TABLE 1-1 Examples of Sustainability Criteria Used to Evaluate Plant-Based Biofuels.

Sustainability Criteria



•  Cost of production

Cost competitiveness with respect to other fuel alternatives.

•  Economic development

Effects on the standard of living and economic health.

•  Fiscal effects

Effects on fiscal balances.

•  Employment

Employment creation.

Resource Use and Environmental

•  Energy balance

Energy output in fuel per unit of energy input to make the fuel over its life cycle.

•  Resource use including land and water

Land and water requirements to produce one unit of fuel.

•  Pollutant emissions including GHG and criteria pollutants

Emissions (for example, CO2 and sulfur oxides) over the life cycle of one unit of fuel.

•  Biodiversity

Effects on ecological species and communities (for example, habitat destruction or enhancement).


•  Competition for resources being used for other human activities

Effects of resource use (for example, water and nutrients) for biofuel production on other activities (for example, farming food crops and animals).

•  Cultural acceptability

Acceptability of the effects of biofuel production.

•  Visual impacts

Perception of landscape aesthetics.

•  Health effects

Effects of emissions (for example, air-quality emissions) on human health.

produced, but technological progress could enhance the productivity of algal feedstock and fuel yield. Economics

Cost of production is an important aspect of sustainable development that applies to all nonpetroleum-based alternative fuels including algal biofuels. Alternative fuels are not likely to penetrate the fuel markets if they are much more expensive for consumers than other fuel alternatives (NRC, 2008, 2011b). Although government policies and subsidies can facilitate and accelerate the market penetration of biofuels, the biofuels eventually would have to become economically viable without subsidy. Brazilian ethanol was heavily subsidized when Brazil’s National Alcohol Program was initiated, but the government subsidies gradually were phased out in the 1990s. Sugar-cane ethanol has been economically viable in Brazil since 2003 (Solomon, 2010).

As discussed in Box 1-1, the committee was not asked to analyze costs of algal biofuels. Published estimates for costs of algal oil and algal biofuels span a wide range of about $1-$25 per gallon (Williams and Laurens, 2010; Gallagher, 2011; and references cited therein). The wide range reflects a number of factors including when the estimate was made. The cost estimates reported in the literature were not in constant dollars and therefore are not directly comparable. Some cost estimates were for algal oil before upgrading to fuels. A wide range of technologies could be used in an algal biofuel production system resulting in varying costs. This range in estimated costs reflects the immaturity of algal biofuel production and the uncertainties associated with a developing industry (Williams and Laurens, 2010). It is still premature to analyze and draw any conclusions about the economic sustainability of algal biofuels, particularly when costs likely will decrease with ongoing

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