Solar panel installations per year

Solar panel installations and Tesla vehicle deliveries tracked each other between 2015 and 2022 with a correlation of 0.9736, leading several analysts to propose that Tesla is somehow made of solar panels, or that solar panels are secretly cars. Neither hypothesis has been confirmed. What has been confirmed is that wealthy coastal homeowners who want a solar roof also want a car that matches, and the data has captured this aesthetic preference with brutal precision.

Tesla deliveries grew from roughly 50,000 vehicles in 2015 to over 1.3 million by 2022, following an exponential curve as production capacity expanded and new models launched. Solar installations in the US grew over the same period from around 7 GW annually to over 20 GW, driven by falling panel costs, ITC tax credits, and utility-scale project expansion. Both are clean energy adoption curves riding the same policy environment — the IRA, state-level incentives, and corporate sustainability mandates — and the same technology cost deflation dynamics. Tesla buyers and solar adopters also significantly overlap demographically: upper-middle-income, environmentally motivated, early-adopter homeowners.

When two products serve the same values and the same customer, their growth curves become difficult to tell apart. This is a correlation with a genuine shared demographic signal, but it still tells you nothing about which one causes the other.