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Contract No. DE-AC36-08GO28308

Results and Lessons Learned 

From the DOE Commercial 

Building Partnerships

Preprint

Adam Hirsch, Michael Deru, Rois Langner, 

Greg Stark, Ian Doebber, Jennifer Scheib, 

Michael Sheppy, Eric Bonnema, Shanti Pless, 

Bill Livingood, and Paul Torcellini

Presented at the 2014 ACEEE Summer Study on Energy Efficiency 

in Buildings

Pacific Grove, California

August 17–22, 2014

Conference Paper

NREL/CP-5500-61525

September 2014
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Results and Lessons Learned From the 

DOE Commercial Building Partnerships

Adam Hirsch, Michael Deru, Rois Langner, Greg Stark, Ian Doebber, Jennifer Scheib, 

Michael Sheppy, Eric Bonnema, Shanti Pless, Bill Livingood, Paul Torcellini, 

National Renewable Energy Laboratory

ABSTRACT

Over the course of 5 years, the National Renewable Energy Laboratory worked with 

commercial building owners and their design teams in the U.S. Department of Energy 

Commercial Building Partnerships (CBP) to cut energy consumption by 50% in new 

construction (versus code) and by 30% in existing buildings for a selected set of pilot projects. 

The objective was to identify strategies that could be replicated across their building portfolios. 

A number of building types were addressed, including supermarket, retail merchandise, 

combination big box (general merchandise and food sales), high-rise office space, and 

warehouse. The pilot projects began in pre-design and included a year of post-construction 

measurement data to evaluate performance. This paper describes the application of the LowEnergy Building Design Process (LEBDP) in the pilot projects, gives an overview of the results, 

and provides lessons learned to inform future efforts of this type. Although the pilot projects did 

not all reach the aggressive CBP energy saving goals, we concluded that the LEBPD could be 

deployed successfully with large portfolio owners in the private sector. Several ingredients, 

including owner commitment and a team focus on the energy goal from pre-design through 

occupancy, were necessary for success. Short simple payback requirements, large plug and 

process loads, and concern about changing the look and feel of retail spaces posed the biggest 

challenges to reaching the energy goals.

Introduction

The U.S. Department of Energy (DOE) launched the “Commercial Building National 

Accounts Partnerships” (later changed to the Commercial Building Partnerships or CBP) in 2009 

to increase the speed and scale of energy efficiency improvements in U.S. commercial buildings. 

CBP gave large commercial building portfolio owners and their design teams tools and processes 

to help reach ambitious energy saving targets in existing building retrofit (RF) and new 

construction (NC) projects, and demonstrated the performance of energy-saving strategies in real 

projects to promote replication. The building owners had the final say about which strategies 

would be incorporated, subject to internal economic, branding, and operational criteria. DOE 

documented these decision points to help improve market penetration of successful energy 

efficiency strategies.

DOE supported efficiency in two commercial delivery models: 1) “prototypical” 

buildings and 2) leased office spaces. In the first model, building owners or operators create a 

“prototypical” set of building plans that is used to generate many buildings, tailoring them to 

reflect variability in climate and building codes. As a result, generations of existing buildings are 

similar, so that successful retrofit strategies can be applied to multiple existing buildings, and 

improvements in energy performance can be easily replicated in all NC. In the second model, 
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owners or managers of multiple office buildings can apply successful strategies across many 

large buildings in their portfolios, each of which is subdivided into office spaces that are 

customized to the tenants’ needs. The CBP objectives were to identify processes and strategies 

that yielded 30% whole-building site energy savings for RF, versus a minimally compliant 

ASHRAE 90.1 baseline or versus pre-RF energy use and 50% site energy savings versus 

ASHRAE 90.1 for NC and to establish a firm business case that would justify replication across 

the Partners’ portfolios. 

National Renewable Energy Laboratory (NREL) researchers were involved with nine 

CBP projects that completed the entire program, including design, construction, and postoccupancy evaluation. This group included six RF and three NC projects, listed in Table 1. The 

project teams also included Partner representatives with expertise in the building design and 

procurement process and in building subsystems, and private sector experts in low-energy 

design, energy modeling, commissioning, and energy monitoring. Pacific Northwest National 

Laboratory and Lawrence Berkeley National Laboratory participated on similar CBP projects. 

The number of projects was initially higher, but decreased for several reasons, including the 

disruption to capital availability, business planning, and construction schedules caused by the 

2008-2009 recession. All the Partner companies are members of the DOE Better Buildings 

Alliance1

 and several (Best Buy, Kohl’s, Prologis, Walmart, and Whole Foods Market) are 

Better Buildings Challenge2 participants.

