Lessons from the use of a long-term energy model for consequential life cycle assessment: The BTL case

Abstract

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.

Integrating Energy System Models in Life Cycle Management

“…Thus, similar descriptions of the energy supply chain-from resource extraction to final use-can be found in both models. Linking ESM and LCI may seem straightforward, as both models share a similar structure, but these models are conceived to be used independently, and overlapping features can easily result in problems such as double counting [5,6] or incomplete inventories. Faced with redundant information, the modellers need to choose which information prevails.…”

“…The use of energy system optimisation models (ESOM) together with life cycle thinking has the potential to underpin comprehensive understanding of the energy supply chain and its influence on sustainable production. There is a small but increasing number of studies combining life cycle assessment (LCA) and ESOM [3][4][5][6][7][8][9][10][11][12], ESOM best practices start to include LCM practices, such as goal and scope definition or the use of data quality indicators as a way to quantify epistemic uncertainty (i.e. the uncertainty associated with data quality) [13].…”

Exploring Challenges and Opportunities of Life Cycle Management in the Electricity Sector

“…CLCA often follows the step-wise procedure presented by Ekvall and Weidema ( 2004 ) and updated in Weidema et al ( 2009 ) to identify marginal technologies but its application to the electricity sector is not yet satisfactory (Treyer and Bauer 2014 ). Marginal changes in the electricity sector are likely to affect a range of technologies (Pehnt et al 2008 ;Mathiesen et al 2009 ) and it is not straightforward task to consistently identify them with a heuristic approach (Zamagni et al 2012 ;Earles and Halog 2011 ;Menten et al 2015 ). Energy system models such as TIMES or LEAP can help to overcome such diffi culties.…”

“…The effect of public policies, such as taxes or subsidies can be included in the analysis with the help of life cycle costing. The scenarios can be, however, highly sensitive to uncertainties (Menten et al 2015 ), and a thoughtful scenario analysis and a clear account of the limitations of studies is therefore needed. The integration of economic models increases substantially the number of variables, especially if general equilibrium models are used.…”

On the Assessment of the CO2 Mitigation Potential of Woody Biomass

“…Life Cycle Assessment (LCA) is widely used in literature to asses fossil CO2 abatement potential of bioenergy when substituting fossil fuels (McKechnie et al, 2011;Steubing et al, 2012;Gerber et al, 2013;Menten et al, 2013Menten et al, , 2015Martin et al, 2015). There are two approaches to calculate the potential of biomass to abate fossil CO2 through LCA: attributional and consequential.…”