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.

Contract No. DE-AC36-08GO28308

ARRA Material Handling Equipment Composite 

Data Products

Data through Quarter 2 of 2012

J. Kurtz, S. Sprik, T. Ramsden, C. Ainscough, and G. Saur

Technical Report

NREL/TP-5600-56782

October 2012
NOTICE

This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United 

States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any 

legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process 

disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial

product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its 

endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of 

authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.

Available electronically at http://www.osti.gov/bridge

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Cover Photos: (left to right) PIX 16416, PIX 17423, PIX 16560, PIX 17613, PIX 17436, PIX 17721

 Printed on paper containing at least 50% wastepaper, including 10% post consumer waste.
2

CDPARRA-MHE-01

Fuel Cell MHE Systems Deployed

2010 Q1 2010 Q2 2010 Q3 2010 Q4 2011 Q1 2011 Q2 2011 Q3 2011 Q4 2012 Q1 2012 Q2 0

100

200

300

400

500

600

 14

122

 35

 40

131

 35

 40

131

 60

 76

172

 60

121

221

100

146

221

100

146

258

100

146

258

100

146

258

100

146

258

136

206 206

308

402

467

504 504 504 504

Cumulative Systems Deployed

Fuel Cell Units Deployed - ARRA

Class III

Class II

Class I

Retired Class II

NREL cdparra_mhe_01

Created: Oct-04-12 12:31 PM
3

CDPARRA-MHE-02

Fuel Cell System Operation Hours

0

1

2

3

4

5

6

7

0

250500750100012501500175020002250250027503000325035003750400042504500475050005250550057506000625065006750700072507500 >7500

% Fuel Cell Systems

Cumulative Fuel Cell Operation Hours - ARRA

Combined Fleet Through 2012Q2

25% of FC Systems > 5,260 Hours

FC System

Retired FC System

Fleet Average FC System Hours

NREL cdparra_mhe_02

Created: Oct-04-12 12:42 PM Fuel Cell Operation Hours
4

CDPARRA-MHE-03

Fueling Events by Quarter

0

5

10

15

20

25

30

35

Number of Fills [1,000]

Fueling Events By Quarter - ARRA

2009Q1

2009Q2

2009Q3

2009Q4

2010Q1

2010Q2

2010Q3

2010Q4

2011Q1

2011Q2

2011Q3

2011Q4

2012Q1

2012Q2

 Cumulative Fuelings = 197,991

0

10

20

30

40

50

60

70

Cumulative Fuelings [1,000]

All Sites By Quarter

Cumulative By Site

NREL cdparra_mhe_03

Created: Oct-04-12 1:02 PM
5

CDPARRA-MHE-04

Hydrogen Dispensed by Quarter

0

5

10

15

20

25

30

2009Q1

2009Q2

2009Q3

2009Q4

2010Q1

2010Q2

2010Q3

2010Q4

2011Q1

2011Q2

2011Q3

2011Q4

2012Q1

2012Q2

Hydrogen Dispensed By Quarter - ARRA

Hydrogen Dispensed [1,000 kg]

 Cumulative Hydrogen Dispensed = 141,500 kg 

0

5

10

15

20

25

30

35

Cumulative Amount [1,000 kg]

All Sites By Quarter

Cumulative By Site

NREL cdparra_mhe_04

Created: Oct-04-12 12:13 PM
6

CDPARRA-MHE-05

Refueling Time of Day

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0

1000

2000

3000

4000

5000

6000

7000

8000

Refueling Time of Day - ARRA

Time of Day [hours]

Number of Refuelings

NREL cdparra_mhe_05

Created: Sep-20-12 3:12 PM
7

CDPARRA-MHE-06

Histogram of Fueling Times

0 1 2 3 4 5 6 7 8 9 10 0

0.5

1

1.5

2

2.5x 104

Time (min)

Number of Fueling Events

Histogram of Fueling Times

ARRA Combined Fleet Through 2012Q2

 186,876 Events 

 Average = 2.26 min 

Range of 0

1

2

3

4

5

Site Averages

Average Fueling Times (min)

