Developing Life Cycle Sustainability Assessment methodology by applying values-based sustainability weighting - Tested on biomass based and fossil transportation fuels

Highlights

• Introducing sustainability prioritization by different stakeholder profiles in LCSA.

• Considering a broad range of social impacts, including positive ones.

• Integration into an aggregated sustainability outcome.

• The sustainability ranking of fossil and biomass based fuels depends on world views.

• Sustainability assessments should consider potentially differing stakeholder values.

Abstract

The production and use of transportation fuels can lead to sustainability impacts. Assessing them simultaneously in a holistic way is a challenge. This paper examines methodology for assessing the sustainability performance of products in a more integrated way, including a broad range of social impacts. Life Cycle Sustainability Assessment (LCSA) methodology is applied for this assessment. LSCA often constitutes of the integration of results from social LCA (S-LCA), environmental life cycle assessment (E-LCA) and life cycle costing (LCC). In this study, an S-LCA from an earlier project is extended with a positive social aspect, as well as refined and detailed. E-LCA and LCC results are built from LCA database and literature. Multi Criteria Decision Analysis (MCDA) methodology is applied to integrate the results from the three different assessments into an LCSA. The weighting of key sustainability dimensions in the MCDA is performed in different ways, where the sustainability dimensions are prioritized differently priority based on the assumed values of different stakeholder profiles (Egalitarian, Hierarchist, and Individualist). The developed methodology is tested on selected biomass based and fossil transportation fuels - ethanol produced from Brazilian sugarcane and US corn/maize, and petrol produced from Russian and Nigerian crude oils, where it delineates differences in sustainability performance between products assessed. The outcome in terms of relative ranking of the transportation fuel chains based on sustainability performance differs when applying different decision-maker profiles. This result highlights and supports views that there is no one single answer regarding which of the alternatives that is most sustainable. Rather, it depends strongly upon the worldview and values held by the decision maker. A key conclusion is that sustainability assessments should pay more attention to potential differences in underlying values held by key stakeholders in relevant societal contexts. The LCSA methodology still faces challenges regarding results integration but MCDA in combination with stakeholder profiles appears to be a useful approach to build on further.

Introduction

The production and use of transportation fuels can lead to environmental as well as social impacts (Souza et al., 2015a). The European Union (EU) has implemented mandatory sustainability criteria for biofuels for transport in the Renewable Energy Directive (RED). These focus on greenhouse gas (GHG) emissions and biodiversity related demands (EuropeanParliament, 2009).

In general, existing transportation fuel-related certification efforts addressing sustainability have limitations. They primarily target biofuels and ignore incumbent fossil fuel chains (Harnesk et al., 2015). Further, the vast majority of sustainability assessment of transportation fuels focus on environmental impacts –and often primarily GHG emissions (Lazarevic and Martin, 2016, Rathore et al., 2016). To move towards sustainable development, as expressed in the newly adopted Sustainable Development Goals (UN, 2015), a more holistic approach to sustainability is needed. The main share of the SDGs is targeting social sustainability issues; poverty, hunger, health and equality, as well as access to important resources such as education, work, energy etc. Studies that include social issues linked to biofuels generally only address a limited number of issues, such as jobs generated (e.g. Miret et al., 2016, Santibañez-Aguilar et al., 2014, Yue et al., 2014) or security of supply (Buchholz et al., 2009).

