Comment Log Display

Clerk of the Board
Air Resource Board
1001 I Street
Sacramento, CA 95814
Electronic Submittal:
http://www.arb.ca.gov/lispub/comm/bclisy.php
CC via Email:  aprabhu@arb.ca.gov, jcourtis@arb.ca.gov,
dsimerot@arb.ca.gov 
Comments on: "Detailed California-GREET Pathway for Renewable
Diesel from Midwest Soybeans"
Thank you for the opportunity to comment on the "Detailed
California-GREET Pathway for Renewable Diesel from Midwest
Soybeans". A 2nd Opinion, Inc.'s client, Neste Oil, has sent Anil
Prabhu Neste’s study "Greenhouse gas and energy intensity of
product chain: case transport biofuel" last year. So CARB has
actual data concerning Neste’s NExBTL renewable diesel process. 
We have found some inconsistencies in methodology and what believe
are simply word processing errors.     
1) This path is based upon UOP Process Data.  It is for renewable
diesel produced via hydrogenation technology known as the UOP-HDO
standalone hydrogenation process for renewable diesel II. Neste's
NExBTL process data has not been used in this study.  Neste Oil
will submit Method 2 pathways based upon its production facility
sites and feedstocks at the appropriate time.
2)  One difference in pathways between the UOP and Neste’s actual
case study is the way hydrotreatment and hydrogen production are
integrated into Neste’s refinery site. Neste explained the
allocations in its NExBTL study (page 34). Integrating systems
gives certain benefits concerning energy efficiency and GHG
emissions. This is very productive way to decrease emissions and
should be encouraged. We doubt that these allocations are taken
into account in CARB’s Renewable Diesel study.
3) The CA-GREET methodology assumes that VOC and CO are converted
to CO2 in the atmosphere and includes these pollutants in the total
CO2 value using ratios of the appropriate molecular weights. 
Neste’s study used the International standard ISO 1464 definition
of greenhouse gases. Neste’s reporting is based on its guidance
under which VOC and CO are not included in greenhouse gases. VOC
and CO have also other health, safety and environmental impacts and
these gases are treated separately.
4. ILUC factor needs to be adjusted to reflect higher energy
yields per acre of crop land.  In the Esterified Soyoil study the
preliminary indirect Land Use Change (iLUC) GHG component is
estimated to be 42 gCO2e/MJ of Biodiesel.  Because Renewable Diesel
yields more energy per acre than Biodiesel, the iLUC component for
Soy-based Renewable Diesel should be 40 gCO2e/MJ if 42 is the right
GHG component for Soy-based Biodiesel. (Comments concerning the 42
gCO2e/MJ factor will be covered in another document.)  
Assuming a soy bean yield of 40 bushels/acre the Biodiesel energy
yield per acre is calculated as follows:
+(40 bu beans/acre * 60 lbs beans/bu * 119550 Btu/gal biodiesel) /
(5.7 lbs beans/lb soy oil  * 1.04 lb soy oil/lb biodiesel * 7.4031
lb biodiesel/gal biodiesel * 948.4516527 Btu/MJ) = 6893.25
MJ/acre.
Assuming the same soy bean yield the Renewable diesel energy yield
per acre is as follows:
(40 bu beans /acre * 60 lbs beans/bu *122887 Btu/gal biodiesel) /
(5.7 lbs beans/lb soy oil  * 1.17 lb soy oil/lb renewable diesel *
6.4934 lb renewable diesel/gal renewable diesel * 948.4516527
Btu/MJ) = 7180.74 MJ/acre.
Because land use change is the same for both Biodiesel and
Renewable Diesel and iLUC is measured in gCO2e/MJ the iLUC estimate
for Renewable Diesel is equal to (6893.25/7180.74)*42 or 40
gCO2e/MJ.
While this correction helps a little bit, we remain concerned that
the huge estimated theoretical iLUC factor will discourage the
economic development of one of the few, if not the only, cleaner
burning renewable fuel strategies that reduces NOx emissions.  
Changing the biomass to transportation fuel conversion technology
resulted in a 4% increase in energy yield per acre.  In the energy
industry a 4% improvement in efficiency is huge.  But, it is made
almost negligible when it is compared to the preliminary
theoretical iLUC carbon release.  
5. Fossil carbon credit treatment is inconsistent.  As we compared
the Total Well to Wheel (WTW) energy and GHG carbon emissions from
CARB’s  Biodiesel and Renewable Diesel Pathways we noticed that the
pattern of the WTW and GHG numbers were inconsistent with work done
by other life cycle analysts. We anticipated that Renewable
Diesel’s WTW and GHG numbers would be slightly lower than those of
Biodiesel.  As you can see GHG was higher and there was almost no
difference in WTW.
Biomass-based Diesel Fuel	Total WTW, Btu/mmBtu	GHG, gCO2e/MJ
Biodiesel	1,363,058	26.93
Renewable Diesel	1,353,029	28.80
Fossil CO2 & Btu credits	-57887	-4.22
RD with fossil credits	1,295,142	24.58
This caused us to look for why.  One of the things we found (§7.1)
was Biodiesel received a 3.7 gCO2e/MJ credit for fossil carbon in
the co-product glycerin while Renewable Diesel did not receive a
fossil carbon credit for the co-product renewable propane.  For
consistency Renewable Diesel should also receive a fossil carbon
credit for the carbon content of the renewable propane.