NREL cdparra_mhe_06

Created: Oct-04-12 1:57 PM Fill data for class 1, 2, and 3 trucks
8

CDPARRA-MHE-07

Tank Pressure Level at Fueling

Tank Pressure At Fill: ARRA

E F

23%

NREL cdparra_mhe_07

Created: Sep-20-12 3:05 PM

1. Some refueling events not recorded/detected due to data noise or incompleteness.

2. The outer arc is set at 30% total refuelings.

3. Full Pressure is either 3600 psi or 5000 psi.

Total refuelings1 Median Tank Pressure (At Fill) = 26% = 81,892
9

CDPARRA-MHE-08

Operation Time between Fueling

0 2 4 6 8 10 12 0

500

1000

1500

2000

2500

3000

3500

4000

4500

 Average: 

 4.7 hours 

Operating Time Between Fuelings - ARRA

Combined Fleet

Operating Hours Between Fuelings1,2

Count

Range of 0

2

4

6

8

10

Site Averages

Average Op Hrs between Fuelings

NREL cdparra_mhe_08

Created: Oct-05-12 8:04 AM Excludes Data > 12 hours

1) Some fueling events not recorded/detected

due to data noise or incompleteness.

2) Data indicative of actual use and does not

represent the max capability of the systems.
10

CDPARRA-MHE-09

Histogram of Fueling Rates

0 0.2 0.4 0.6 0.8 1 1.2 0

2000

4000

6000

8000

10000

12000

14000

16000

18000

Avg Fuel Rate (kg/min)

Number of Fueling Events

Histogram of Fueling Rates

ARRA Combined Fleet 

 186,876 Events 

 Average = 0.32 kg/min 

Range of 0

0.2

0.4

0.6

0.8

1

Site Averages

Average Fueling Rates (kg/min)

NREL cdparra_mhe_09

Created: Oct-05-12 8:48 AM Fill data for class 1, 2, and 3 trucks
11

CDPARRA-MHE-10

Histogram of Fueling Amounts

0 0.5 1 1.5 2 0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2x 104

Amount Fueled (kg)

Number of Fueling Events

Histogram of Fueling Amounts

ARRA Combined Fleet 

 Average = 0.63 kg 

Range of 0

0.5

1

1.5

2

Site Averages

Average Fueling Amounts (kg)

NREL cdparra_mhe_10

Created: Oct-05-12 8:55 AM Fill data for class 1, 2, and 3 trucks
12

CDPARRA-MHE-11

Fuel Cell Operation Hours by Quarter

2010 Q1 2010 Q2 2010 Q3 2010 Q4 2011 Q1 2011 Q2 2011 Q3 2011 Q4 2012 Q1 2012 Q2 0

50

100

150

200

250

Total Operation Hours [1,000]

Fuel Cell Operation Hours by Quarter - ARRA

 Total Hours = 1,248,384 

0

50

100

150

200

250

300

350

400

450

500

Cumulative Fleet Hours [1000]

