Stimulating research and development (R&D) of innovative energy-efficient technologies for industry is an attractive option for reducing greenhouse gas emissions. Impulse technology, an innovative papermaking technology, is always included in studies assessing the long-term potential of industrial energy efficiency. Aim of this article is to analyse the R&D trajectory of impulse technology in order to explore how government can stimulate the development of industrial energy-efficient technology. The concept of 'momentum' is used to characterise the network of actors and to understand the effect of government R&D support in this particular case study. The network analysis convincingly shows that although marketed as an energy-efficient technology, other benefits were in fact driving forces. Researchers at various national pulp & paper research institutes were successful in attracting government R&D support by claiming an improved energy efficiency. The momentum of the technology network was modest between 1980 and 1990. Therefore, government R&D support accelerated the development of impulse technology in this period. However, when the perspectives of the technology deteriorated-momentum decreased-researchers at national research institutes continued to attract government R&D support successfully. But 25 years of R&D-and over 15 years government R&D support-have not yet resulted in a proven technology. The case study illustrates the risk of continuing R&D support too long without taking into account actors' drivers to invest ill R&D. Once momentum decreased, government should have been more circumspect in evaluating the (energy efficiency) promise of impulse technology. The major policy lesson is that government has to look beyond claimed energy efficiencies; government has to value (qualitative) information oil (changing) technology networks in deciding upon starting, continuing or pulling out financial R&D support to industrial energy-efficient technology. (C) 2003 Elsevier Science Ltd. All rights reserved.