Manufacturing all silicon solar panels to be deployed in the United States domestically would reduce greenhouse gas emissions by 23% and energy use by 4% compared to outsourced manufacturing, according to a new analysis. The findings suggest that “reshoring” solar panel production could help the country decarbonize faster.
About 3.4% of the U.S. electricity supply currently comes from solar energy, but that could increase to as much as 50% in 2050. That massive ramp-up in solar power generation would require a surge in solar panel production and installation.
Silicon solar panels installed in the U.S. nowadays are mostly made in Asia. But this globalized supply chain is fragile, as demonstrated by the pandemic-related freight disruptions and other geopolitical crises – putting solar projects and ambitious green energy goals at risk.
These concerns have the U.S. already moving away from imported solar panels, a trend that is likely to continue especially in light of the “Buy American” provisions to promote domestic clean energy industry in the 2022 Inflation Reduction Act.
Past investigations of solar panel reshoring have mostly focused on these supply chain issues, but the climate implications of the reshoring strategy weren’t clear.
“We anticipated that reshoring solar panel manufacturing to the U.S. would improve environmental and energy performance, but it was surprising to discover just how well this approach aligns with our energy policies and climate action efforts,” says Fengqi You, an energy systems engineer and sustainability researcher at Cornell University in Ithaca, New York.
You and Haoyue Liang, a graduate student in systems engineering at Cornell, conducted a “cradle-to-site” life-cycle analysis of silicon solar panel manufacturing, tracing the process from the mining of silica sand through the production of panels in various countries to transportation and installation at their final destination.
Energy use and greenhouse gas emissions associated with solar panel use, maintenance, and eventual disposal are minimal – so the manufacturing phase really matters.
Manufacturing solar panels takes a lot of electricity. Different mixes of power sources in different countries result in varying greenhouse gas impacts of solar panel manufacturing, the researchers report in Nature Communications. For example, in 2020 38% of US solar panels manufactured in Malaysia, which is still heavily dependent on coal electricity.
As the U.S. power grid decarbonizes and gets more efficient, domestic solar panel manufacturing looks better and better compared to the status quo. Reshoring solar panel manufacturing by 2035 would result in 30% lower greenhouse gas emissions and 13% lower energy use compared to relying on the same globalized sources as in 2020. In 2050, the benefits of reshoring solar panel manufacturing amount to 33% lower greenhouse gas emissions and 17% lower energy use.
In other words, the researchers argue, reshoring solar panel production and decarbonization of the grid go hand in hand – each helps make the other possible and each increases the benefits of the other. “Reshoring solar panel manufacturing in the U.S. supports the solar energy industry’s decarbonization efforts,” You says.
Although the current study focuses on the U.S., its conclusions are likely more broadly applicable. “When solar panel production is shifted to locations with cleaner energy sources, it results in more sustainable manufacturing and improved global climate outcomes,” You says. In that sense, reshoring U.S. solar panel manufacturing is a climate win for the world, not just for the U.S.
The benefits of reshoring solar panel manufacturing to other countries would “likely vary on a case-by-case basis due to differences in energy structures, industrial economies, supply chain systems, and other socio-economic and environmental factors,” says You. “For instance, manufacturing solar panels in Singapore could be more climate-friendly than in the U.S., but the limited manufacturing capacity in Singapore makes it unrealistic to shift large volumes of production there.”
“In general, if a country previously depended on solar energy products manufactured in another country that primarily relied on non-renewable energy sources, reshoring production to the consumer country would likely yield benefits both for the nation and global climate action,” You explains.
Source: Liang H. and F. You. Reshoring silicon photovoltaics manufacturing contributes to decarbonization and climate change mitigation. Nature Communications 2023
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