The $21 billion capex bill: analyzing the cost of the U.S. 100 GW module production milestone

The U.S. solar panel manufacturing industry has now produced 100 gigawatts of solar panels in total, a milestone reached in mid-2026. New research looks at what it cost to get there: about $21 billion in factory spending over more than 50 years, dating back to the early 1970s.

The money was spent unevenly. First Solar, the country's main maker of thin-film panels (a type of solar panel that doesn't use standard silicon cells), accounts for roughly a quarter of all that spending on its own, and it's the only U.S. thin-film manufacturer that has lasted. A five-year boom in other thin-film factories around 2007-2012, with companies like Solyndra and Abound Solar, soaked up about $3.4 billion but left almost nothing behind — those factories contributed only about 1% of the total panels ever produced. Standard silicon-panel manufacturing struggled for decades too, with repeated false starts, until the 2022 Inflation Reduction Act and its manufacturing tax credit (called Section 45X) triggered a real surge: since 2023, silicon-panel factory spending has made up nearly 40% of all U.S. solar manufacturing investment ever, in just three and a half years.

None of this changes what panels cost or what rebates are available today, but it matters for anyone thinking long-term about American-made solar equipment. The open question is whether this new wave of factories, backed by tax credits and newer trade rules, will actually keep running for decades the way First Solar has, or fade like the thin-film boom did.