The future of solar energy: A personal assessment

To reduce global carbon dioxide emissions substantially by mid-century, electricity generation from solar energy will likely have to be increased dramatically. While the intermittency of the solar resource and the use of rare elements in some current solar technologies are concerns, the most important barrier to a massive scale-up is the current high cost of solar electricity, which will make a dramatic increase in solar deployment politically difficult in many countries. Ambitious publicly-funded research and development efforts aimed at fundamental advances constitute the most plausible approach to substantial cost reductions. Current deployment support programs are generally inefficient, particularly those that favor residential-scale systems, and are less likely to reduce costs substantially.