Tuck professor finds that 14 years of tariffs on solar panels have hurt domestic solar manufacturing

In October 2025, Tuck School of Business professor Bryan Bollinger ’03, Th ’03 co-authored a National Bureau of Economic Research study about the impacts of American solar panel tariffs on domestic solar energy development with Cornell professor Todd Gerarden, Yale professor Kenneth Gillingham ’02 and Duke professor Daniel Xu. The study found that tariffs on solar panels made in China led to a decrease in domestic solar manufacturing and installment. 

As of November 2025, tariffs were at 47.5% on all Chinese exports. Earlier in 2025, President Donald Trump imposed sweeping tariffs on all Chinese exports, and retaliatory tariffs reached over 130% in April 2025.

Tariffs on Chinese-made solar panels have risen in the last decade-and-a-half. The federal government first imposed tariffs on solar panels made by Chinese manufacturers in November 2012 and increased them in December 2014 under the Obama administration. The Trump administration imposed additional tariffs in 2018 and 2019, which were further extended under the Biden administration. In 2024, solar panel tariffs were set at 50%, according to the Department of Energy.

The Dartmouth sat down with Bollinger to discuss his background, his research on tariffs and the future outlook of solar energy development in the United States.

Tell us about your background in renewable energy development and policy research.

BB: My interest dates back to my time as a student at the Thayer School of Engineering. I considered going back to work on renewable energy, but I ended up studying marketing at Stanford University, focusing on applied economics. One day, I met for coffee with a Dartmouth friend, Kenneth Gillingham ’02, at Stanford, and we realized we had a shared interest in solar and how it could move us away from fossil fuels and create household energy independence. We began our first couple of projects looking at the diffusion of solar technology.

What was the rationale behind this research project? 

BB: Since some of the cost of tariffs gets passed down to consumers, our goal was to estimate how increasing prices for residential solar adopters — so, households — and commercial solar systems impacted consumers. On one hand, American installers would be worse off as they performed fewer installations and thereby got fewer profits, but on the plus side, you would have a potential increase in domestic solar panel manufacturing. One of our tasks was to weigh these trade-offs and see to what extent those tariffs helped American manufacturers versus hurt installers and consumers. We also accounted for revenue impacts for the U.S. government, which saw a moderate increase.

What were the overall impacts of tariffs on imported solar panels?

BB: The net reduction in solar installations in the U.S. and losses for installers outweighed the gain in American manufacturing jobs. The gain in domestic production was fairly small, and in terms of energy independence, they don’t really materialize in the short term. Although we saw an increase in domestic manufacturing of solar panels, all of the wafers  — which are then assembled into solar cells, and then panels — were essentially still being imported from China. Also, most of the increased installations and manufacturing capability in the U.S. following tariffs are still from internationally-owned firms, not domestic manufacturers. 

What alternative policies did your research find to be more effective in sustaining solar energy development growth?

BB: We found that a manufacturing subsidy for domestic manufacturers would be more beneficial than solar tariffs. They would obviously cost the government money, but after quantifying the different effects, we found that the total gain in surplus for consumers, installers and manufacturers would be higher than the additional cost to the government for those manufacturing subsidies. If we really want to use tariffs as a policy tool to increase U.S manufacturing, we need to settle on a consistent tariff level, maybe in conjunction with a domestic manufacturing subsidy.

Under the current on-and-off-again regime, I think it’s hard for U.S. manufacturers to make optimal decisions. As a U.S. manufacturer, if I think tariffs might only be on for a brief period of time, I have little incentive to invest a lot of upfront money for new manufacturing capabilities. If tariffs are turned off, my costs now are still too high relative to prices on the international market. 

What are some challenges in researching solar industry development when tariffs are ever-changing?

BB: From a research perspective, changing policy landscapes provides variation, which allows us to learn more about how agents respond to changes, but one of the challenges is that we don’t get to see the real long-term effects. For this project, we avoided making long-term predictions and extrapolating much beyond the data.

We looked at the range of data and estimated what would have happened under a counterfactual. With tariffs, we can estimate consumers’ and firms’ responses to those tariffs. Alternatively, we could turn off tariffs and see, for instance, how it would affect prices, demand and what firms would do if they were optimally sourcing their solar panels from different production locations.

What recommendations do you have for households that are currently considering switching to solar?

BB: One of the challenges is being able to forecast what future costs will look like. You’re making a long-term investment, so it can be challenging to know whether or not it makes sense to wait. Consumers need to get quotes from multiple installers. It can become difficult to compare prices when one installer advises you to install many more panels than another installer, but many online tools out there make the decision easier by allowing you to compare financial benefits. 

This interview has been edited for clarity and length.