National Renewable Energy Laboratory 

Innovation for Our Energy Future 

A national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

NREL is operated by Midwest Research Institute ● Battelle Contract No. DE-AC36-99-GO10337 

Assessment of the Technical 

Potential for Achieving ZeroEnergy Commercial Buildings 

Preprint 

B. Griffith, P. Torcellini, and N. Long 

National Renewable Energy Laboratory 

D. Crawley and J. Ryan 

U.S. Department of Energy 

To be presented at ACEEE Summer Study 

Pacific Grove, California 

August 14−18, 2006 

Conference Paper 

NREL/CP-550-39830 

June 2006 
NOTICE

The submitted manuscript has been offered by an employee of the Midwest Research Institute (MRI), a 

contractor of the US Government under Contract No. DE-AC36-99GO10337. Accordingly, the US 

Government and MRI retain a nonexclusive royalty-free license to publish or reproduce the published form of 

this contribution, or allow others to do so, for US Government purposes. 

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

Available for a processing fee to U.S. Department of Energy 

and its contractors, in paper, from: 

U.S. Department of Energy 

Office of Scientific and Technical Information 

P.O. Box 62 

Oak Ridge, TN 37831-0062 

phone: 865.576.8401 

fax: 865.576.5728 

email: mailto:reports@adonis.osti.gov

Available for sale to the public, in paper, from: 

U.S. Department of Commerce 

National Technical Information Service 

5285 Port Royal Road 

Springfield, VA 22161 

phone: 800.553.6847 

fax: 703.605.6900 

email: orders@ntis.fedworld.gov

online ordering: http://www.ntis.gov/ordering.htm

Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste
Assessment of the Technical Potential for Achieving 

Zero-Energy Commercial Buildings1

Brent Griffith, Paul Torcellini, and Nicholas Long, 

National Renewable Energy Laboratory 

Drury Crawley and John Ryan, 

U.S. Department of Energy 

ABSTRACT 

The U.S. Department of Energy’s (DOE) Building Technologies Program has adopted 

the goal of making zero-energy commercial buildings (ZEBs) marketable by 2025. The National 

Renewable Energy Laboratory (NREL) conducted an assessment of the entire commercial sector 

to evaluate the technical potential for meeting this goal with technology available in 2005 and 

projected forward to possible technology improvements for 2025. The analysis looked at the 

technical feasibility of ZEBs, limitations in market penetration and utility grid structures 

notwithstanding. 

The core of the evaluation was based on creating 15-minute, annual simulations based on 

5,375 buildings in the 1999 Commercial Buildings Energy Consumption Survey Public Use Data 

and the current ANSI/ASHRAE/IESNA Standard 90.1-2004. These baseline-building models 

were then used to develop alternate ZEB scenarios by applying sets of available technologies and 

practices and projected improvements after 20 years. 

The results show that the ZEB goal is technically achievable for significant portions of 

the commercial sector. Using today’s technologies and practices, the technical potential is that 

22% of the buildings could be ZEBs. With projected 2025 technologies, the technical potential 

is that 64% of the buildings could be ZEBs. If excess electricity production could be freely 

exported to the grid, then with the projected 2025 technology in every building, the commercial 

sector could generate as much as 37% more energy than it consumes. The results suggest that 

the ZEB goal is feasible for the sector as a whole and that research should be implemented to 

overcome hurdles to achieving the goal. 

Introduction 

The Energy Information Agency’s (EIA) Annual Energy Outlook 2006 (AEO 2006) 

predicts that energy use in the commercial sector will grow by 1.6% per year, driven by the 

increasing floor area needed for economic expansion and population growth. AEO reports that 

the commercial sector is the fastest growing demand sector—its growth rate is twice that of the 

residential sector. To address the resulting problem of increasing burden on the nation’s energy 

 

1 This work has been authored by an employee or employees of the Midwest Research Institute under 

Contract No. DE-AC36-99GO10337 with the U.S. Department of Energy. The United States Government 

retains and the publisher, by accepting the article for publication, acknowledges that the United States 

Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the 

published form of this work, or allow others to do so, for United States Government purposes. 

