NREL is a national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC

This report is available at no cost from the National Renewable Energy

Laboratory (NREL) at www.nrel.gov/publications.

Contract No. DE-AC36-08GO28308

July

Economy and Emissions 

Impacts from Solazyme Fuel in 

UPS Delivery Vehicles 

Kenneth Kelly and Adam Ragatz

National Renewable Energy Laboratory

Technical Report

NREL/TP-5400-68896

August 2018
NREL is a national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC

This report is available at no cost from the National Renewable Energy

Laboratory (NREL) at www.nrel.gov/publications.

Contract No. DE-AC36-08GO28308

National Renewable Energy Laboratory

15013 Denver West Parkway

Golden, CO 80401

303-275-3000 • www.nrel.gov

Economy and Emissions 

Impacts from Solazyme Fuel in 

UPS Delivery Vehicles

Kenneth Kelly and Adam Ragatz

National Renewable Energy Laboratory 

Suggested Citation

Kelly, Kenneth, and Adam Ragatz. 2018. Economy and Emissions 

Impacts from Solazyme Fuel in UPS Delivery Vehicles. Golden, CO: 

National Renewable Energy Laboratory. NREL/TP-5400-68896.

https://www.nrel.gov/docs/fy18osti/68896.pdf.

Technical Report

NREL/TP-5400-68896

August 2018
NOTICE

This work was authored by the National Renewable Energy Laboratory, operated by Alliance for 

Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-

08GO28308. Funding provided by USDOE Office of Energy Efficiency and Renewable Energy (EERE), 

Vehicle Technologies Office (EE-3V). The views expressed in the article do not necessarily represent the 

views of the DOE or the U.S. Government.

This report is available at no cost from the National 

Renewable Energy Laboratory (NREL) at 

www.nrel.gov/publications.

U.S. Department of Energy (DOE) reports produced 

after 1991 and a growing number of pre-1991 

documents are available 

free via www.OSTI.gov.

Cover Photos by Dennis Schroeder: (left to right) NREL 26173, NREL 18302, NREL 19758, NREL 29642, NREL 19795.

NREL prints on paper that contains recycled content.
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List of Acronyms and Abbreviations

CO2 carbon dioxide

HHDDT Heavy Heavy-Duty Diesel Truck

HTUF Hybrid Truck Utility Forum Class

HWFET U.S. EPA Highway Fuel Economy Test

LHV lower heating value

NOx nitrogen oxides

NREL National Renewable Energy Laboratory

ReFUEL Renewable Fuels and Lubricants

SCR selective catalyst reduction

ULSD ultra-low sulfur diesel
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Table of Contents

List of Acronyms and Abbreviations ....................................................................................................... iii

List of Figures ............................................................................................................................................ iv

List of Tables .............................................................................................................................................. iv

Background ................................................................................................................................................. 1

Introduction ................................................................................................................................................. 2

Approach...................................................................................................................................................... 2

Results ......................................................................................................................................................... 3

Vehicle Instrumentation and In-Field Data Collection........................................................................... 3

Drive Cycle Analysis.............................................................................................................................. 3

Fuel Properties Testing........................................................................................................................... 5

Heavy-Duty Chassis Dynamometer Testing .......................................................................................... 7

Conclusions............................................................................................................................................... 10

References................................................................................................................................................. 11

List of Figures

Figure 1. UPS package car (left) and day-cab tractor (right)........................................................................ 1

Figure 2. UPS vehicle activity map. ............................................................................................................. 3

Figure 3. Kinetic intensity vs. speed............................................................................................................. 4

Figure 4. Standard drive cycles..................................................................................................................... 5

Figure 5. Fuel distillation profile .................................................................................................................. 6

Figure 6. Fuel density and lower heating values compared with reference values....................................... 7

Figure 7. Fuel consumption .......................................................................................................................... 8

Figure 8. Fuel economy ................................................................................................................................ 9

Figure 9. Relative differences in CO2 emissions, fuel consumption, and fuel economy among the cycles . 9

Figure 10. NOx emissions ........................................................................................................................... 10

List of Tables 

Table 1. Vehicle Specifications .................................................................................................................... 2

Table 2. Vehicle Summary Statistics............................................................................................................ 4

Table 3. Standard Test Cycle Summary Statistics........................................................................................ 5

Table 4. Fuel Properties................................................................................................................................ 6
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Background

UPS is one of the largest users of renewable diesel in the world. In 2015, UPS announced its 

intention to purchase up to 46 million gallons of renewable fuels over three years (UPS 2015). 

Part of that commitment to renewable fuels included renewable diesel supplied by Solazyme. 