All Fleets

Individual Fleet

NREL cdparra_mhe_11

Created: Sep-21-12 9:11 AM
13

CDPARRA-MHE-15

Operating Time at Fuel Cell Voltage Levels

0 10 20 30 40 50 60 70 80 90 100 >100 0

5

10

15

20

25

30

35

40

45

% Rated Max Fuel Cell Voltage

% Fuel Cell Operating Time

Operating Time at Fuel Cell Voltage Levels - ARRA

NREL cdparra_mhe_15

Created: Sep-21-12 9:12 AM

1

1) 100% max fuel cell voltage is approximately open-circuit voltage
14

CDPARRA-MHE-16

Operating Time at Fuel Cell Current Levels

0 10 20 30 40 50 60 70 80 90 100 0

5

10

15

20

25

30

% Rated Max Fuel Cell Current

% Fuel Cell Operating Time

Operating Time at Fuel Cell Current Levels - ARRA

NREL cdparra_mhe_16

Created: Sep-21-12 9:12 AM
15

CDPARRA-MHE-17

Operating Time at Fuel Cell Power Levels

0 10 20 30 40 50 60 70 80 90 100 >100 0

5

10

15

20

25

% Rated Max Fuel Cell Power

% Fuel Cell Operating Time

Operating Time at Fuel Cell Power Levels - ARRA

NREL cdparra_mhe_17

Created: Sep-21-12 9:13 AM
16

CDP-MHE-18

Infrastructure Maintenance by Category

7%

7%

8%

9%

9%

14%

15%

31%

Total Events = 1,1261

70% unscheduled

entire

system 16

misc 128

multiple

systems 201

classified

events1 781

Event Count

8%

7%

9%

18%

50%

Total Hours = 6,357

66% unscheduled

hydrogen compressor

feedwater system

dispenser

air system

electrical

control electronics

valves

reformer

NREL cdp_mhe_18

Created: Sep-21-12 2:51 PM

Infrastructure Maintenance By Equipment Type

MISC includes the following failure modes: actuators, safety, seal, unspecified, software,

thermal management, fuel system, fittings&piping, sensors, other
17

CDP-MHE-19

Infrastructure Scheduled & Unscheduled Maintenance by Category

0 50 100 150 200 250

MISC

SENSORS

REFORMER

VALVES

CONTROL ELECTRONICS

ELECTRICAL

AIR SYSTEM

DISPENSER

FEEDWATER SYSTEM

ENTIRE SYSTEM

HYDROGEN COMPRESSOR

Infrastructure Maintenance Scheduled vs. Unscheduled

Number of Maintenance Events by Category

Number of Events

Total Events = 1,126

71% were unscheduled

Scheduled

Total

0 500 1000 1500 2000 2500

MISC

REFORMER

FITTINGS&PIPING

CONTROL ELECTRONICS

SENSORS

VALVES

AIR SYSTEM

DISPENSER

ENTIRE SYSTEM

HYDROGEN COMPRESSOR

Number of Labor Hours by Category

Hours

Total Hours = 6,357

65% were unscheduled Scheduled

Total

NREL cdp_mhe_19

Created: Sep-21-12 2:52 PM

MISC includes the following categories:

ACTUATORS

SAFETY

SEAL

OTHER

UNSPECIFIED

SOFTWARE

THERMAL MANAGEMENT

FUEL SYSTEM

MULTIPLE SYSTEMS

FITTINGS&PIPING
18

CDP-MHE-20

Infrastructure Maintenance by Quarter

 0

 2

 4

 6

 8

10

12

14

16

18

20

Maintenance Events

Average # of Events Per Thousand Fills

09Q1

09Q2

09Q3

09Q4

10Q1

10Q2

10Q3

10Q4

11Q1

11Q2

11Q3

11Q4

12Q1

12Q2

 0

 20

 40

 60

 80

100

120

140

Maintenance Hours

Average Hours Per Thousand Fills

09Q1

09Q2

09Q3

09Q4

10Q1

10Q2

10Q3

10Q4

11Q1

11Q2

11Q3

11Q4

12Q1

12Q2

Scheduled

Unscheduled

Operator

NREL cdp_mhe_20

Created: Sep-21-12 2:52 PM

Average Infrastructure Site Quarterly Maintenance
19

CDPARRA-MHE-21

Average Daily Hydrogen Dispensed by Location

Average Daily Hydrogen Dispensed by Location - ARRA

1-10

11-20

21-30

31-40

41-50

51-60

61-70

71-80

81-90

91-100

>100

NREL cdparra_mhe_21

Created: Oct-04-12 12:14 PM

141,027 kg Hydrogen Dispensed
20

CDPARRA-MHE-22

Average Daily Dispensing Operations by Site

Hydrogen Use 0

10

20

30

40

Avg Daily kg

Hydrogen Use 0

0.2

0.4

0.6

0.8

1

Avg Daily kg/system

Fill Frequency 0

20

40

60

80

100

Avg Daily fills

Fill Frequency 0

0.5

1

1.5

Avg Daily fills/system

NREL cdparra_mhe_22

Created: Oct-04-12 12:15 PM

Average Daily Dispensing Operations by Site - ARRA

Shaded areas represent the min and max site average hydrogen use and fill frequency
21

