NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Ali A. Jalalzadeh-Azar

ASME

3rd International

Conference on

Energy Sustainability

July 19-23, 2009

San Francisco, CA

NREL/PR-560-46368

Distributed Hydrogen Technologies for 

Commercial Buildings and Vehicle Refueling
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Premise of Multi-Faceted Analysis

Successful implementation of hydrogen technologies 

requires macro- and micro-level analysis.

 Energy- and water-resource assessment is important 

for infrastructure development.

 Effective hydrogen utilization on the demand side can 

influence the economic and environmental attributes of 

hydrogen technologies.

 Use of a joint hydrogen production facility for stationary 

and transportation applications can provide an 

opportunity for overall cost reduction—a critical criterion 

for accelerating market acceptance.

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Objectives

 Perform energy analysis of H2-based DG 

systems serving commercial buildings

 Address resource requirements—energy and 

water—for the DG systems.

 Investigate the potential economic benefits of 

integrated stationary and transportation 

applications in the context of tri-generation. 

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System Characteristics

Storage

Electricity Nat. Gas Water

CHP Heat 

Recovery

Fuel Cell

• PEMFC

• PAFC

• SOFC

H2 Production

Natural Gas

Reformation

(SMR)

H2

Building Equipment

STATIONARY

H2 Vehicle Fueling

TRANSPORTATION

NG

H2

Elec.Elec.

Storage

 Distributed generation (DG) 

system consists of a steam 

methane reformer, and a fuel 

cell system—PEMFC, PAFC, 

or SOFC.

 DG system generates 

electricity for commercial 

buildings; excess H2 is used 

for refueling.

 Heat recovery from PAFC 

and SOFC is available for 

internal and external 

applications.

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Approach

 Perform thermodynamic analysis of the three H2-

based DG systems for commercial buildings using 

the DOE Benchmark Load Profiles: 

• FCDG: A basic system with no heat recovery—all FC 

types.

• CHP: FCDG plus heat recovery for end-use equipment—

PAFC and SOFC.

• FCDG-ADV: Advanced system incorporating SOFC and 

internal heat recovery for H2 production

CHP

FCDG

PEMFC

PAFC

SOFC

NG Reform.

H2

H2

Heat

Elec.

H2

Elec. =

=

SOFC FCDGADV

H2

Heat

Integrated / Internal Heat Recovery

H2

Elec. = NG Reform.

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Approach (cont.)

 Extrapolate the results of system-level analysis for 

national-level assessment of resource requirements 

stemming from adoption of DG technologies for 

commercial buildings using the EIA data.

 Evaluate the primary energy and environmental impact 

of the DG systems.

 Investigate the economics of a consolidated H2-

production facility serving both stationary & 

transportation applications in commercial communities 

consisting of a H2 refueling station and an EIA-based 

group of buildings—hospitals, supermarkets, offices, 

and retails.

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Approach (cont.)

Two models are conceptualized for integration:

 Model I: A properly sized H2 production facility for 

buildings also supplies the excess hydrogen during the 

off-peak periods to the community refueling station. 

 Model II: The FCV refueling

station is oversized in H2-

production capacity to meet

the aggregate demand of 

the buildings within the

community. 

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Key Assumptions

System 

Category

Type Efficiency 1

Operating 

Temp. 

(oC)1

Application

Distributed 

Hydrogen 

Production

NG Reformer 0.75 N/A FCDG, FCDG-ADV, and 

CHP

Distributed Power 

Generation

PEMFC 0.42 90 FCDG

PAFC 0.48 190 FCDG and CHP

SOFC 0.56 600 FCDG, FCDG-ADV, and 

CHP

End-Use Systems

Electric Cooling 3.0 COP N/A Baseline, FCDG, FCDGADV, and CHP

Gas-fired 

Furnace/ Space 

Heating2

0.80 AFUE 80 Baseline, FCDG, FCDGADV, and CHP

Gas-fired 

Service HotWater Heater2

0.62 AFUE 50 Baseline, FCDG, FCDGADV, and CHP

1. Nominal values

2. Gas-fired systems are retrofitted to accept non-combustion heat source in the CHP system

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Results and Discussions

 EIA Data 

 Resource Assessment

 Vehicle Fueling Capacity

 Energy and Environmental Benefits

 Economic Impact of System Integration

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Relative Energy Use of Buildings—EIA Aggregates

0

10

20

30

40

50

60

70

80

Education Health Care

(Inpatient)

Lodging Office Retail (other

than mall)

Food

Service

Combined

Building Type

Relative Energy Consumption, % 

0

2

4

6

8

10

12

14

16

Ratio of Elec. Primary Energy to Nat. Gas

 Rel. Elec. Cons. (% of Total Delivered Commer. Elec. Cons.)

 Rel. Nat. Gas Cons. (% of Total Delivered Commer. Nat. Gas Cons.)

 Ratio of Elec. Source Energy to Nat. Gas

 EIA-aggregated electricity use of office buildings has he highest 

share—followed by education building type. 

 On average, the primary energy for electricity generation is about 

5.5 times the natural gas energy for selected building types. 

