Global environmental constraints and induced technical change: towards radical innovation trajectories in the steel industry.

Summary This thesis investigates the steel industry and the ULCOS (Ultra Low CO2 Steelmaking) technological responses developed in the face of the "carbon" constraint (taxes, tradable permits) which adds to the industrial challenges and modifies the direction of technical change. Our analysis focuses more specifically on the conditions for the "greening" of innovations, the selection of a new technological sector and the inter-technological competition in an industry particularly prone to lock-in, taking into account the uncertainties of the specific selection environment (evolution of energy, carbon and raw material prices on production costs, steel demand, competition conditions...). The influence of the change in relative prices induced by the simulations of the constraints on the carbon and energy markets is studied from an applied partial equilibrium model. Using several concepts of industrial economics and investment under uncertainty to model the issues of decision, selection, adoption and diffusion of technologies, our thesis opens up new avenues of work by taking into account the expectations of actors and imperfect competition. The methodology developed in this empirical work is potentially applicable to other sectors (paper, cement, aluminum industries...) and provides answers to the theoretical questions identified by the multidisciplinary scientific agenda IHDP-Industrial transformation which solicits the complementary contributions of evolutionary and neoclassical theories of technical change