The main objective of this study is to develop a methodology adapted to the prospective environmental evaluation of actions in the energy sector. It describes how a bottom-up long-term energy model can be used in a life cycle assessment (LCA) framework. The proposed methodology is applied in a case study about the global warming impacts occurring as a consequence of the future production of synthetic diesel from biomass ("biomass to liquids"-BTL), a secondgeneration biofuel, in France. The results show a high sensitivity of the system-wide GHG balance to (i) the policy context and to (ii) the economic environment. Both influence the substitutions occurring within the system due to the production of BTL. Under the specific conditions of this study, the consequences of introducing BTL are not clear-cut. Therefore, we focus on the lessons from the detailed analysis of the results more than in the precise-looking projections, illustrating how this type of models can be used for strategic planning (industry and policy makers). TIMES-type models allow a detailed description of the numerous technologies affected by BTL production and how these vary under different policy scenarios. Moreover, some recommendations are presented, which should contribute for a proper systematization of consequential and prospective LCA methodologies. We provide argumentation on how to define a functional unit and system boundaries that are better linked with the goal of the study. Other crucial methodological issues are also discussed: how to treat temporal aspects in such environmental evaluation and how to increase the consistency of life cycle assessments.

This paper examines the development of cooperative strategies between countries exporting Liquefied Natural Gas (LNG) and members of the Gas Exporting Countries Forum (GECF). This economic study focuses specifically on an often-raised scenario: the emergence of a cooperative approach designed with the sole aim of logistic rationalization, and which would not have any effect on LNG prices. We first assess the annual gains that may result from this market-power-free cooperative approach using a simple static transportation model. The numerical results obtained suggest that, in the absence of a gain redistribution policy, this cooperative strategy will probably not be adopted because cooperation would not be a rational move for some exporters. The problem of gain sharing is then formulated using cooperative game theory concepts. Several gain-sharing methods have been studied, including the Shapley value and various nucleolus-inspired concepts. Our results suggest that the choice of a redistribution policy appears relatively restricted. Out of the methods studied, only one -per capita nucleolus -satisfies two key requirements: core belonging and monotonicity (in the aggregate). Lastly, we look at how cooperation may give rise to a coordination cost and try to determine the maximum amount of this cost. In view of the low level of this amount and the relative complexity of the sharing method implemented, we consider that the credibility of a logistic cooperation scenario exempt from market power should be reappraised.

The overlap in sources of greenhouse gas and local air pollutant emissions creates scope for policy measures to limit global warming and improve air quality simultaneously. In a first step, we derive estimates for the air pollution mortality-related component of the social cost of atmospheric release for 6 pollutants and 56 regions in the world. Combining these estimates with emission inventory data highlights that sector contributions to greenhouse gas emissions and air pollution health impacts differ widely across regions. Next, simulations of future emission pathways consistent with the 2°C and 1.5°C targets illustrate that strengthening climate policy ambition raises the total value of air quality co-benefits despite lower marginal co-benefits per tonne of greenhouse gas emissions abated. Finally, we use results from a multimodel ensemble to quantify and compare the value of health-related ambient air quality cobenefits of climate policy across sectors and regions. On the global level, overall air quality cobenefits range from $8 to $40 per tonne of greenhouse gases abated in 2030, with median across models and scenarios of $18/tCO 2 e. These results mask strong differentiation across regions and sectors, with median co-benefits from mitigation in the residential and service sectors in India exceeding $500/tCO 2 e. By taking a sector-and region-specific perspective, the results presented here reveal promising channels to improve human health outcomes and to ratchet up greenhouse gas reduction efforts to bridge the gap between countries' pledges and the global targets of the Paris Agreement.

No abstract