Renewable diesel is considered a “drop-in” replacement for petroleum diesel and does not 

require any modifications to existing trucks or equipment. Renewable diesel is held to the same 

standards as conventional fuel and must comply with ASTM International Standard D975 for 

diesel fuel oil.

Two categories of vehicles were investigated during a fleet evaluation. The first was the package 

car, shown on the left in Figure 1. All package cars for this in-field evaluation were model 

P100D and were equipped with Cummins ISB diesel engines on a Freightliner chassis. The 

second vehicle category was the day-cab tractor, shown on the right in Figure 1. The day-cab

tractors had various engine and chassis makes, but all were class 7–8 and used for regional haul 

operations. The vehicle specifications are listed in Table 1.

Figure 1. UPS package car (left) and day-cab tractor (right)

Photo by Dennis Schroeder, NREL 34441

In total, 12 vehicles (six package cars and six day-cab tractors) were instrumented for real-world 

data collection. Data were collected from April 20, 2015, to May 8, 2015. Drive cycle analysis 

was then used to select appropriate standard test cycles for further evaluation on the heavy-duty 

chassis dynamometer at the National Renewable Energy Laboratory’s (NREL’s) Renewable 

Fuels and Lubricants (ReFUEL) Laboratory.
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Table 1. Vehicle Specifications

Package Cars Tractors

Chassis Make Freightliner Custom Chassis NA

Chassis Model MT45 NA

Vehicle Make Utilimaster Kenworth

Vehicle Model P70D T680

Vehicle Model Year 2009 2015

GVWR 15,200 34,700

Engine Make Cummins PACCAR

Engine Model ISB 6.7-200 HP @ 2,400 RPM; 2,600 MX-13

Engine Model Year 2009 2015

Transmission Make Allison Eaton

Transmission Model 1000 HS Automatic FAO-16810S-EP3

Rear Axle Ratio 3.91 2.69

Introduction

NREL’s Commercial Vehicle Technologies Team analyzes near-term advanced technologies and 

provides unbiased performance data to potential vehicle customers, equipment manufacturers,

and the research and development community at large. Clean Cities brings together stakeholders 

in the public and private sectors to deploy alternative and renewable fuels that help advance the 

nation’s economic, environmental, and energy security by reducing petroleum consumption in 

transportation. Together, as part of a joint effort, a team was assembled to instrument, collect, 

and analyze real-world drive cycle data from six package delivery cars and six day-cab tractors 

operating in the Houston area, followed by further fuel economy and emissions analysis at 

NREL’s ReFUEL Laboratory. The goal of this work was to better understand what fuel economy 

and emissions impacts could arise from switching a fleet of vehicles from conventional 

petroleum to synthetic renewable diesel.

Approach

The technical approach for this project follows the general approach for conducting fleet 

evaluations described above. The UPS Solazyme fuel evaluation included:

• Vehicle instrumentation and in-field data collection

• Drive cycle analysis to determine the most representative standard cycles

• Fuel properties testing

• Heavy-duty chassis dynamometer testing of conventional diesel and Solazyme renewable 

diesel to determine fuel economy and emissions impacts.
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Results

Vehicle Instrumentation and In-Field Data Collection

Six package cars and six day-cab tractors were selected for instrumentation at a Houston-area 

UPS depot. Selected vehicles were equipped with Isaac DRU900/908 data recorders on April 17, 

2015. The devices were configured to watch for over 100 public on-board diagnostic parameters 

on the vehicle controller area network bus. Not all parameters were reported, but typically over 

50 parameters are recorded each second, including vehicle speed, transmission gear, engine fuel 

rate and air flow, driver demanded and estimated output torque, and various temperatures and 

pressures throughout the engine and aftertreatment. In addition to controller area network data, 

the devices also collected 1-Hz global positioning system location and speed information. The 

loggers remained on the vehicles until May 8, 2015, capturing three full weeks of vehicle 

operation. Figure 2 shows the collected global positioning system information from both sets of 

vehicles with a closeup of the Houston metro area on the right. 

