Ford commercializing new method of attaching windshields; reduction of VOCs and lower costs
Rice researchers show ocean could have contained enough methane to cause drastic climate change 56M years ago

Study finds renewable fuel mandates alone not likely to lower carbon intensity of biofuels; the importance of localized LCAs and optimized low carbon fuel standards

A new lifecycle analysis (LCA) by a team from the University of of Cambridge (UK), the Great Plains Institute, and the University of Minnesota suggests that renewable fuel mandates such as those currently enacted by 12 states are not likely to lower the emissions of biofuels unless they provide a direct incentive for refiners to reduce greenhouse gas (GHG) emissions.

In a paper published in the journal Energy Policy, the team suggests that more effective policies would evaluate fuels at the refinery level, thereby creating incentives for GHG emissions to be lowered through competition as low GHG emission fuels have higher economic value to blenders. Ultimately, the authors suggest, states can encourage the reduction of fuel GHG emissions by developing policies, such as a low carbon fuel standard (LCFS), that encourage incremental improvements in corn ethanol in the short term and in the medium term by switching to cellulosic-derived fuels.

As the US moves towards lowering greenhouse gas (GHG) emissions from its transportation fleet, states may evaluate policies, such as low carbon fuel standards (LCFSs), to lower GHG emissions from transportation fuels. Policies designed to reduce the average fuel carbon intensity (AFCI) can achieve significant GHG emissions reductions in the transportation sector when combined with strategies to increase vehicle efficiency and lower the rate of growth of vehicle activity. Previous analyses have indicated that without policies such as LCFSs, GHG emissions from transportation would not be significantly reduced even if economy-wide GHG cap and trade policies were enacted.

...Fuels are often evaluated by lifecycle analyses (LCAs) using average national data, but more accurate and specific methods and data are available to perform LCAs for fuels on a state and individual refinery basis. Localized differences in electrical generation, crude oil sources, biomass production practices, refinery efficiencies, and other parameters may cause the fuel carbon intensity (FCI) of specific fuel pathways to differ significantly from the national average. Development of FCIs using state- or refinery-specific data could aid in the development of policies that can lower transportation emissions of states in accordance with their unique profiles.

—Boies et al.

The study examined the FCI of transportation fuels on a lifecycle basis within a specific state, Minnesota, and compared the results to FCIs using national averages. Using data compiled from 18 refineries over an 11-year period, the team found found find that ethanol production is highly variable, resulting in a 42% difference between carbon intensities.

Historical data suggested that lower biofuel FCIs are possible through incremental improvements in refining efficiency and the use of biomass for processing heat. Stochastic modeling of the corn ethanol FCI showed that gains in certainty due to knowledge of specific refinery inputs are overwhelmed by uncertainty in parameters external to the refiner, including impacts of fertilization and land use change.

The authors then incorporated the LCA results into multiple policy scenarios to demonstrate the effect of policy configurations on the use of alternative fuels. These results provided a contrast between volumetric mandates—i.e., renewable fuel standards—and LCFSs.

Primary conclusions of the study with respect to LCAs are:

  1. LCA should be done at as local a level as possible.

  2. Uncertainty analysis is important to determine the risk of fuels’ environmental impacts.

  3. Refiners are improving efficiency.

  4. The efficiency improvements of refiners are being dwarfed by uncertainties such as land-use change and NO2 emissions from fertilizers.

Policies such as low carbon fuel standards that seek to reduce fuel GHG emissions on a state or regional scale require that fuels be evaluated on an equivalent basis. The work presented here demonstrates that fuels within a state can have different FCI even when produced using similar pathways. The variation in corn ethanol FCIs was found to be largely a result in differences in the source of process heat, energy efficiency of production and ethanol yield. The historic trends in fuel production show that it is likely that reductions in corn ethanol FCI can be made through incremental improvements if given the proper incentives. These improvements, however, are insignificant when compared to the current range of uncertainties beyond the refiners’ control (e.g. emissions associated with LUC [land use change] and N2O from fertilizers) and thus highlight the need for further study of critical para- meters. While it is unlikely that policies will be crafted to include uncertainty analysis, these results highlight that FCI point estimates alone do not guarantee accurate accounting of possible GHG reductions from different fuels and will thus hamper effective choices of fuel alternatives.

—Boies et al.

With respect to policy modeling, the authors concluded that:

  • Carbon-intensity based policies (such as LCFS) outperform existing volume mandates (such as RFS) in carbon reductions.

  • Specific policy configurations matter—i.e., not every LCFS is the same. Some might be optimized for conventional oil, some for cellulosic ethanol.

Ultimately, the rate at which alternative fuels are produced and decarbonized will largely be driven by policies such as an LCFS. This work demonstrates how different structures of an LCFS can affect the levels of biofuel production and their resulting emissions.

—Boies et al.


  • Adam M. Boies, Dane McFarlane, Steven Taff, Winthrop F. Watts, David B. Kittelson (2011) Implications of local lifecycle analyses and low carbon fuel standard design on gasohol transportation fuels, Energy Policy, Volume 39, Issue 11, Pages 7191-7201, doi: 10.1016/j.enpol.2011.08.040



The best way to reduce carbon intensity is to stop (or reduce) burning liquid fuels, coal and NG. Switching from fossil to bio-fuels will help but the reduction obtained could be more than offset with added power plants and larger future fleets.

Cleaner e-energy production (Solar-Wind-Hydro-Geothermal etc) and ground vehicles, trains, machinery, ships, etc electrification are essential if we seriously want to lower carbon emissions and other air and water pollution.

Private industries will only do it on a massive scale if they can get higher profits out of it. Otherwise, it will be business as usual with more 'clean coal power plants', 'clean blue NG and SG', 'ultra clean ICE vehicles' and other false PR campaigns.


They are not going to do it with corn ethanol, H2 from wind and solar could help, but we are not there yet.


SJC, we're a lot further than you think. And a heads up, now six States have quit the Western Climate Initiative - strongly indicating climate is not an issue - but energy is.


six States have quit the Western Climate Initiative - strongly indicating climate is not an issue

Well, that's one way to spin it. Another way would be to say these 6 states will now be working with a larger group with 13 other states and four Canadian provinces in a new initiative called North America 2050, which has the same goals but doesn't restrict itself to cap&trade and has a more open methodology.


Study finds the marxist / socialist regimes want to take away more freedom under the guise of saving the surprise there.


sjj......ALL have contributed to the current progressive degradation. It will only be reversed if we ALL but aside our religious and political (often twisted) believes and change our ways.

It has (and should have) nothing to do with race, religion, politically system in place etc etc. It is more a matter of human nature, greed, speculation and similar worldwide traits.


ai_vin is correct that there is a new initiative that has eliminated carbon cap n trade. The new focus is on energy and transitioning away from fossil fuels. This is something that all parties should be capable of agreeing to (except oil interests.)

The comments to this entry are closed.