Policy implications of uncertainty in modeled life-cycle greenhouse gas emissions of biofuels

Mullins, KA; Griffin, WM; Matthews, HS

HERO ID

755532

Reference Type

Journal Article

Year

2011

Language

English

PMID

21121672

HERO ID 755532
In Press No
Year 2011
Title Policy implications of uncertainty in modeled life-cycle greenhouse gas emissions of biofuels
Authors Mullins, KA; Griffin, WM; Matthews, HS
Journal Environmental Science & Technology
Volume 45
Issue 1
Page Numbers 132-138
Abstract Biofuels have received legislative support recently in California's Low-Carbon Fuel Standard and the Federal Energy Independence and Security Act. Both present new fuel types, but neither provides methodological guidelines for dealing with the inherent uncertainty in evaluating their potential life-cycle greenhouse gas emissions. Emissions reductions are based on point estimates only. This work demonstrates the use of Monte Carlo simulation to estimate life-cycle emissions distributions from ethanol and butanol from corn or switchgrass. Life-cycle emissions distributions for each feedstock and fuel pairing modeled span an order of magnitude or more. Using a streamlined life-cycle assessment, corn ethanol emissions range from 50 to 250 g CO(2)e/MJ, for example, and each feedstock-fuel pathway studied shows some probability of greater emissions than a distribution for gasoline. Potential GHG emissions reductions from displacing fossil fuels with biofuels are difficult to forecast given this high degree of uncertainty in life-cycle emissions. This uncertainty is driven by the importance and uncertainty of indirect land use change emissions. Incorporating uncertainty in the decision making process can illuminate the risks of policy failure (e.g., increased emissions), and a calculated risk of failure due to uncertainty can be used to inform more appropriate reduction targets in future biofuel policies.
Doi 10.1021/es1024993
Pmid 21121672
Wosid WOS:000285679300021
Is Certified Translation No
Dupe Override No
Is Public Yes
Language Text English
Is Qa No