Figure 2. UPS vehicle activity map

Images from Google Earth

Drive Cycle Analysis

The regional haul day-cab tractors travel between major UPS hubs and cover a large area 

connecting Houston to Dallas, Baton Rouge, Texarkana, Abilene, Austin, and many areas in 

between. The package cars travel from stop to stop making individual deliveries in dense urban 

areas. Therefore, this results in two distinctly and vastly different operating behaviors. Summary 

statistics for the vehicles are shown in Table 2. As expected, the package cars and day-cab 

tractors differ significantly in average speed and kinetic intensity, a measure of drive cycle 

aggressiveness.
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Table 2. Vehicle Summary Statistics

Figure 3 shows a graph of kinetic intensity vs. driving average speed (while the vehicle is in 

motion, excluding stops). The small dots show individual driving days for both types of vehicles, 

and the larger symbols of the same color show vehicle averages, as well as several standard 

cycles that were selected for testing. The Heavy Heavy-Duty Diesel Truck (HHDDT), U.S. EPA 

Highway Fuel Economy Test (HWFET), and SAE J1376 – Commuter cycles were selected for 

the day-cab tractor testing. The HHDDT, NY Composite, and Hybrid Truck Utility Forum Class

4 (HTUF 4) were selected for the package car. However, only the NY Composite cycle was 

tested due to a chassis dynamometer component failure.

Figure 3. Kinetic intensity vs. speed

ISAAC Logger # 3 5 12 13 15 17 29 30 32 33 34 35

Truck Number 147513 143085 148105 147509 147431 147544 274845 273701 271971 274850 274835 271919

Vehicle Type Package Package Package Package Package Package Tractor Tractor Tractor Tractor Tractor Tractor

Total Time [hr] 58.3 75.2 55.0 62.7 65.6 69.5 199.3 11.5 182.0 104.9 205.9 106.7

Idle Time [hr] 9.4 15.7 11.3 9.4 10.5 12.0 10.9 0.9 28.9 6.5 12.3 12.8

Idle Time [%] 16% 21% 20% 15% 16% 17% 5% 8% 16% 6% 6% 12%

Total Dist [mi] 1,162 1,158 766 1,143 1,355 1,354 10,703 654 6,513 5,505 11,649 4,686

Total Work [kWh] 1,119 1,762 1,116 1,470 1,774 1,691 29,374 1,734 11,373 12,433 31,041 10,998

Avg Speed [mph] 19.9 15.4 13.9 18.2 20.7 19.5 53.7 57.0 35.8 52.5 56.6 43.9

BSFC [g/kWh] 287 259 282 265 258 271 198 209 242 203 195 219

Fuel [Gallons] 98.5 140.2 96.7 119.5 140.5 140.5 1783.5 111.2 844.9 775.2 1862.7 739.7

Fuel Econ. [mpg] 11.8 8.3 7.9 9.6 9.6 9.6 6.0 5.9 7.7 7.1 6.3 6.3

KI [1/mi] 0.71 2.81 2.85 1.53 1.04 1.21 0.08 0.13 0.19 0.10 0.09 0.13
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The selected drive cycle time traces are shown in Figure 4, followed by a summary of the 

statistics in Table 3. 

Figure 4. Standard drive cycles

Table 3. Standard Test Cycle Summary Statistics

Fuel Properties Testing

Regular summer blend pump fuel was used as the baseline petroleum diesel for the chassis 

dynamometer tests, and renewable diesel test fuel was supplied directly by Solazyme. Before 

testing began, fuel samples were extracted from each batch of fuel and sent out for analysis. 

Some tests, such as density, cloud point, percent biodiesel, and derived cetane, were conducted 

in-house by NREL’s Fuels Performance Group. The remaining tests were conducted at 

Southwest Research Institute (SwRI). The resulting fuel properties are shown in Table 4. 

Cycle Time (Seconds)

0 200 400 600 800 1000 1200

Vehicle Speed (mph)

0

5

10

15

20

25

30

35

40

New York Composite Cycle

Cycle Time (Seconds)

0 500 1000 1500 2000 2500 3000

Vehicle Speed (mph)

0

10

20

30

40

50

60

HHDDT - No Creep

Cycle Time (Seconds)

0 100 200 300 400 500 600 700 800

Vehicle Speed (mph)

0

10

20

30

40

50

60

US EPA Highway Fuel Economy Test (HWFET)

Cycle Time (Seconds)

0 50 100 150 200 250 300 350

Vehicle Speed (mph)

0

10

20

30

40

50

60

Commuter Cycle (SAE J1376)

Cycle Time Distance Avg Speed Avg D Speed KI Stops Stops

Seconds mi mph mph 1/mi # #/mi

New York Composite Cycle 1,029 2.51 8.8 13.1 4.30 20 7.98

HTUF Class 4 3,336 11.17 12.1 22.5 1.51 28 2.51

HHDDT Cycle Speed Data - Transient Mode 668 2.85 15.3 18.2 1.38 4 1.40

HHDDT - No Creep 2,751 25.92 33.9 37.5 0.17 10 0.39

HHDDT - Cruise Mode 2,083 23.07 39.9 43.2 0.12 6 0.26

US EPA Highway Fuel Economy Test (HWFET) 765 10.26 48.2 48.6 0.22 1 0.10

Commuter Cycle (SAE J1376) 310 4.00 46.3 49.8 0.14 1 0.25

Standard Test Cycle
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Distillation curves are shown in Figure 5. It is worth noting that the Solazyme renewable diesel 

fuel has slightly higher hydrogen content and mass-based heating value, which will later be 

shown to reduce tailpipe carbon dioxide (CO2) emissions and reduce mass-based fuel 

consumption. However, Solazyme’s lower density is significant enough to result in a lower 

volume-based heating value, increasing volume-based fuel consumption and reducing fuel 

economy.

