Solar photovoltaics, wind, and hydropower comprised over 80% of global electric capacity additions. The world's transition to 100% renewable energy seems unstoppable. In this talk I discuss the role of solar module technologies and their global supply situation. Decarbonization of the U.S. power sector by 2035 requires a threefold increase of annual solar installations versus today. The two incumbent module technologies are crystalline silicon and thin-film cadmium telluride, with 95% and 5% global market share, respectively. Substantial capacity growth of either technology is restricted by geopolitical factors, the scarcity and cost of critical raw materials, and the capex for new factories. I will review the state of the art as backdrop for a discussion of candidates for new, disruptive solar technologies. I will highlight the promise versus the risks of new technologies, such as hybrid-perovskites or tandem cells, as well as implications for high-volume manufacturing. I will conclude with describing the investments that are necessary today that may enable a future domestic, sustainable, affordable, and secure solar module production.