Ireland has some very bold targets, as part of a substantial overall greenhouse gas emissions reduction ambition. It is unclear however to what extent these targets are consistent with the pace at which new technologies can enter the market and become widely adopted. This paper grapples with this by combining well-respected and empirically validated estimates of technology diffusion together with energy models. Its purpose is to illuminate some of Ireland’s challenges associated with meeting these targets. The results show Ireland’s electric vehicle and residential retrofitting goals would require rates of technology diffusion that are well beyond the historical rates internationally of even the most successful transformations to date. This result calls Ireland’s ambitions into question. Drawing on the theory of technology diffusion, the paper also provides insights into additional complementary policies that Ireland might consider in order to accelerate diffusion of key technologies. The paper demonstrates the means and the value of drawing on historical precedents to help determine the feasibility of future transition scenarios. It also points to how industry-standard diffusion theory can help to identify policy solutions to accelerate the energy transition.