Table 4. Fuel Properties

Figure 5. Fuel distillation profile

Figure 6 shows the fuel density and volumetric lower heating values (LHVs) for both test fuels,

as well as reference values for two additional sources for comparison. The pump fuel for baseline 

testing was shown to have a biodiesel content of 4.61%, and the heating value and density fell 

within the diesel family of fuels in the upper right of the graph as expected. The Solazyme 

renewable diesel test fuel was shown to be on the lighter side of the fuel density spectrum, but it 

was a good match with the renewable diesel Greenhouse Gas, Regulated Emissions, and Energy 

Units ULSD Pump Fuel Solazyme Fuel

D5291 CH Carbon wt% 85.36 83.69

Hydrogen wt% 13.48 14.95

D93 Flash Point °F 144 139

Flash Point °C 62 60

g/cm3 0.834 0.779

°C -16.3 -7.3

% 4.61 2.59

J/g 42,649 43,770

J/cm3 35,556 34,079

DCN 50.5 75.4

Lower Heating Value

Lower Heating Value

Derived Cetane

SwRI + NREL Fuel Analysis

Test Method / Test

Density

Cloud Point

% Biodiesel
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Use in Transportation (GREET) model (Argonne National Laboratory 2008). With the 

assumption of constant engine thermal efficiency, the volumetric LHV will be directly related to 

vehicle fuel economy. The plot shows that renewable diesel has an LHV that is much closer to 

winter blend diesel No. 1 rather than summer blend No. 2. Our test fuel falls in the middle, but 

seasonal and regional variation is to be expected.

Figure 6. Fuel density and lower heating values compared with reference values

Sources: Chevron (2007), Argonne National Laboratory (2008)

Heavy-Duty Chassis Dynamometer Testing

Vehicle testing was performed using the heavy-duty chassis dynamometer at NREL’s ReFUEL 

Laboratory. The chassis dynamometer is capable of simulating transient loads on heavy-duty 

vehicles from 8,000 up to 80,000 pounds at speeds up to 60 miles per hour. To assure the 

accuracy and consistency of road load simulation, an automated dynamometer warm-up 

procedure is performed prior to testing until the dynamometer temperatures stabilize and 

measured parasitic losses in the dynamometer stabilize. After each test run, a loaded coast-down 

procedure is performed to further ensure stability of vehicle and dynamometer parasitic losses 

and accurate road load simulation during testing. Vehicle fuel consumption was measured with a 

gravimetric scale. The fuel returning from the vehicle was cooled with an ambient air-to-liquid 

heat exchanger to maintain consistent temperatures. The scale mass measurements were recorded 

in real time along with all of the test data. Engine intake air was conditioned for pressure, 

humidity, and temperature as well as high efficiency particulate air filtered to eliminate 

background particulate matter. Engine intake air was maintained at 20°C with a dew point of 

12°C, which has a relative humidity of approximately 50%. The intake air pressure was 

maintained at a slight positive gage pressure of about 4–5 millibar above ambient pressure, 

which is typically around 840 millibar for Denver. Vehicle exhaust was diluted via a constant 

volume sample full dilution system. The constant volume sample system relies on sonic flow 
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across orifices to measure exhaust flow rates and dilution ratios. The dilution air for the exhaust 

is supplied by the same system that supplies air to the intake of the engine. Gaseous emissions 

were measured with a Horiba MEXA 7100DEGR Bench.

Cold-start and warm-up tests have been omitted from the results shown in Figures 7–10. Each 

data point is an average of a minimum of three consecutive hot-start tests with a 20-minute soak 

period in between. Error bars on all figures indicate 95% confidence intervals. Figure 7 shows 

the measured gravimetric fuel consumption for all tests. The solid bars indicate tests conducted 

on the day-cab tractor, and the patterned bars indicate tests conducted on the package car. 

