Technology costs and deployment rates, represented in experience curves, are typically seen as the main factors in the global clean energy transition from fossil fuels towards low-carbon energy sources. We argue that politics is the hidden dimension of technology experience curves, as it affects both costs and deployment. We draw from empirical analyses of diverse North American and European cases to describe patterns of political conflict surrounding clean energy adoption across a variety of technologies. Our analysis highlights that different political logics shape costs and deployment at different stages along the experience curve. The political institutions and conditions that nurture new technologies into economic winners are not always the same conditions that let incumbent technologies become economic losers. Thus, as the scale of technology adoption moves from niches towards systems, new political coalitions are necessary to push complementary system-wide technology. Since the cost curve is integrated globally, different countries can contribute to different steps in the transition as a function of their individual comparative political advantages.