For Renewable Diesel the fossil carbon credit should be 4.22
gCO2e/MJ based upon the following calculation:
(948.451653Btu RD * 0.059 lb C3 per lb RD * 454 gm/lb * 0.85714 gm
C/gm C3 * 3.667gm CO2/gmC) / 18925 Btu/lb RD = 4.22 gmCO2e/MJ.
6. To simplify both the regulatory and compliance processes there
should also be a Fossil energy credit.  Because the renewable
propane will displace fossil propane as fuel, Renewable Diesel
should also receive a fossil energy credit that will reduce the
Total WTW 57,887 Btu based upon the following calculation:
(1000000 Btu RD * .059 lbs C3 per lb RD *18568 Btu per lb C3) /
(18925 Btu per lb RD) = 57887 
We believe the Renewable Diesel Pathway should include the fossil
CO2 and energy credits for fuel co-products.  These co-products
reduce fossil CO2 emissions and energy consumption and therefore
contribute to meeting the overall intent of the LCFS.  Allowing the
credits to be part of the pathway greatly simplifies the
regulations as well as the tracking, recordkeeping and reporting
process.  Doing so also provides more equal treatment for renewable
diesel producers who buy hydrogen and sell propane and those that
integrate the propane and fuel gas recovery into their own hydrogen
production facilities thereby reducing the fossil carbon and energy
footprint of the hydrogen consumed in the conversion process.
   
7. Consistent methodology is a priority. It is not our intent to
cause Biodiesel to lose the fossil credit.  We just want equal
treatment.  That also implies that it is also appropriate to take a
fossil energy credit for glycerin used as boiler fuel.  If
Biodiesel production increases as significantly as the compliance
scenarios indicate, fueling glycerin is a reasonable boundary
assumption.
8. Some life cycle analysts are concerned about mixing allocation
(the primary methodology for both biomass-based diesel pathways.)
and substitution methodologies (fossil carbon credit in Biodiesel
pathway) in the same pathway.  This can be resolved by reducing the
fossil energy and CO2 credits by the amount of fossil energy and
CO2 that was allocated to the co-products.  The Neste LCA’s we
mentioned earlier that integrate hydrogen production essentially
does this.
This will probably result in a small amount of the carbon content
of biodiesel being considered to be fossil carbon.  But, the use of
consistent allocation methodologies for both types of biomass-based
diesel fuel add credibility to the LCFS. 
9. Inconsistent methodologies lead to the question: Are we ready? 
The major problem with items 5, 6, 7 and 8 is that Life Cycle
Analysis methodology may not be consistent, mature and stable
enough for use in regulations.  The different treatment of the
fossil carbon credit in the two pathways proves they are not
consistent.  The need to change at least one if not both of the
pathways is an indication that they are not mature and stable. 
Fortunately both pathways were labeled as being “…a preliminary
estimate of the carbon intensity for the fuel derived from soybeans
presented in this document.  At this time…”  Can we have
regulations based upon “preliminary estimates”?  Or, does the
regulatory process need to slow down?
10.  When will Table A on Page 7,Table Q on Page 15 and Table 7.01
on Page 61 be revised to reflect the NOx and VOC emissions findings
from the “Biodiesel and Renewable Diesel Emissions Study”?  Also,
the methodology used to measure exhaust hydrocarbons in the study
does not measure exhaust oxygenates.  How does CARB plan to convert
the exhaust oxygenates that are probably more concentrated in
biodiesel exhaust than in renewable diesel exhaust to CO2
equivalents? 
11.  Our remaining comments address what we believe to be word
processing errors.
Table M on Page 14: Should Methanol be Hydrogen? 
Table 1.02 on Page 19:  The Soy Oil to RD (lb oil/lb RD) should be
1.17
Page 19: In the mmBtu RD/bushel soybeans calculation just below
Table 1.02, 0.17 should be replaced with 1.17 and the result,
0.163448 looks like a leftover from the biodiesel pathway.
Table 1.04 on page 21: All the references to Table 1.04 should be
to Table 1.03.  Total energy due to soybean farming should be,
Btu/mmBtu = 26564 Btu/bu / 0.169685 = 156549.  Total adjusted
energy also has problems.  RD production allocation factor for RD
II is 94.5% and the loss factor is 1.000045 as stated in the Note
after the table. By using these values and the value 156549 the
total adjusted energy should be 67611 Btu/mmBtu. We cannot get the
value 67180 using any combination of the numbers (correct or not
correct).
Table1.08 on page 26: All the references to Table 1.08 should be
to Table 1.07.  The entry under 
- Diesel, Formula: 2926 should be replaced by 3868 
Table 5.01, page 51:  Replace Transesterification with
Hydrogenation 
Appendix B, page 66:  Replace Soyoil Transesterification data with
Soyoil Hydrogenation data 
If you have questions you may contact Cal Hodge at
A2ndOpinionInc@aol.com and/or Riitta Lempiainen at
Riitta.Lempiainen@nesteoil.com .