1
system, the U.S. Department of Energy’s Building Technologies (BT) Program has adopted the 

goal of market-viable, new commercial buildings with zero net energy impact (ZEBs) by 2025 

(DOE 2005). Successfully meeting the ZEB goal would allow commercial sector energy 

demand to be decoupled from economic growth and help to mitigate risks to economic expansion 

that may arise from possible future constraints on energy supply and fossil fuel-related 

emissions. 

This paper looks at the potential to achieve ZEBs in the commercial building sector. 

What might be achieved if all commercial buildings strived toward the ZEB goal? How low can 

energy use go within the sector? Which subsectors can meet the goal and which need additional 

energy savings to achieve the goal? 

This assessment determines the technical potential for the commercial sector as a whole 

by evaluating collections of known technologies and practices and carefully modeling system 

interactions with whole-building simulation. 

Methodology 

For an assessment of the ZEB goal to be valuable to BT, national-scale results are 

required. To meet this need, we used a method with a large number of individual building 

models that were intended to represent the entire commercial sector. Various researchers have 

used this approach, which has been referred to as stock aggregation, bottom-up, and backcasting 

(Briggs, Crawley, and Belzer 1987; Briggs, Crawley, and Schliesing 1992; Crawley and 

Schliesing 1992, Huang and Franconi 1999). We developed a set of building models that 

represent all building types and locations based on the 1999 Commercial Buildings Energy 

Consumption Survey (CBECS) public use data (EIA 2002). Our analysis takes parameters from 

the CBECS dataset, creates building models, and determines the technical potential for energy 

performance based on current technologies and practices and on projected performance levels 20 

years hence. Such technical potential studies establish the maximum technically achievable 

energy savings. They do not include any consideration of economic feasibility. Technical 

potential studies are useful in establishing broad research goals and targets of opportunity for 

energy R&D programs. Economic analysis can be used later to establish the initial cost levels 

needed to achieve significant market penetration. Multiple scenarios were used to develop an 

understanding of the relative importance of various technologies for achieving high performance. 

The essence of the ZEB concept is a building designed in such a way that on-site energy 

consumption is reduced to a level that can be entirely met by on-site renewable energy 

production over a typical one-year period. This study assumes that the building can export 

energy to the utility grid—realistically, grid limitations may prohibit this. Photovoltaic solar 

electric power systems (PV) were selected as the technology for on-site energy production 

because it is the probably the most widely applicable renewable technology—the roofs of 

virtually all buildings are viable sites for PV. For this research, we used a net site energy 

definition. A net site ZEB produces as much energy annually as it uses when accounted for at the 

site (natural gas energy use is offset with on-site electricity generation at a 1:1 ratio). 

Analysis Framework 

Because building energy use is complex, simulation tools are needed to model all the 

interactions between systems, components, occupants’ activities, and weather. This is especially 

2
important when evaluating the combined performance of collections of technologies and 

practices. EnergyPlus (Crawley et al. 2001) was selected because it can model PV systems and 

advanced building technologies in an integrated manner. In some cases alternate scenarios were 

evaluated by comparing the annual simulation results for baseline building models to the results 

for models that reflect the addition of ZEB technologies and practices. 

Although simulations can model the energy performance of buildings, simulation studies 

often deal with only a handful of buildings in a few locations. This limitation makes it difficult 

to extrapolate results and draw valid conclusions for the sector as a whole. This study overcame 

this limitation by using a methodology based on a large set of 5,375 models derived directly 

from the sample buildings in the public use data from 1999 CBECS. The primary benefit of 

directly using CBECS is that the CBECS weighting factors provide a robust way of obtaining 

national results from simulations of individual buildings. For example, to aggregate results for 

the national average for percent savings in net site energy (netEUI) for a particular LZEB 

scenario, we use the weighting factor and floor area data from CBECS in the following manner: 

∑( )

∑

=

=

×

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛

× × ⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ −

= N

i

i i

N

i

i i

i base

i base LZEBi

areaFloor Weighting Factor

areaFloor Weighting Factor

netEUI

netEUI netEUI

savings

1

1 ,

, , 100 ( )

%

where, i is the result for each individual model and N is the total number of model results. 

