title: Integrated evaluation of cost, emissions, and resource potential for algal biofuels at the national scale.
abstract: Costs, emissions, and resource availability were modeled for the production of 5 billion gallons yr(-1) (5 BGY) of renewable diesel in the United States from Chlorella biomass by hydrothermal liquefaction (HTL). The HTL model utilized data from a continuous 1-L reactor including catalytic hydrothermal gasification of the aqueous phase, and catalytic hydrotreatment of the HTL oil. A biophysical algae growth model coupled with weather and pond simulations predicted biomass productivity from experimental growth parameters, allowing site-by-site and temporal prediction of biomass production. The 5 BGY scale required geographically and climatically distributed sites. Even though screening down to 5 BGY significantly reduced spatial and temporal variability, site-to-site, season-to-season, and interannual variations in productivity affected economic and environmental performance. Performance metrics based on annual average or peak productivity were inadequate; temporally and spatially explicit computations allowed more rigorous analysis of these dynamic systems. For example, 3-season operation with a winter shutdown was favored to avoid high greenhouse gas emissions, but economic performance was harmed by underutilized equipment during slow-growth periods. Thus, analysis of algal biofuel pathways must combine spatiotemporal resource assessment, economic analysis, and environmental analysis integrated over many sites when assessing national scale performance.
authors.affiliation: Center for Transportation Research, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Davis
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Fishman
authors.forename: Edward D
authors.initials: ED
authors.lastname: Frank
authors.forename: Michael C
authors.initials: MC
authors.lastname: Johnson
authors.forename: Susanne B
authors.initials: SB
authors.lastname: Jones
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Kinchin
authors.forename: Richard L
authors.initials: RL
authors.lastname: Skaggs
authors.forename: Erik R
authors.initials: ER
authors.lastname: Venteris
authors.forename: Mark S
authors.initials: MS
authors.lastname: Wigmosta
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000191:economics*; D056804:Biofuels / Q000032:analysis* / Q000191:economics*; D018533:Biomass; D002708:Chlorella / Q000378:metabolism*; D003365:Costs and Cost Analysis; D005742:Gasoline / Q000032:analysis / Q000191:economics; D005843:Geography; D017752:Greenhouse Effect; D014481:United States
chemical_list: D000393:Air Pollutants; D056804:Biofuels; D005742:Gasoline