Are the FAA fuel use and emission facts perceptual or data based?

In a seeming battle between PR and and its own research, the FAA doesn’t agree on what the fuel use and emissions are for the SoCal Metroplex project. The PR department claims that the proposed NextGen changes will result in less fuel and less emissions, the scientists pronounce more and more.

On the FAA website under “Nextgen Snapshots” the following info appears:

Projected Annual Benefits

Source: FAA — Southern California Metroplex Study Team

$7.8 Million

Value of Fuel Savings

2.7 Million Gallons

Fuel Savings

23.3 Thousand Metric Tons

Carbon Savings

These are annual benefits expected to accrue upon completion of the NextGen near-term procedural improvements implemented by the FAA’s Metroplex program. They are based on the FAA’s preliminary assessment of proposed airspace improvements compared to operations in a year before any improvements were made. The value of the projected fuel savings is based on a $2.85 per gallon rate. The data estimates are current as of July 2015.

Pages 129 and 131 of the Draft Environmental Assessment, the official research document used to summarize findings of the modeling, has very different numbers:

Fuel Use:

Fuel burn +8.281 MT more fuel use in 2015
+9.14 MT more fuel use in 2020

“Under the Proposed Action there would be a slight increase in fuel burn (0.33 percent in 2015 and 0.33 percent in 2020) when compared to the No Action Alternative.”

Fuel use

Emission:

+26.13 MT more CO2e Emissions in 2015
+28.84 more CO2e Emissions (MT) in 2020

“The Proposed Action would result in a very slight increase in emissions of CO2e when compared to the No Action Alternative: for 2015, a slight increase of approximately 23 MT of CO2e (0.33 percent); for 2020, a slight increase of approximately 29 MT of CO2e (0.33 percent).”

CO2 Emmisions

Why the discrepancy? Is it possible that the PR department has better data that the actual researchers? The Website claims the data is accurate from July 2015 yet the EA was released in June of 2015. Did something happen in the intervening month that changed the results of the EA? If so, why was the EA not adjusted with this new data?
I lean towards believing the Draft EA is quoting the more correct numbers but then I also believe that facts should have a data-based bias.

FAA, please correct this misleading discrepancy, and issue a press release so the public can know which set of numbers to believe.

 

Edit 12/8/15: In an article by “Aviation Today” dated 6/23/15, after the FAA’s release of the Draft EA, the reporter states “..the agency is still calculating the projected fuel savings and emissions data for the Southern California program.” No response yet from FAA on the real set of numbers.