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One of the issues with large‐scale perennial energy crop production is increasing land use competition between 'food and feed' and 'fuel'. A commonly suggested solution is to limit energy crop plantation to marginal lands. However, the concept and the methods used to assess marginal lands remain vague and inconsistent across bioenergy‐related studies. We propose a sustainability‐based framework to review and classify studies for marginal lands used for bioenergy crops. This framework innovatively puts the marginal land in a sustainability‐based framework, showing the interaction of biophysical, socioeconomic, qualitative, and quantitative assessments. We found that current studies lack integration of biophysical and socioeconomic considerations in the marginal land analysis. They also lack qualitative approaches to assess marginal land. We suggest that future work should emphasize integrating biophysical, socioeconomic, quantitative, and qualitative analysis for sustainable marginal land identification and use. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Social and economic indicators can be used to support design of sustainable energy systems. Indicators representing categories of social well-being, energy security, external trade, profitability, resource conservation, and social acceptability have not yet been measured in published sustainability assessments for commercial algal biofuel facilities. We review socioeconomic indicators that have been modeled at the commercial scale or measured at the pilot or laboratory scale, as well as factors that affect them, and discuss additional indicators that should be measured during commercialization to form a more complete picture of socioeconomic sustainability of algal biofuels. Indicators estimated in the scientific literature include the profitability indicators, return on investment (ROI) and net present value (NPV), and the resource conservation indicator, fossil energy return on investment (EROI). These modeled indicators have clear sustainability targets and have been used to design sustainable algal biofuel systems. Factors affecting ROI, NPV, and EROI include infrastructure, process choices, and financial assumptions. The food security indicator, percent change in food price volatility, is probably zero where agricultural lands are not used for production of algae-based biofuels; however, food-related coproducts from algae could enhance food security. The energy security indicators energy security premium and fuel price volatility and external trade indicators terms of trade and trade volume cannot be projected into the future with accuracy prior to commercialization. Together with environmental sustainability indicators, the use of a suite of socioeconomic sustainability indicators should contribute to progress toward sustainability of algal biofuels. [ABSTRACT FROM AUTHOR]