The paper aims at explaining why large-scale energy-intensive industries-here the German iron and steel industry-had a period of slow uptake of major energy-efficient technologies from the mid 1990s to mid 2000s (Arens and Worrell, 2014) and why from the mid 2000s onwards these technologies are increasingly implemented again. We analyze the underlying factors and investment/innovation behavior of individual firms in the German iron and steel industry to better understand barriers and drivers for technological change. The paper gives insights on the decision-making process on energy efficiency in firms and helps to understand how policy affects decision-making. We use a mixed method approach. First, we analyze the diffusion of three energy-efficient technologies (EET) for primary steelmaking from their introduction until today (top-pressure recovery turbine (TRT), basic oxygen furnace gas recovery (BOFGR), and pulverized coal injection (PCI)). We derive the uptake of these technologies both at the national level and at the level of the individual firm. Second, we analyze the impact of drivers and barriers on the decision-making process of individual firms whether or not they want to implement these technologies. Economics and access to capital are the foremost barriers to the uptake of an EET. If the expected payback period exceeds a certain value or if the company lacks capital, investments in EET seem not to happen. But even if an EET is economically viable and the company has access to capital, investments in EET might not be realized. Policy-induced prices might have strengthened the recent diffusion of TRT. We found indications that in a limited number of cases, policy intervention was a driving factor. Technical risks and imperfect information are only marginal factors in our cases. Site-specific factors seem to be important, as site-specific factors shape the economics of the selected EET.