CDPARRA-MHE-23

Average Daily Fuel Cell Operation Hours per Fleet

A B C D E F G H I J K L 0

2

4

6

8

10

12

Fleet

Hours

Average Daily Fuel Cell Operation Hours per System - ARRA

25th and 75th Percentile

Median

NREL cdparra_mhe_23

Created: Oct-05-12 12:07 PM
22

CDPARRA-MHE-24

Average Daily Fuel Cell Operation Hours per System

0 1 2 3 4 5 6 7 8 9 10 11 12 0

5

10

15

20

Hours of Operation Per Day1

Days of Operation [%]

Fuel Cell System Operation Hours Per Day

0 1 2 3 4 5 6 7 8 9 10 11 12 0

2

4

6

8

10

Average Hours of Operation Per Day1

Fuel Cell Systems [%]

Average Daily Fuel Cell System Operation Hours

54.8% Fuel Cell Systems

Average > 6 Hours Daily

NREL cdparra_mhe_24

Created: Oct-05-12 11:51 AM 1) Excludes 0 hour operation days
23

CDP-MHE-25

Infrastructure Safety Reports by Quarter

0

5

10

15

20

25

30

Events Reported

0

51

102

153

203

254

305

Infrastructure Safety Reports By Quarter

Hundreds of Fills Per Report

2009 Q12009 Q22009 Q32009 Q42010 Q12010 Q22010 Q32010 Q42011 Q12011 Q22011 Q32011 Q42012 Q12012 Q2

Incident2

Near Miss1

Hundreds of Fills Per Safety Report

NREL cdp_mhe_25

Created: Oct-04-12 12:11 PM

1) Near Miss is an event that under slightly different circumstances

 could have become an incident

 -unplanned H2 release insufficient to sustain a flame

2) Incident is an event that results in:

 -a lost time accident and/or injury to personnel

 -damage/unplanned downtime for project equipment, facilities or property

 -impact to the public or environment

 -any hydrogen release that unintentionally ignites or is sufficient to sustain a flame if ignited

 -release of any volatile, hydrogen containing compound (other than the hydrocarbons uses as common fuels)

Total kg of H2 Dispensed: 168,058

Total Reports: 78

Lifetime kg H2

 Dispensed per Report: 2,155
24

CDPARRA-MHE-35

Refuel Events by Day of Week

Sun Mon Tues Wed Thur Fri Sat 0

5

10

15

20

25

Refueling by Day of Week

% of Fills in a Day

NREL cdparra_mhe_35 Day

Created: Sep-20-12 3:42 PM
25

CDP-MHE-41

Infrastructure Safety Categories

0 10 20 30 40 50 60 70

Incident

Near Miss

Number of Reports

Severity

Infrastructure Safety Reports by Severity - All Sites and Report Type

Alarms Only

Electrical Issue

Equipment Malfunction

H2 Release - Minor, NO Ignition

H2 Release - Minor, YES Ignition

H2 Release - Significant, NO Ignition

Non-H2 Release

Operator Protocol

Structural Issue

NREL cdp_mhe_41

Created: Oct-05-12 12:03 PM

An INCIDENT is an event that results in:

 - a lost time accident and/or injury to personnel

 - damage/unplanned downtime for project equipment, facilities or property

 - impact to the public or environment

 - any hydrogen release that unintentionally ignites or is sufficient to sustain a flame if ignited

 - release of any volatile, hydrogen containing compound (other than the hydrocarbons used as common fuels)

A NEAR-MISS is:

 - an event that under slightly different circumstances could have become an incident

 - unplanned H2 release insufficient to sustain a flame
26

CDPARRA-MHE-42

Amount of Hydrogen Dispensed by Day of Week

Sun Mon Tues Wed Thur Fri Sat 0

5

10

15

20

Dispensed Hydrogen [% of total]

Day of Week

Dispensed Hydrogen per Day of Week

0

30

60

90

120

108 kg/day avg

Daily Average [kg]

All Sites

Individual Site

NREL cdparra_mhe_42

Created: Oct-04-12 12:19 PM
27

CDP-MHE-44

Infrastructure Maintenance Labor Hours

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0

 5

10

15

20

25

30

Labor Hours Per Event

Frequency (% of total)

Breakdown of Maintenance Event Labor Hours: Infrastructure

NREL cdp_mhe_44

 0

 20

 40

 60

 80

100

Sites

Event Labor (hrs)

Maximum and Mean Event Labor Hours

for each site.

