This paper discusses the three stages of energy technology innovation — research, engineering, and commercialization — and recommends tools and practices that should be implemented at each stage to best stimulate energy technology innovation. Recommendations include “stage gating” research to shut down failures early (for research), granting industry access to costly government resources and facilities (for engineering), and ensuring long-term, large market signals to provide investment certainty and influence large-scale adoption (for commercialization).