Using a set of models aligned with CBECS solves the problem of how to credibly assess 

the sector as a whole, but it also presents several challenges: (1) the number of CBECS 

buildings results in an extremely large number of simulations, (2) CBECS contains much less 

information on the sample buildings than is needed for building energy modeling, and (3) 

CBECS characterizes the existing building stock, not new construction—the target buildings for 

the ZEB program. The most severe technical challenge was how to deal with some 32,250 

simulations and the demand for computing resources and data management. These challenges 

were overcome by creating EnergyPlus input files based on a set of high-level building 

parameters and managing the simulation input and output in a database. To address the large 

computational needs, routines for dispatching and executing models on a 200 processor 

computer were developed. Finally, data mining methods were developed for reducing and 

analyzing results into manageable forms for reporting. 

Many technical problems were overcome by using a preprocessor that automates the 

creation of input files. Algorithms were developed to implement rules that define exactly how 

each building would be modeled from a set of high-level parameters. These rules included 

thermal zoning, HVAC system configuration and operation, overhang creation, and the use of 

multipliers to reduce simulation execution time for large, complex buildings. 

Basing the set of models on the 1999 CBECS provided a set of data that is limited 

compared to the detailed descriptions required for simulation. In addition, the assessment 

focused on the potential for new construction. Applying the current ASHRAE Standard 90.1-

2004 (ASHRAE 2004) enabled much of the detail on envelopes and equipment to be defined. 

This required developing large sets of data and algorithms for automatically applying Standard 

90.1-2004 to any commercial building. We also wanted to capture much of the variability of 

buildings, so we used probabilistic assignments (applying the central limit theorem) to create 

3
many details such as distribution of plug and process electrical loads, orientation and aspect 

ratio, and infiltration. Because exact locations are masked in the CBECS data, we developed 

algorithms based on degree-day information to assign locations to each building. Finally, the 

CBECS statistical model for existing stock (building type, floor area, number of floors, 

geographical location, weights etc.) was used as a proxy for a statistical model of the buildings 

being built in 2005 and beyond. 

Scenarios 

NREL ran EnergyPlus models for each of 5,375 prototypes under six scenarios: 

1. Base produced reference baseline results by applying Standard 90.1-2004 to define 

characteristics that affect energy performance. This is the same as rebuilding the entire 

commercial building stock to current energy standards.

2. Base with PV examined the impact of applying PV to Base. The systems applied 10% 

efficient PV panels with an area equal to 50% of the total roof area for every building. 

3. LZEB 2005 (Low-/Zero-Energy Building) examined what can be achieved when an 

aggressive package of currently available technologies and practices is applied. Each 

building was reoriented and elongated along an east-west axis for good daylighting and 

passive solar design. Exterior fixed overhangs were added to south-facing glazing. 

Tubular daylighting devices were added to core zones. The facade was modeled with 

superinsulation and superwindows. The HVAC system was changed to a centralized, 

chilled-water-based variable air volume system with economizer and heat recovery 

ventilation (HRV) on the outside air system. Lighting power density (LPD) was reduced 

17% from Standard 90.1-2004 by assuming the use of super T8 lighting (Sachs et al. 2004). 

The coefficient of performance (COP) of all chillers was set at 6.0. Gas heating efficiency 

was raised from 80% in the baseline models to 95% by assuming the use of condensing 

boilers. 

4. LZEB 2025 predicted the energy savings with all the same measures as the LZEB 2005 

scenario with higher component performances. This could reflect reasonable outcomes 

after 20 years of R&D. This scenario includes a doubling of the efficiency in rooftop PV 

panels and a slight improvement in inverter efficiency. LPD levels were reduced by 50% 

from Standard 90.1-2004 (DOE 2005). Chiller COP increased from 6.0 to 6.5, and heating 

efficiency increased from 95% to 97%. Fan static pressure decreased slightly, and minor 

improvements in HVAC systems are forecast. 