Mean

Max

NREL cdp_mhe_44

Created: Sep-21-12 2:55 PM

>24

51% of repairs require less than the mean of 7.4 hours of labor.

Median labor hours: 7.1
28

CDP-MHE-45

Infrastructure Reliability Growth

0

0.5

1

1.5

2

2.5

3

Shape Parameter (

β)

1

Overall Site Infrastructure Reliability Growth

1 2 3 4 5 6

1. IEC 61164:2004(E)., Reliability Growth - Statistical Test and Evaluation Methods, IEC. 2004.

2.% change in instantaneous MTBF

Entire history

Last 20% of events

First 120 Days

5

10

15

20

25

Calendar Days in Operation

Instantaneous MTBF

Instantaneous MTBF (Days)

sites

NREL cdp_mhe_45

Created: Sep-21-12 3:04 PM

Sites sorted by Increasing Age

(Calendar Days)

Failure Rate Increasing

Failure Rate Decreasing

Instantaneous MTBF improved for 1 of 6 sites for the last 20% of events.

-1%2

-68%2

-44%2

-70%2

-39%2

124%2
29

CDP-MHE-46

Infrastructure Equipment Category of Safety Events

5%

16%

23%

46%

By Number of Reports

Total Near Miss Reports = 61

6%

6%

88%

By Number of Incidents

Total Incidents = 16 hydrogen compressor

fittings & piping

dispenser

seal

valves

reformer

Misc

NREL cdp_mhe_46

Created: Sep-21-12 2:55 PM

Safety Reports By Equipment Category: Infrastructure

MISC includes the following categories:

FUEL SYSTEM

OTHER

An INCIDENT is an event that results in:

 - a lost time accident and/or injury to personnel

 - damage/unplanned downtime for project equipment, facilities or property

 - impact to the public or environment

 - any hydrogen release that unintentionally ignites or is sufficient to sustain a flame if ignited

 - release of any volatile, hydrogen containing compound (other than the hydrocarbons used as common fuels)

A NEAR-MISS is:

 - an event that under slightly different circumstances could have become an incident

 - unplanned H2 release insufficient to sustain a flame
30

CDP-MHE-47

Infrastructure Maintenance by Mode

5%

6%

6%

6%

6%

6%

6% 7%

8%

8%

8%

10%

12%

Total Events = 1,1261

71% unscheduled

upgrade 42

misc 225

preventative

maintenance 280

classified

events1 579

Event Count

9%

9%

15% 7%

8%

11%

15%

5%

Total Hours = 6,357

65% unscheduled

flow low

pressure high

hydrogen leak

replace failed parts

pressure low

out of calibration

metal fatigue

fluid leak_non_hydrogen

data error

inspect trouble alarm or report

temperature high

flow high

excessive noise

failed closed

operator protocol

NREL cdp_mhe_47

Created: Sep-21-12 2:56 PM

Infrastructure Maintenance By Mode

MISC includes the following failure modes: animal damage, cavitation, debris infiltration,

vandalism, voltage low, power outage, cleanup device failed, electrical short,

maintenance error, manufacturing defect, network malfunction, broken wire, ambient

temperature too low, drive off, unspecified electronics failure, failed open, software bug,

lightning strike, moisture infiltration, other
31

CDP-MHE-48

Infrastructure Mean Time Between Failures

0 25 50 75 100 125 150 175 0

1

2

3

4

5

6

7

8

9

10

Site MTBF1 (Days)

Count of Sites

Site MTBF (Calendar Days In Operation): Infrastructure

NREL cdp_mhe_48

Created: Sep-21-12 2:56 PM

1. Cumulative Mean Time Between Failure
32

CDP-MHE-49

Infrastructure Mean Time Between Scheduled Maintenance

0 25 50 75 100 125 150 175 200 225 250 0

1

2

3

4

5

6

7

8

9

10

Site MTBSM1 (Days)