The SDGs (UN, 2015) provide evidence of a growing consensus that sustainable development must be considered in a holistic manner, rather than considering environmental, economic and social impacts separated. In the realm of product assessment, where a life cycle approach is imperative, methods and praxis for Life Cycle Sustainability Assessment (LCSA) are under development to address this need for a more holistic sustainability approach. LCSA is a methodology to assess broad sustainability impacts, including environmental, social and economic aspects, from products and services. Klöpffer (2008) laid out the LCSA approach as a combination of the three life cycle approaches for environmental, social and costing perspectives with the scheme LCSA = LCA + LCC + S-LCA. Since then, there have been methodology development efforts, with important contributions from, among others, Finkbeiner et al. (2010) and the UNEP/SETAC Life Cycle Initiative report on LCSA (Finkbeiner et al., 2006, Valdivia et al., 2013). Also, the Life Cycle Sustainability Analysis (Guinee et al., 2010) has been proposed, an approach that broadens and deepens the assessment. Sala (Sala et al., 2013a, Sala et al., 2013b) discuss the scientific foundation for LCSA, and Guinée (2016) and Tarne et al. (2017) have presented recent overviews of the concept.

There is a need to broadening and deepening the LCSA methodology identified (Guinée, 2016). This work is focused on broadening the approach, to better include and integrate the three perspectives of sustainability. The outcomes of LCSAs have thus far largely been presented as three separate outcomes, presented side by side, without integration. Applications of LCSA in many cases lack a final integration step for the different sustainability perspectives. This omission requires users to make an integrated consideration of the overall sustainability impact themselves, without any methodological support. Yet, the importance of addressing the potential trade-offs between the different sustainability dimensions with transparency has been emphasized, and the challenge in doing so highlighted (Finkbeiner et al., 2010). One research need, identified for example in Tarne et al. (2017), is thus the development of methodology to aggregate the results into one combined result that can account for all three sustainability perspectives. Then, this integration of the three perspectives raises the question of prioritization among them. Who makes this prioritization and based on what? The importance of acknowledging value judgments in prioritization is for example identified in Bachmann (2013). Where such integration is done in literature, it is often done in a mathematical way, or in a non-transparent way by experts, not disclosing their underlying values (e.g. Çelikbilek and Tüysüz, 2016, Onat et al., 2016a, Onat et al., 2016b, Ren et al., 2015). However, in Volkart et al. (2016), such a mathematical approach is complemented by a prioritization based on two stakeholder profiles, with priorities assumed by the authors.

Moreover, the social dimension is to a lesser extent considered in sustainability assessments (Rafiaani et al., 2017) and when included, in many cases only a limited number, of social aspects are considered. Social impacts assessed for transportation fuels are usually limited to issues such as food security, poverty and/or job creation (e.g. Miret et al., 2016, Mirzabaev et al., 2015, Yue et al., 2014). Exceptions are for example studies by Corona et al., 2017, Ren et al., 2015, Valente et al., 2017, where a substantial number of social indicators were considered.

The purpose of this paper is to examine methodology to assess the sustainability performance of products in an integrated way employing different stakeholder perspectives for prioritization. Further, the methodology encompasses taking a broader spectrum of social aspects into account, as well as considering both positive and negative social impacts, as called for in Sala et al. (2013b) and Bachmann (2013). An integrated LCSA approach conducted by Multi Criteria Decision Analysis (MCDA) is designed, and tested on selected biomass based and fossil transportation fuel chains. The testing is performed on ethanol derived from Brazilian sugarcane, ethanol from US corn/maize (both utilizing first generation technologies), and petrol/gasoline derived from Russian and Nigerian crude oils. These fuel chains were selected as they in the preceding study presenting initial S-LCA results (Ekener-Petersen et al., 2014) they were judged to have relatively high potential risks of negative social impacts. Further, they have relatively high data availability and are thus convenient to use in a test case.

The prime focus of this work is on methodology development for LCSA, and the outcomes of the assessment on transportation fuels should be seen as indicative, mainly due to the limited detailing and robustness in the data sources utilized, for example the use of secondary data in the case of environmental impacts.

Even though there are studies including LCA of fossil and different biomass based transportation fuels (e.g. Cavalett et al., 2013, Daylan and Ciliz, 2016, Guo et al., 2015, Hong, 2012, Morales et al., 2017, Nanaki and Koroneos, 2012, Yang et al., 2012), to our knowledge, stakeholder profiles have not been employed in LCSA and MCDA before in such an assessment.