5. LZEB 2025 LPD75 modeled an optimistic level of success in the development of 

improved lighting sources such as solid-state lighting. It is identical to the LZEB 2025

scenario except that the design LPD is reduced by 75% from Standard 90.1-2004. This is 

an improvement over the LZEB 2025 scenario, which modeled an LPD reduction of 50%, 

which includes the impact of solid state lighting devices at 160 lumens/watt. The 75% 

reduction level was developed from the efficacy projections of 199 lumens/watt for 

laboratory solid-state devices by 2025 and assumes that such devices and other 

technologies could further reduce lighting energy use. 

6. LZEB 2025 PlugProcess25 modeled the reduction in energy use by appliances and all 

types of electrical equipment, collectively referred to as plug and process loads. Plug and 

process power densities were reduced by 25% from the LZEB 2025 models and all other 

4
scenarios. The intent is to model how the technical potential for ZEB might be affected by 

improvements in the efficiency of appliances and devices that use electricity inside 

commercial buildings (computers, copiers, cash registers, refrigerators, elevators, etc.). 

Results and Discussion 

The assessment study produced new data from simulation on the technical potential for 

ZEB technologies and practices to reduce the impact of commercial buildings on the U.S. energy 

system. The study developed quantitative estimates to answer this question: How low can you 

go? 

ZEB Goal and Percent Savings for Sector as a Whole 

Figure 1 shows the percentage of the commercial sector that can meet the ZEB goal 

under the five scenarios, in terms of both overall floor area and overall number of buildings. The 

ZEB goal was found to be achievable for portions of this sector—with 2005 technologies and 

practices, 22% of commercial buildings could reach net zero. Projections for technology 

improvements by 2025 increase this percentage to 64%. Calculated according to floor area, 

rather than by number of buildings, the percentages that can reach the ZEB goal are 23% for 

2005 and 53% for 2025. 

Figure 2 shows the potential percent savings in site energy for the sector as a whole. 

These results are presented in terms of net savings (which includes PV power production) and 

total end use savings (which includes only changes in efficiency). 

Figure 1. Percentage of U.S. Commercial Sector that Can 

Reach the ZEB Goal for Various Scenarios 

5

23

53

58 59

7

64

69 70

22

0

10

20

30

40

50

60

70

80

90

100

2. Base w/PV

3. LZEB 20054. LZEB 20255. LZEB 2025

LPD75

6. LZEB 2025

PlugProcess25

Percent able to reach ZEB goal 

Floor area

# of buildings

5
Figure 2. Percent Savings in Site Energy for U.S. Commercial Sector for 

Various Scenarios (100% represents ZEB) 

44

82

141 144

39

47 52 54

137

0

0

20

40

60

80

100

120

140

2. Base w/PV

3. LZEB 20054. LZEB 20255. LZEB 2025

LPD75

6. LZEB 2025

PlugProcess25

Percent savings in site energy 

Net (with PV)

Total (consumption)

The Base with PV scenario examined what can be achieved by adding only PV to cover 

50% of the roof area of each baseline-building model. The results show that 5% of the 

commercial floor area could reach the ZEB goal and that, for the sector as a whole, 44% of the 

site energy use could be offset with PV power. 

The LZEB 2005 scenario examined what can be achieved if an aggressive package of 

current technologies and practices to improve energy efficiency were also applied. This scenario 

showed that the amount of floor area that could reach ZEB reaches 23% and, for the sector as a 

whole, 82% of site energy could be saved. 

The LZEB 2025 scenario reflected two main performance differences—a doubling of the 

output available from rooftop PV panels and a 50% reduction in LPD. Under this scenario, 53% 

of the commercial floor area could achieve net zero and, for the sector as a whole, 137% of the 

site energy could be saved or 37% more energy could be produced than consumed by all the 

buildings in the sector. 

The LZEB 2025 LPD75 scenario showed an additional 25% reduction in LPD compared 

to the LZEB 2025 scenario (for a 75% reduction compared to Standard 90.1-2004). Under this 

scenario, 58% of the commercial floor area could achieve net zero and, for the sector as a whole, 

141% of the site energy could be saved. 

