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To study the potential effects of increased biofuel use, we evaluated six representative analyses of fuel ethanol. Studies that reported negative net energy incorrectly ignored coproducts and used some obsolete data. All studies indicated that current corn ethanol technologies are much less petroleum-intensive than gasoline but have greenhouse gas emissions… (More)
The life cycle greenhouse gas (GHG) emissions induced by increased biofuel consumption are highly uncertain: individual estimates vary from each other and each has a wide intrinsic error band. Using a reduced-form model, we estimated that the bounding range for emissions from indirect land-use change (ILUC) from US corn ethanol expansion was 10 to 340 g… (More)
1 T here is a divergence of views on future bioenergy deployment that is based in disparate epistemic communities. Integrated assessment models (IAMs) project rising deployment of bio-mass and biofuels in climate change-mitigation scenarios 1,2. In contrast , life-cycle assessments (LCAs) and partial equilibrium models of land-use change emphasize high… (More)
Biomass can help reduce greenhouse gas (GHG) emissions by displacing petroleum in the transportation sector, by displacing fossil-based electricity, and by sequestering atmospheric carbon. Which use mitigates the most emissions depends on market and regulatory contexts outside the scope of attributional life cycle assessments. We show that bioelectricity's… (More)
1420 27 MARCH 2015 • VOL 347 ISSUE 6229 sciencemag.org SCIENCE D ebates about biofuels tend to focus separately on estimates of adverse effects on food security, poverty, and greenhouse gas (GHG) emissions driven by land-use change (LUC) ( 1– 4). These estimates often rely on global agriculture and land-use models. Because models differ substantially in… (More)
Few of the numerous published studies of the emissions from biofuels-induced "indirect" land use change (ILUC) attempt to propagate and quantify uncertainty, and those that have done so have restricted their analysis to a portion of the modeling systems used. In this study, we pair a global, computable general equilibrium model with a model of greenhouse… (More)
Few integrated analysis models examine significant U.S. transportation greenhouse gas emission reductions within an integrated energy system. Our analysis, using a bottom-up MARKet ALocation (MARKAL) model, found that stringent system-wide CO2 reduction targets will be required to achieve significant CO2 reductions from the transportation sector. Mitigating… (More)
1. Current Legislative Context Among current legislative approaches to the issue of biofuels and sustainability, see: United States: Section 202 of the 2007 Energy Independence and Security Act (EISA) requires 36 billion gallons of renewable fuel by 2022. Of that total, 15 billion gallons may be 'conventional', or corn-based ethanol. The renewable fuel… (More)
The following section was expanded to include a new analysis • Sensitivity Analysis (p. 18) In addition, the following corrections were made: • Farm Machinery as reported in (1) was added to Table S2 (p. 21) • Added note on Farm labor transport energy on page 7. • Corrected Figure 2 from the paper (Figure S3, here) as a result of updated lime values.
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