UVM Theses and Dissertations
Format:
Print
Author:
Campbell, Eleanor
Dept./Program:
Natural Resources
Year:
2009
Degree:
MS
Abstract:
When substituted for their petroleum counterparts, biofuels can theoretically lead to a reduction in greenhouse gas (GHG) emissions through the sequestration of carbon during the feedstock growth process as well as the avoidance of fossil fuel-related emissions. However, biofuel production requires energy and material inputs that vary according to feedstock type and production method. This means that some biofuels may be more successful than others in meeting the goal of reduced GHG emissions from fuel use. This study assesses the GHG emissions associated with small-scale sunflower and canola biofuel crops grown with organic versus conventional methods on a northern Vermont farm. In this study, a field-based GHG life cycle assessment (LCA) was completed for each of these crops, wherein all GHG sinks, sources and offsets from 'cradle-to-grave', or from when the biofuel is produced to when it is used completely, were quantified.
The results of this study demonstrate that canola and sunflower biofuel crops produced with organic and conventional methods can lead to net GHG reductions when the resulting fuel is used in place of petroleum-based diesel. When biofuel coproducts were valued, all treatments resulted in negative GHG balances, with organic sunflower treatments resulting in the largest reduction of GHG emissions associated with fuel use (average of-1420 lb C0₂e per acre with harvest yields,) while organic canola resulted in the smallest reduction of GHG emissions (average GHG balance of-2261b C0₂e per acre with harvest yields). Removing the GHG value of the coproducts associated with the biofuel production process assessed in this study changed the GHG balance of the four treatments; when coproducts were excluded, only organic sunflower retained a negative GHG balance ( -292lb C0₂e per acre with harvest yields), while all other treatments had a positive GHG balance (71, 239, and 425 lb C0₂e per acre, conventional sunflower, conventional canola, and organic canola, respectively).
This study demonstrated the importance ofunderstanding specific crop types and production methods when quantifying the net GHG benefits of crop-based biofuels. Seed loss at harvest and coproduct valuation emerged as important factors that need to be considered as farm-scale crop-based biofuel production develops in New England.
The results of this study demonstrate that canola and sunflower biofuel crops produced with organic and conventional methods can lead to net GHG reductions when the resulting fuel is used in place of petroleum-based diesel. When biofuel coproducts were valued, all treatments resulted in negative GHG balances, with organic sunflower treatments resulting in the largest reduction of GHG emissions associated with fuel use (average of-1420 lb C0₂e per acre with harvest yields,) while organic canola resulted in the smallest reduction of GHG emissions (average GHG balance of-2261b C0₂e per acre with harvest yields). Removing the GHG value of the coproducts associated with the biofuel production process assessed in this study changed the GHG balance of the four treatments; when coproducts were excluded, only organic sunflower retained a negative GHG balance ( -292lb C0₂e per acre with harvest yields), while all other treatments had a positive GHG balance (71, 239, and 425 lb C0₂e per acre, conventional sunflower, conventional canola, and organic canola, respectively).
This study demonstrated the importance ofunderstanding specific crop types and production methods when quantifying the net GHG benefits of crop-based biofuels. Seed loss at harvest and coproduct valuation emerged as important factors that need to be considered as farm-scale crop-based biofuel production develops in New England.