The LZEB 2025 PlugProcess25 scenario also showed a 25% reduction in plug and 

process power density compared to the LZEB 2025 scenario. Under this scenario, 58% of the 

commercial floor area could achieve net zero and, for the sector as a whole, 144% of the net site 

energy could be saved. 

The results of the Base with PV scenario show that efficiency improvements make the 

ZEB goal much more attainable. Adding rooftop PV systems to baseline buildings could allow 

5% of commercial floor area, and 7% of commercial buildings, to reach ZEB. But when 

efficiency measures are also added, these numbers increase: 4.1 times more by floor area, and 

3.2 times more by number of buildings, can reach ZEB than could with only PV. From an 

6
energy savings point of view, the 2005 vintage PV systems can reduce site energy use by 44%, 

on average; efficiency improvements can reduce site energy use by 39% for the LZEB 2005

scenario and 47%−54% for the LZEB 2025 scenarios. This indicates that the amount of energy 

that can be saved by efficiency measures is comparable to the amount that can be generated by 

rooftop PV panels and that pursuing both is important for reaching the ZEB goal. 

Analysis of the LZEB 2025 and LZEB 2025 LPD75 scenarios showed that the lighting 

system improvement saved 1.70 kBtu/ft2

·yr in lighting energy use. However, this improvement 

leads to a reduction in the total site energy use intensity of 2.11 kBtu/ft2·yr. This shows that (in 

the ZEB context) the added HVAC savings is 24% of the lighting energy savings, for the sector 

as a whole. Similarly, the LZEB 2025 PlugProcess25 scenario showed an average added 

benefit of 18%. (This means that reducing lighting or plug energy use by one unit will, on 

average, reduce whole-building site energy use by 1.24 and 1.18 units, respectively, because of 

the indirect effects on HVAC system energy use.) 

ZEB Goal by Geography 

The results can also be analyzed for geographic variation at the climate zone and census 

division levels. 

Standard 90.1-2004 uses a climate classification system with eight major zones. Results 

were sorted and weighted among all the buildings in each climate zone. Table 1 shows the 

percentage of floor area that can reach the ZEB goal for the climate zones and selected LZEB 

scenarios. Figure 3 shows the distribution of the climate zones. No buildings were assigned to 

climate zone 8 (because this applies only to portions of Alaska with sparse populations) and 

relatively few buildings are in climate zones 1 and 7. Climate zones 1, 2, and 3 show the best 

prospects for achieving the ZEB goal. 

Table 1. Percentage of Floor Area Able to Reach ZEB by Climate Zone 

Standard 

90.1-2004 

Climate 

Zone 

2. Base with 

PV 

3. LZEB 

2005 

4. LZEB 

2025 

5. LZEB 

2025 LPD75 

6. LZEB 

2025 

PlugProcess 

25 

All 5 23 53 58 59 

1 16 40 61 62 65 

2 12 38 73 76 77 

3 10 36 64 68 72 

4 3 16 44 51 51 

5 1 13 43 48 48 

6 0 12 45 54 50 

7 0 0 19 19 19 

7
Figure 3. Map of ASHRAE 90.1-2004 Climate Zones 

Source: www.energycodes.gov/implement/pdfs/color_map_climate_zones_Mar03.pdf 

The 1999 CBECS public use statistical data distinguish geography by the nine census 

divisions defined by the U.S. Department of Commerce (see Figure 4). Results were sorted and 

weighted among all the buildings in each census division. Table 2 shows the percentage of floor 

area that can reach the ZEB goal for the census divisions and selected LZEB scenarios. The 

results show less dependence than on climate. Prospects for reaching the ZEB goal are lower in 

the Midwest and Northeast regions. 