Count of Sites

Site MTBSM by Calendar Days In Operation: Infrastructure

0 25 50 75 100 125 150 175 200 225 250

0

1

2

3

4

5

6

7

8

9

10

Site MTBPM2 (Days)

Count of Sites

Individual Site MTBPM2 All Sites

0 25 50 75 100 125 150 175

0

1

2

3

4

5

Site MTBU3 (Days)

Count of Sites

Individual Site MTBU3 All Sites

NREL cdp_mhe_49

Created: Sep-21-12 2:56 PM

1. Cumulative Mean Time Between Scheduled Maintenance. Includes Preventative and Upgrades

2

Mean Time Between Preventative Maintenance 3Mean Time Between Upgrade
33

CDP-MHE-50

Infrastructure Reliability Growth by Category

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Calendar Days In Operation

Shape Parameter (

β)*

ELECTRICAL

Failure Rate Increasing

Failure Rate Decreasing

Site

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Calendar Days In Operation

Shape Parameter (

β)*

HYDROGEN COMPRESSOR

Failure Rate Increasing

Failure Rate Decreasing

Site

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Calendar Days In Operation

Shape Parameter (

β)*

VALVES

Failure Rate Increasing

Failure Rate Decreasing

Site

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Calendar Days In Operation

Shape Parameter (

β)*

DISPENSER

Failure Rate Increasing

Failure Rate Decreasing

Site

NREL cdp_mhe_50

Created: Sep-21-12 2:57 PM These represent the top four equipment failure categories from all combined data. *IEC 61164 β
34

CDP-MHE-51

Infrastructure Hydrogen Leaks by Equipment Type

6%

6%

6%

19%

19%

43%

Total Events = 481

100% unscheduled

misc 1

classified1

events 47

Event Count

7%

8%

5%

20%

25%

36%

Total Hours = 447

100% unscheduled

hydrogen compressor

fittings&piping

dispenser

valves

seal

reformer

NREL cdp_mhe_51

Created: Sep-21-12 2:58 PM

Hydrogen Leaks By Equipment Category: Infrastructure
35

CDP-MHE-52

Infrastructure Failures by Mode

0 50 100 150 200 250

HYDROGEN COMPRESSOR

DISPENSER

CONTROL ELECTRONICS

AIR SYSTEM

Event Count

47%*

22%*

12%*

11%*

DATA ERROR

DRIVE OFF

ELECTRICAL SHORT

EXCESSIVE NOISE

FAILED CLOSED

HYDROGEN LEAK

INSPECT TROUBLE ALARM OR REPORT

LIGHTNING STRIKE

METAL FATIGUE

MOISTURE INFILTRATION

OPERATOR PROTOCOL

PRESSURE LOW

REPLACE FAILED PARTS

TEMPERATURE HIGH

UNSPECIFIED ELECTRONICS FAILURE

MISC

0 500 1000 1500 2000

HYDROGEN COMPRESSOR

DISPENSER

CONTROL ELECTRONICS

AIR SYSTEM

Labor Hours

55%*

20%*

8%*

11%*

NREL cdp_mhe_52

Created: Sep-21-12 2:58 PM

Failure Modes for Top Four Infrastructure Equipment Categories

* Percentage of total events or hours, reference CDP 66.

MISC includes the following failure modes: ambient temperature too low, broken wire,

cavitation, debris infiltration, failed closed, flow high, flow low, fluid leak_non_hydrogen,

inspect trouble alarm or report, maintenance error, manufacturing defect, metal fatigue,

moisture infiltration, network malfunction, operator protocol, other, pressure high,

software bug, vandalism, voltage low, other
36

CDP-MHE-55

Infrastructure Mean Time Between Safety Events

0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 0

1

2

3

4

5

6

7

8

9

10

Site MTBSE1 (Calendar Days in Operation)

Count of Sites

Mean Calendar Days Between Safety Reports (MTBSR): Infrastructure

0 250 500 750 1000 1250

0

1

2

3

4

5

Site MTBSI2 (Calendar Days in Operation)

