBert” as a solar panel material. The company had its roots in the university’s Conn Center for Renewable Energy Research and is now an independent privately-owned entity.

According to the company, the CuBert production is identical to the process used today with silver – the metal is printed and fired in the same manner as silver paste, with the same screen-printing equipment and belt furnaces currently used by solar panel manufacturers. Since the process is direct plug-and-play replacement that doesn’t require new technologies or machineries, the cost efficiencies are immediately realized.

“The idea of using copper as a replacement for silver has been an industry target for several years,” Druffel told Benzinga. “There are known issues with copper degrading the efficiency of solar cells over time, and previous attempts to use copper as a conductor on solar cells failed. My co-founder and I discussed countermeasures that could solve the copper induced degradation problem several years back and we came up with a concept that is a commercial alternative for silver.”

Druffel pointed out that copper is “nearly 1% of the cost of silver and is considerably more abundant than silver.” But costing less money doesn’t mean copper is less efficient.

“Copper has nearly the same conductivity to silver, so will produce the same performance,” Druffel added.

Thad Druffel

Growing A Start-Up: Bert Thin Films began in earnest in January 2015 with a $225,000 grant from the National Science Foundation designed to enable the manufacturing and commercializing of the copper paste creation process. The Kentucky state government followed up three months later with a $100,000 grant. The company received a combined $1.5 million in state and National Science Foundation grants in 2019 to further finance its work, while the U.S. Department of Energy Solar Energy Technologies Office allocated a $1 million grant in August 2021.

The investor community has also taken notice – earlier this year, the company secured $1 million in angel investments. Druffel stated he was not planning to point Bert Thin Films into becoming publicly traded at this time, stating that the company’s “current funding in combination with increasing support from industry partners is sufficient.”

At the moment, Bert Thin Film’s output is still in the testing phase, with Druffel reporting an enthusiastic early response from solar panel manufacturers evaluating the product.

“We are currently producing CuBert paste at our facility in Louisville that is being used for testing on solar cells from world leading manufacturers,” Druffel said. “We plan to continue production in Louisville for the foreseeable future.”

And while Druffle acknowledged that his company’s copper paste could be adapted to other situations, he is strictly focused on his current mission.

“Yes, there are other opportunities, but as of right now solar is the single biggest opportunity,” he said.

Photos: Top photo courtesy of Bert Thin Films, photo of Thad Druffel courtesy of the University of Louisville’s Conn Center for Renewable Energy Research.