Comment Log Display

While fully supporting the spirit of the proposed LCFS, I urge ARB
to reconsider a LCFS credit for light-duty diesel vehicles (LDDVs).
LDDVs can utilize renewable diesel fuel (FAHC) that by ARB’s own
analysis potentially has the lowest lifecycle carbon intensity (CI)
of any fuel considered in the proposed  LCFS (15 g CO2e/MJ per
Table VI-4); a lower CI than cellulosic ethanol (20.4 g CO2e/MJ),
electricity (34.9 g CO2e/MJ), and hydrogen (33.09 g CO2e/MJ), even
taking into account generous power train efficiency advantages
(EER) assigned by ARB to electric and hydrogen fuel cell vehicles
compared to diesel power trains.

Thus, contrary to the assertion on page X-5, §2, LDDVs do
potentially provide significant long term benefits of promoting
significantly lower carbon fuels (e.g., FAHC renewable diesel fuel)
and more energy efficient vehicles. The assertion that “[t]he
increasing efficiency of gasoline vehicles will continue to close
the efficiency gap separating gasoline from diesel vehicles...” and
“...eliminate most, if not all, of the credits” (page VI-17)
assumes for no apparent reason that the efficiency of diesel
engines will not also improve, something that is contradicted by
engine parts suppliers (for both gasoline and diesel vehicles) like
Bosch (see, e.g.,
http://wardsautoworld.com/ar/auto_european_brands_bullish/). Diesel
engines can also be adapted to hybrid power train systems in LDV
applications for even greater vehicle efficiency.

According to ARB staff estimates, LDDVs have 15% to 20% lower CO2
emissions than equivalent LDGVs (footnote #49, page VI-16). This in
conjunction with the CI reduction of renewable diesel (FAHC) would
result in at least an 87% reduction in CO2e emissions compared to
baseline LDGVs running on CaRFG ((15 g CO2e/MJ ÷ 95.85 g CO2e/MJ) X
(1 - 0.15) = 0.133; 1 – 0.133 = 0.867 = 86.7% reduction). This
would potentially exceed Governor Schwarzenegger’s long term goal
of reducing GHG emissions by 80 percent by 2050 for this
application (page ES-3).

The objective should be to reduce CO2 emissions as much and as
soon as practicable, not just meet an arbitrary goal of 10%
reduction by 2020. It appears that this could best be accomplished
in the short- to medium-term by encouraging diesel vehicles which
in turn would be capable of using a very low CI fuel (FAHC) with no
modifications required.

It would seem “double crediting” would be completely justified
because of the greater efficiency of the compression-ignition ICE
over the spark-ignition ICE plus the capability of using the lowest
carbon intense fuel identified by ARB. A LCFS credit for LDDVs may
encourage more manufacturers to offer diesel engine options in the
U.S. in at least some of their vehicle lines.

As a disclaimer, I am in no way associated with the automotive
industry.

Thank you for your consideration of these comments.


Respectfully submitted,

L. Carl Marz, Certified Consulting Meteorologist