Count of Sites

Mean Calendar Days Between Incidents

0 100 200 300 400 500 600

0

1

2

3

4

5

Site MTBSNM3 (Calendar Days in Operation)

Count of Sites

Mean Calendar Days Between Near Miss

NREL cdp_mhe_55

Created: Sep-21-12 2:59 PM

1. Cumulative Mean Time Between Safety Report (days)

2

Mean Time Between Safety Incident (days) 3Mean Time Between Safety Near Miss (days)
37

CDPARRA-MHE-62

Final Pressure of Hydrogen Fills

200 250 300 350 400 450 0

2

4

6

8

10

12

14

16

18

20

315 bar*

250 bar Fills (200 to 315 bar) 350 bar Fills ( > 315 bar)

Final Pressure [bar]

% of Fueling Events

Fueling Final Pressures

Avg Final Pressure = 256 bar

% of Fills > 250 bar = 74%

Number of Fills = 122275

Avg Final Pressure = 355 bar

% of Fills > 350 bar = 55%

Number of Fills = 47672

Average

Nominal

NREL cdparra_mhe_62

Created: Oct-05-12 1:41 PM *The line at 315 bar separates 250 bar fills from 350 bar fills. It is slightly over 

the allowable 125% of nominal pressure (312.5 bar) from SAE J2601.
38

CDPARRA-MHE-65

Details of Back-to-Back Fills

<0 0 2 4 6 8 10 12 14 16 18 20 0

5

10

15

20

25

30

Simultaneous Fills

Back-to-Back Fills

36 % of fills are within 0-5 minutes of each other

23 % of fills have more than 20 minutes between them

193171 Total Fills

Time Between Fuelings* [min]

# of Fuelings [% of total]

Histogram of Time Between Fuelings

All Sites Combined

Individual Sites

200 225 250 275 300 325 350 375 400 425 450 0

1

2

3

4

5x 104 Final Pressures for Fills with <5 Minutes in Between

# of Fuelings

Final Pressure [bar]

Previous Fill

Next Fill

NREL cdparra_mhe_65

Created: Oct-05-12 12:18 PM *Time is from end of fill to start of next fill.
39

CDP-MHE-66

Infrastructure Maintenance for Delivered Hydrogen

8%

11%

12%

22%

47%

Total Events = 7591

61% unscheduled

entire

system 16

misc 76

multiple

systems 195

classified

events1 472

Event Count

6%

11%

8%

20%

55%

Total Hours = 5,243

61% unscheduled

hydrogen compressor

dispenser

control electronics

air system

sensors

NREL cdp_mhe_66

Created: Sep-21-12 2:59 PM

Delivered Hydrogen Infrastructure Maintenance By Equipment Type

MISC includes the following failure modes: seal, fuel system, safety, thermal

management, electrical, software, fittings&piping, valves, other
40

CDP-MHE-67

Infrastructure Maintenance by Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 0

20

40

60

80

100

120

140

Month

Count of Maintenance Events

Infrastructure Maintenance by Month

Unscheduled

Scheduled

NREL cdp_mhe_67

Created: Sep-21-12 3:00 PM
41

CDPARRA-MHE-68

Fill Counts per Hours

0 5 10 15 20 25 30 35 40 45 0

2

4

6

8

10

12

Number of Fuelings in an Hour

Frequency [% of total]

Number of Fuelings Per Hour - ARRA

NREL cdparra_mhe_68

Created: Sep-20-12 4:10 PM

Average: 7.4 per hour

Median: 5.0 per hour

Max: 39.0 per hour
42

CDPARRA-MHE-69

Fill Amount per Hour

0 10 20 30 40 50 60 0

1

2

3

4

5

6

7

8

9

Amount Fueled in an Hour [kg]

Frequency [% of total]

Hydrogen Dispensed Per Hour - ARRA

NREL cdparra_mhe_69

Created: Sep-20-12 4:21 PM

Average: 4.7 kgs per hour

Median: 3.5 kgs per hour

Max: 52.5 kgs per hour