8
Figure 4. U.S. Census Bureau Divisions 

 

Table 2. Percentage of Floor Area Able to Reach ZEB by Census Division 

U.S. Census Division 2. Base with 

PV 

3. LZEB 

2005 

4. LZEB 

2025 

5. LZEB 

2025 LPD75 

6. LZEB 

2025 

PlugProcess

25 

All 5 23 53 58 59 

1 New England 0 5 34 40 39 

2 Middle Atlantic 1 8 34 39 39 

3 East North Central 1 17 45 52 51 

4 West North Central 2 14 48 55 54 

5 South Atlantic 9 31 61 63 65 

6 East South Central 8 29 66 74 76 

7 West South Central 10 33 67 71 72 

8 Mountain 10 32 62 65 67 

9 Pacific 8 29 56 61 63 

ZEB Goal and Energy Savings Potential by Subsector 

The results can also be analyzed by subsector, also called the principal building activity. 

The two basic criteria evaluated here are (1) the ease with which the ZEB goal can be met and 

(2) the sector-wide energy savings that could be achieved through ZEB technologies and 

practices. Figure 5 plots results by subsector for the portion of floor area in the commercial 

sector that could reach the ZEB goal under the LZEB 2005 and LZEB 2025 scenarios. Figure 6 

plots the results for the aggregated net site energy savings if these two scenarios were applied to 

every commercial building in the country. 

9
The relative potential of all subsectors can be examined by studying these figures. 

Offices have historically received the most research attention because they constitute the largest 

subsector. However, these results show that nonrefrigerated warehouses constitute an important 

subsector because they are the most likely to reach the ZEB goal and offer the highest total 

savings opportunity. 

Figure 5. Percentage of Floor Area that Can Reach ZEB Goal by Subsector 

0

10

20

30

40

50

60

70

80

90

100

All

Warehouse

(nonrefrigerated)

Office/professional

Education

Retail (excluding

mall)

Public

assembly

Strip

shopping

mall

Service

Religious

worship

Lodging

Food

Service

Health

Care Inpatient

Enclosed

mall

Public

order

and

safety

Food

sales

Health

care

(outpatient)

Vacant

Other

Skilled

nursing

Laboratory

Subsector

Percent of floor area able to reach ZEB goal

3. LZEB 2005

4. LZEB 2025

10
Figure 6. Aggregated Potential Net Site Energy Savings from 

ZEB Technologies and Practices by Subsector 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Warehouse

(nonrefrigerated)

Office/professional

Education

Retail (excluding

mall)

Public

assembly

Strip

shopping

mall

Service

Religious

worship

Lodging

Food

service

Health

care

(inpatient)

Enclosed

mall

Public

order

and

safety

Food

sales

Health

care

(outpatient)

Vacant

Other

Skilled

nursing

Laboratory

Subsector

Potential aggregate net site 

energy savings (quads)

3. LZEB 2005

4. LZEB 2025

Conclusions 

Analyses conducted to date have led to the following conclusions and subsector priority 

recommendations. 

The ZEB goal is technically achievable for significant portions of the commercial sector. 

This suggests that a ZEB goal is feasible and this goal can be used to direct research and other 

activities. 

Efficiency measures are important for reaching the ZEB goal. The amount of energy that 

can be saved by efficiency improvements is comparable to the amount that can be generated by 

current rooftop PV panels. 

A targeting strategy for selecting portions of the sector on which to focus should be 

developed based on two priority criteria: (1) how easily the ZEB goal can be met and (2) how 

much sector energy use can be reduced. The warehousing subsector offers the best opportunity 

for successfully meeting the ZEB goal because warehouses are often single-story buildings with 

low plug and process loads. Warehouses also represent the greatest opportunity for reducing 

energy use in aggregate. Office and professional buildings, educational, and retail buildings are 

the next most significant subsectors in terms of the potential for aggregated savings. 

11
References 

AEO. (2006). Annual Energy Outlook 2006. Washington, DC: EIA. Available from 

http://www.eia.doe.gov/oiaf/aeo. 

ASHRAE. (2004). ANSI/ASHRAE/IESNA Standard 90.1-2004: Energy Standard for 

Buildings Except Low-Rise Residential Buildings. Atlanta, GA: ASHRAE. 

Briggs, R.S., D.B. Crawley, and J.S. Schliesing. (1992). Energy Requirements for Office 

Buildings, Volume 1, Existing Buildings. GRI-90/0236.1, February. Chicago: Gas Research 

Institute (GRI). 

