Coordination of sectoral climate policies and life cycle emissions[Coordination des politiques climatiques sectorielles et des émissions de cycle de vie]

Drastically reducing greenhouse gas emissions involves numerous specific actions in each sector of the economy. The costs and abatement potential of these measures are interdependent because of sectoral linkages. For instance, the carbon footprint of electric vehicles depends on the electricity mix. This issue has received large attention in the literature on Life Cycle Assessments (LCA). This paper analyzes how life cycle considerations should be integrated into policy design. We model a partial equilibrium with two vertically connected sectors, an upstream (e.g. electricity) and a downstream (e.g. transportation) one. In each sector, a dirty and a clean technology are available. The clean downstream technology consumes the upstream good and may thus shift emissions to the upstream sector. Our main contribution is to detail how optimal subsidies on clean technologies should incorporate life cycle emissions when carbon pricing is limited. The optimal downstream subsidy should be corrected for all external costs generated in the upstream sector, not only unpriced pollution but also the fiscal externality due to the subsidy to the clean upstream technology. We also analyze the joint optimization of upstream and downstream policies. The upstream subsidy should not incorporate features of the downstream sector, whereas the downstream optimal subsidy depends upon the upstream sector characteristics. All results are illustrated using a calibrated example of the electrification of passenger cars.