This lecture focuses on two questions: What is the history of US energy transitions? And to what extent does the current transition from fossil fuels to alternative energies (primarily solar and wind power) differ from these earlier transitions? The answer to the first question is largely based on Nye's "Consuming Power" (MIT Press, 1998) and the work of Thomas Hughes, particularly the concept of technological momentum; this includes discussion of the shifts from water power to steam to electricity and fossil fuels.