Briggs, R.S., D.B. Crawley, and D.B. Belzer. (1987). Analyses and Categorization of the 

Office Building Stock. GRI-87/0244, October. Chicago: GRI. 

Crawley, D.B. and J.S. Schliesing. (1992). Energy Requirements for Office Buildings, Volume 

2, Recent and Future Buildings. GRI-90/0236.2, March. Chicago: GRI. 

Crawley, D.B., L.K. Lawrie, F.C. Winkelmann, W.F. Buhl, Y.J. Huang, C.O. Pedersen, R.K. 

Strand, R.J. Liesen, D.E. Fisher, M.J. Witte, and J. Glazer. (2001). “EnergyPlus: Creating a 

New-Generation Building Energy Simulation Program.” Energy and Buildings 33: 319–

331. Amsterdam: Elsevier Science. 

DOE. (2005). Building Technologies Program Research, Development, Regulatory and Market 

Introduction Plan: Planned Activities for 2006-2011. Washington DC: DOE. Revised 

second generation draft, August 1, 2005. 

EIA. (2002). 1999 Commercial Buildings Energy Consumption Survey. Washington, DC: EIA. 

Available from www.eia.doe.gov/emeu/cbecs/1999publicuse/99microdat.html. 

Huang, J. and E. Franconi. (1999). Commercial Heating and Cooling Loads Component 

Analysis. Berkeley, CA: Lawrence Berkeley National Laboratory. 

Sachs, H., S. Nadel, J. Thorne Amann, M. Tuazon, E. Mendelsohn, L. Rainer, G. Todesco, D. 

Shipley, and M. Adelaar. (2004). Emerging Energy-Saving Technologies and Practices for 

the Building Sector as of 2004. Washington, DC: American Council for an Energy-Efficient 

Economy. 

12
REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

collection of information, including suggestions for reducing the burden, to Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents 

should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a 

currently valid OMB control number. 

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE (DD-MM-YYYY)

June 2006 

2. REPORT TYPE

Conference Paper 

3. DATES COVERED (From - To)

 

5a. CONTRACT NUMBER

DE-AC36-99-GO10337 

5b. GRANT NUMBER

4. TITLE AND SUBTITLE

Assessment of the Technical Potential for Achieving Zero-Energy 

Commercial Buildings: Preprint 

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

NREL/CP-550-39830 

5e. TASK NUMBER

BEC61002 

6. AUTHOR(S)

B. Griffith, P. Torcellini, N. Long, D. Crawley, and J. Ryan 

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Renewable Energy Laboratory 

1617 Cole Blvd. 

Golden, CO 80401-3393 

8. PERFORMING ORGANIZATION 

REPORT NUMBER

NREL/CP-550-39830 

10. SPONSOR/MONITOR'S ACRONYM(S)

NREL 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

11. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

12. DISTRIBUTION AVAILABILITY STATEMENT

National Technical Information Service 

U.S. Department of Commerce 

5285 Port Royal Road 

Springfield, VA 22161 

13. SUPPLEMENTARY NOTES

14. ABSTRACT (Maximum 200 Words)

The U.S. Department of Energy's Building Technologies Program has adopted the goal of making zero-energy 

commercial buildings (ZEBs) marketable by 2025. The National Renewable Energy Laboratory conducted an 

assessment of the entire commercial sector to evaluate the technical potential for meeting this goal with technology 

available in 2005 and projected forward to possible technology improvements for 2025. The analysis looked at the 

technical feasibility of ZEBs, limitations in market penetration and utility grid structures notwithstanding. 

15. SUBJECT TERMS

zeb; zero energy building; commercial building 

16. SECURITY CLASSIFICATION OF: 19a. NAME OF RESPONSIBLE PERSON 

a. REPORT 

Unclassified 

b. ABSTRACT 

Unclassified

c. THIS PAGE 

Unclassified

17. LIMITATION 

OF ABSTRACT

UL 

18. NUMBER 

OF PAGES 

19b. TELEPONE NUMBER (Include area code)

Standard Form 298 (Rev. 8/98) 

Prescribed by ANSI Std. Z39.18