Working in just one segment of the broader energy industry, it is easy to get caught up in the tasks at hand and lose sight of the bigger picture. What are our mutual sustainability goals? How do we track our progress? Are we on a sustainable path?
The IEA’s Net Zero Emissions Scenario defines a path for the global energy sector to achieve net-zero CO2 emissions by 2050 while also improving energy access and air quality. The latest “Clean Energy Progress” report notes that out of over 50 critical components of the energy system, only three are “on track” with the net-zero by 2050 trajectory. Solar energy made the cut (along with EVs and lighting). Last year, solar PV generation increased by 26%, reaching almost 1,300 TWh. This was the largest absolute generation growth of all renewable technologies in that year, surpassing wind for the first time ever. Installed capacity of solar is set to overtake coal by 2027, making it the largest share of any energy technology in the world.
Although this is great progress, IEA stresses that we still need further geographic diversification of the supply chain moving forward. Due to investment and government policies in the United States, India and European Union, IEA estimates global capacity will more than double in the next five years, yet the group expects China to maintain its 80-95% share in solar PV manufacturing capacity over that period. And there is more we can do to reduce the carbon footprint of our industry. Manufacturing costly silicon solar cells requiring a complex supply chain, and then shipping them around the world in products that are more difficult to recycle, is clearly not the most sustainable solution.
This is where we need to ask some hard questions for the U.S. market: Do we diversify here with more silicon, which will require the United States to duplicate what China already does so well? Or should we look further at thin-film PV?
Thin-film technologies that have been successfully commercialized to the gigawatt-scale in the United States and Japan have leveraged lower capital costs, a less volatile material supply chain, manufacturing innovation and superior cost-performance and sustainability metrics to stay competitive against Chinese silicon. The energy security advantages of decentralizing the global supply chain are clear, as evidenced by the U.S. government’s push to subsidize U.S. manufacturing, but as Bloomberg reports, “the lesson from the last decade is the U.S. has to be committed — and has to be as committed as China.”
First Solar is a shining example of the value that thin film can bring to help strengthen the U.S. domestic manufacturing base. In 2021, CIGS manufacturer Solar Frontier succumbed to foreign import pressures after a strong decade of gigawatt-scale production in Japan where it had amassed significant market share. First Solar, on the other hand, has not only survived in the United States but continues to expand. A recent WSJ article noted First Solar will likely secure a 60% share of the U.S. market for large-scale solar installations this year with the help of the IRA. And it is worth noting that thin film had made inroads in the U.S. market long before the IRA was announced. A quick look at Lawrence Berkely Lab’s utility-scale solar report shows that between 2007 and 2022, thin film accounted for over 30% of total installed PV capacity. And that was accomplished almost single-handedly by a U.S. company competing against a flood of imports year after year.
With this great success story as a precedent, what are we waiting for? With single junction perovskites already demonstrating efficiencies on par with silicon cell technologies, and thin-film perovskite tandems not too far behind silicon tandems, we certainly have options. As with any new technology, there is still work to do on manufacturability and stability, but as First Solar has shown, these are not insurmountable tasks. And thin film makes sense from a sustainability perspective. Life-cycle analysis research conducted by NREL, Columbia University and HZB all demonstrate thin film’s ability to significantly reduce the embodied energy and carbon footprint of solar below that of silicon. Significantly, one paper from Columbia demonstrated that single junction perovskite PV modules produced with roll-to-roll manufacturing could reach in only 12 years of life the same energy ROI as that of single‐crystalline‐silicon PV lasting 30 years.
On top of evidence showing that thin film is superior to silicon on multiple sustainability metrics — even with or without circularity, thin-film companies serving domestic markets have been proactive on recycling and toxicity. As early as 2005, First Solar established a forward-thinking global recycling program extending into markets, such as the United States, that didn’t require one. Both Avancis and Solar Frontier developed a less toxic CIGS thin-film solution that replaced cadmium with zinc. Perovskites are no exception: for example, the minute amount of lead required to make metal halide perovskite cells is just a fraction of that used in silicon PV module tabbing ribbon (1.5-3.6mg/W for perovskites vs. 32.4 mg/W for silicon). This amount is estimated to be well below EPA risk levels — even in the remote chance 100% of the lead were to leach out into the environment. And to put things in perspective, an NREL paper on perovskites shows that in just one year, the electricity generation from coal in the United States alone resulted in more lead emitted into the atmosphere than what would be required to produce over 2 TW of perovskite solar capacity. This equates to more PV power than has been deployed across all PV technologies to date globally.
To stay on target with our global sustainability targets, we need more government support of industry to deploy innovative and sustainable manufacturing solutions in more regions of the world as quickly as possible — and the use of less energy, less material and lower supply chain risk to get us there just makes sense. To borrow a tagline from the American Dairy Association: Got Thin Film?
The views and opinions expressed in this article are those of the author and do not necessarily reflect the views or positions of the author’s employer.