Abstract
Socio-economic sustainability indicators that have been proposed previously for terrestrial bioenergy were evaluated for applicability to algal biofuels. Indicators developed for terrestrial bioenergy were found to be appropriate and sufficient for algae biofuels, meeting the selection criteria of practicality, wide applicability, predictability in response to management, anticipation of future changes, adaptability to multiple scales where possible, ability to integrate multiple dimensions, and non-redundancy. The 16 indicators fall into the categories of social well-being, energy security, external trade, profitability, resource conservation, and social acceptability. None of the indicators have yet been measured in published sustainability assessments for commercial facilities. Indicators estimated for various scenarios in the scientific literature include the profitability indicators return on investment and net present value, and the resource conservation indicator, fossil energy return on investment. The food security indicator, percent change in food price volatility, is easy to estimate at zero if agricultural lands are not used. Some indicators, such as the energy security indicators energy security premium and fuel price volatility and the external trade indicators terms of trade and trade volume cannot be projected into the future with accuracy, so they will not be measured prior to significant commercialization of algal biofuels. The list of proposed sustainability indicators may be adjusted to particular purposes and contexts. Together with environmental sustainability indicators, these socioeconomic sustainability indicators should contribute to sustainability assessments for algal biofuels.