Although three cycles were selected for the package car, only one (NY Composite) was 

completed. For the tractors, HWFET and HHDDT exhibited similar results cycle to cycle while 

the Commuter cycle showed an increase in fuel consumption, likely due to the short duration of 

the test and therefore higher weighting of acceleration up to speed relative to cruising. For the 

package cars, the NY Composite cycle (a more aggressive low-speed test, which would typically 

increase fuel consumption) resulted in lower overall fuel consumption—variances in the 

vehicle’s weight and aerodynamic drag properties more than make up the difference.

Figure 7. Fuel consumption

As noted in the fuel properties results, typically a decrease in fuel consumption would result in 

increased fuel economy as the two are inversely proportional. However, in this case, the density 

of the Solazyme renewable diesel fuel is lower than ultra-low sulfur diesel (ULSD) by a greater 

ratio than the gains in fuel consumption, resulting in an increased volumetric fuel consumption 

and lower fuel economy. The fuel economy results are shown in Figure 8.
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Figure 8. Fuel economy

Figure 9 shows the relative changes in tailpipe CO2 emissions, fuel consumption, and fuel 

economy when switching from ULSD to Solazyme renewable diesel fuel for the three day-cab 

tractor tests. Variability in the NY Composite test cycle did not result in a statistically significant 

difference and was therefore omitted. All three cycles show a consistent 4.2% decrease in 

tailpipe CO2 emissions. Fuel consumption and economy showed more variability from cycle to 

cycle, but both trended as expected with Solazyme’s higher mass-based and lower volume-based 

heating values due to its lower density.

Figure 9. Percent change in CO2 emissions, fuel consumption, and fuel economy for renewable 

diesel compared to ULSD

Figure 10 shows average brake-specific tailpipe nitrogen oxide (NOx) emissions for all cycles 

tested. Shown for reference are the applicable family emission limit (FEL) and not-to-exceed 

(NTE) NOx limits for the two different vehicles. All cycles on both fuels are shown to be in 

compliance. The 2015 day-cab tractor conforms to a 0.2 g/bhp-hr NOx emissions standard and

likely shows greater variability because the selective catalyst reduction (SCR) system introduces 

extra variables. Tailpipe emissions can be affected by engine-out conditions as well as SCR 

temperature, feed gas composition, and urea dosing strategy. The absolute emissions levels are 

so low that even a small amount of slip past the catalyst can have a large percentage impact. The 
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2009 package car conforms to a 1.2 g/bhp-hr NOx emissions standard without using an SCR 

system. NOx emissions on the package car are primarily managed via exhaust gas recirculation. 

Absolute-measured NOx emissions are roughly 10 times higher, but the package car 

demonstrated a 4.1% reduction in NOx emissions when switching to Solazyme fuel. However, to 

fully quantify these changes with reduced variability, an engine test stand may be preferred over 

full vehicle chassis testing.

Figure 10. NOx emissions

Conclusions

A three-week in-field data collection period on six day-cab tractors and six package cars yielded 

170 usable days of real-world vehicle operation that were used to select representative standard 

cycles for further testing. Fuel economy and emissions tests at NREL’s ReFUEL Laboratory 

showed that, in general, when switching from conventional petroleum diesel to renewable diesel, 

the thermal efficiency of a cycle remains relatively constant and observed changes in tailpipe 

CO2, fuel consumption, and fuel economy are primarily driven by changes in fuel properties such 

as the hydrogen-to-carbon ratio, density, and LHV. The vehicles tested with Solazyme fuel 

showed a consistent 4.2% reduction in tailpipe CO2, but a 3.5%–4.8% reduction in fuel economy 

compared with local pump diesel. This is consistent with the 4.2% lower volumetric LHV of the 

Solazyme fuel compared to the pump diesel (Table 4). However, pump diesel values could vary 

regionally and seasonally based on local pump fuel blending and composition. The UPS package 

car tested on Solazyme fuel also demonstrated a 4.1% NOx reduction. NOx emissions from the 

UPS SCR-equipped tractor were an order of magnitude lower than the package car but showed 

some variability in results from cycle to cycle. To reduce test variability, especially with SCRequipped engines, and resolve small NOx fluctuations, an engine test stand may be more suitable 

than full vehicle chassis testing.
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References

Argonne National Laboratory. 2008. “Transportation Fuel Cycle Analysis Model, GREET 1.8b.” 

Argonne, IL: Argonne National Laboratory. Released September 5, 2008. 

https://greet.es.anl.gov/.

Chevron. 2007. Diesel Fuels Technical Review. https://www.chevron.com/-

/media/chevron/operations/documents/diesel-fuel-tech-review.pdf.

UPS. 2015. “UPS Makes Substantial Move to Renewable Fuels.” July 29, 2015. 

https://www.pressroom.ups.com/pressroom/ContentDetailsViewer.page?ConceptType=PressRel

eases&id=1438111777421-236.