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Resource Assessment at 20% Market Share

-20

-10

0

10

20

30

40

50

60

FCDG FCDG-ADV CHP

System

Change in Delivered Energy Use, % 

 Electricity

 Natural Gas

Market Share: 20% of selected bldg. types

 About 16% reduction in the total grid-electricity use for commercial 

buildings is expected with any of the DG alternatives. 

 Alternative FCDG-ADV requires about 29% more natural gas 

compared to 43% and 49% for CHP and FCDG, respectively. 

 Water consumption

increased by less

than 3% at the site.

Note: An overall decrease 

in water usage is possible

when considering the wateruse displacement at the 

power plants.

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-200

-100

0

100

200

FCDG FCDG-ADV CHP

System

Change in Energy Use, 109 kWh Elec., 109 

m3 NG / Yr.

 Electricity

 Natural Gas

Market Share: 20% of selected building types.

Resource Assessment (cont.)

 Resource requirements—absolute values. 

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-14

-12

-10

-8

-6

-4

-2

0

2

4

6

FCDG FCDG-ADV CHP 

Scenario

Change in Primary Energy Use and

GHG Emissions, %

 Primary Energy

 GHG Emission

Market Share: 

20% of selected bldg. 

t pes NG Reformation

Energy and Environmental Impact at 20% Market Share

 The advanced DG system, FCDG-ADV, offers the greatest 

reduction in primary energy use and GHG emissions, followed by 

the CHP system. 

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Vehicle Refueling Capacity / Model I—Building Level

0

100

200

300

400

500

600

Phoenix

Los Angeles

Boulder

Miami

Atlanta

Chicago

Baltimore

Minneapolis

Houston

Seattle

Location

No. of FCVs / GWh

0

100

200

300

400

500

600

% of Occupants with FCVs

 Office, % of Occupants

 Office, Per GWh

 Hospital, Per GWh

Floor Area: 

~10,000 m2

PEMFC

PAFC

SOFC

Typical for all locations

 Under Model I integration, excess H2 capacity and the FC 

efficiency are negatively correlated. (The opposite will be the case 

for fixed H2 production rate for all FC types.) 

 An office building offers a greater refueling capacity per GWh of the 

annual energy consumption than hospital.

 For office buildings, 

excess on-site H2 prod. 

can meet and even 

surpass the hydrogen

demand of the occupants’ 

FCVs (13,000 miles/yr at

50 miles/kg H2),

Office occupancy: 

1 person per 26 m2. 

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Vehicle Refueling Capacity / Model I—EIA Community

0

50

100

150

200

250

300

350

400

Los Angeles Atlanta Chicago

Location

Avg. Vehicle Fueling Capacity, kg H2/day

Hospitall

Retail

Office

Supermarket

PEMFC

H2 production rate meets the baseline 

design electrical load.

EIA-based total floor area:

 ~10,000 m2

0

100

200

300

400

500

600

Los Angeles Atlanta Chicago

Location

Avg. Vehicle Fueling Capacity, kg H2/day

FCDG / PEMFC

FCDG / SOFC

Reference Commercial Community

Total floor area: ~10,000 m2

H2 production rate meets the baseline 

design elec. load.

 Community of hospitals, retails, 

offices, and supermarkets

EIA-aggregated floor area: 10,000 

m2

 Office buildings have the largest 

share of the total fueling capacity.

 Commercial buildings with a total 

floor area of 50,000 m2 can 

support a 1,500 kg/day fueling 

station in LA and a larger station 

in Atlanta and Chicago when 

PEMFC is used in Model I.

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0

20

40

60

80

100

0 20 40 60 80 100

Vehicle Refueling Station Capacity Increase, %

Potential Cost Savings, $ / m2

0

20

40

60

80

100

% Savings

 Savings, SF = 0.6

 Savings, SF = 0.8

 % Savings, SF = 0.6

 % Savings, SF = 0.8

Cost Scaling Range

Commercial Community--Los Angeles

Natural Gas Reform., PEMFC for Buildings

Economic Impact of System Integration

 Model I supporting a 50,000-m2 commercial community can avoid 

installation of a 1,500-kg/day refueling station—saving about $1M.

 In Model II, the refueling station oversized by 60% (i.e., 1,500 x 

1.60 kg/day) can support a 30,000-m2 commercial community—

saving only about

$0.5M.

Model II:

Scaling Ratio: 

1.30 – 1.70

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Conclusions

 Advanced system, FCDG-ADV, incorporating SOFC and internal heat 

recovery yields significantly higher amounts of primary energy and 

GHG reductions than the other two alternatives, particularly FCDG.

 With water recovery management in place, the net increase in on-site 

water consumption is estimated to be less than 3%.

 Integration of stationary/transportation applications can lead to 

significant cost reduction by avoiding stranded investment in H2 

production.

 The integration Model I (using buildings’ excess H2 for FCV refueling) 

is economically more tenable than Model II (scaling up the FCVrefueling production facility to support the community’s commercial 

buildings). 

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Questions / Comments ?

Thank you!

Ali.Jalalzadeh@nrel.gov

National Renewable Energy Laboratory Innovation for Our Energy Future