Table 1. Overview of NREL CBP Projects 

Partner Building Type

Project 

Type Climate Zone

Floor 

Area (ft2)

Date 

Construction 

Completed

Alliance for a 

Sustainable Colorado

Office 

Building RF 5B, cool and dry 38,500 May 2014

Best Buy General 

Merchandise NC 5B, cool and dry 30,500 March 2011

Bryan Cave-HRO Office

Building RF 5B, cool and dry 24,510 October 2010

Kohl’s General 

Merchandise RF 5A, cool and humid 87,000 November 2012

Prologis Warehouse RF 3A, warm and 

humid 800,000 October 2010

Target Combination 

Big Box RF 5B, cool and dry 173,000 November 2011

Target Combination 

Big Box NC 6A, cold and humid 133,000 July 2012

Walmart Combination 

Big Box RF 5B, cool and dry 200,000 June 2013

Whole Foods Market Supermarket NC 4A, mixed humid 40,000 March 2011

 

1 http://www4.eere.energy.gov/alliance/node/9

2 http://www4.eere.energy.gov/challenge/home
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The Low-Energy Building Design Process

The projects followed the Low-Energy Building Design Process (LEBDP) developed at 

NREL (Torcellini, Hayter, and Judkoff 1999). LEBDP is a multistep, integrated approach to 

designing and operating buildings that relies heavily on quantitative models of a building’s 

energy use and occupant comfort throughout the design and construction processes. By taking 

advantage of passive design strategies, aggressively reducing internal loads to enable smaller 

(and therefore less expensive) building mechanical systems, and carefully tracking the impacts of 

all design decisions, energy consumption in new buildings can be reduced by 50-70% versus a 

minimally code-compliant equivalent building (Torcellini, Pless, and Crawley 2005; Torcellini, 

Pless, Deru, et al. 2006). The process as applied in CBP is outlined in Table 2 (Torcellini, 

Hayter, and Judkoff 1999). DOE funded the researchers to apply the LEBDP and document the 

results; DOE provided no money to the Partners for equipment and construction costs. 

Table 2. The Low-Energy Building Design Process 

Step Description Summary

1 Simulate a base case building 

model.

Base case is solar neutral (model building orientation rotated by 

90°-270° and the results averaged) and meets requirements of 

applicable energy-efficiency code such as ASHRAE Standard 

90.1.

2 Design team brainstorms 

solution to energy problems.

In many CBP projects, commonly used strategies such as 

daylighting were not acceptable within the Partner’s business 

model because the look and feel of the interior spaces would 

change significantly; in those cases the brainstorming focused 

on how to reduce internal loads, use waste heat, etc. to reach the 

energy target.

3 

Perform simulations on variants 

of the base case relating to 

solutions developed in step 2.

Energy impact of each design package is determined by 

comparing the energy with the original base-case building and 

to the other variants. 

4 Architectural team prepares 

preliminary set of drawings. Drawings based on the decisions made during step 3.

5 

Determine the HVAC system 

that is best suited to meet the 

predicted loads.

The HVAC system should work with the building envelope. 

Often, the HVAC system will be smaller than would be 

required in an energy-inefficient building.

6 Finalize plans and 

specifications.

Ensure the building is properly detailed to avoid questions or 

implementation errors during construction. Ensure that the 

specifications and controls sequencing are correct. 

7 

Rerun simulations before 

design changes are made during 

construction.

Unforeseen circumstances may result in design changes during 

construction. Verify that any changes made do not adversely 

affect the building’s energy performance and occupant comfort.

8 

Commission all equipment and 

controls. Educate building 

operators.

A building that is not properly commissioned will not meet the 

energy efficiency design goals. Building operators must 

understand how to properly operate the building to maximize its 

performance.

NREL researchers used Opt-E-Plus (Long, Hirsch, Lobato, et al. 2010) to perform the 

energy simulations for LEBPD step 3. Opt-E-Plus leveraged DOE’s supercomputing resources to 

run EnergyPlus (U.S. Department of Energy 2014) simulations for thousands of combinations of 
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energy efficiency measures (EEMs), eventually tracing out the strategies that could work 

together to reach the CBP energy performance goals at comparable—or even lower—lifecycle

costs compared to a baseline building. The optimization capabilities of Opt-E-Plus are being 

incorporated into OpenStudio (Long et al. 2013; Hale et al. 2014), a free suite of tools with the 

ability to run multiple EnergyPlus models on cloud computing resources that, while not free of 

charge, are publicly accessible. When applying the LEPBD process, optimization was a helpful 

tool, but not an essential component. Even when optimization is not an option, industry-standard 

energy modeling software should be used to analyze the energy impact of design decisions on 

the overall building energy budget. There was also an assumption that other building owners and 

designers without the resources to invest in energy modeling would deploy the EEM packages 

demonstrated in the CBP pilot projects, based on the examples provided by the Partners. 

The universe of EEMs explored during early design was drawn from the experience of 

the Partners, from the national laboratories, from private sector subject matter experts, and from 

earlier energy analyses performed to support the development of DOE Advanced Energy Design 

Guides for 50% energy savings in general merchandise stores and grocery stores (Hale, Leach, 

and Hirsch, 2009; Leach, Hale, and Hirsch, 2009). The combination of strategies found to reach 

the energy saving goal was shared with the Partners, who then screened the EEMs using their 

criteria for economic returns and potential impacts on operations, sales, and branding. The list of 

recommended EEMs was often screened one item at a time using a simple payback criterion of 

just 2-3 years, rather than looking at an entire package of EEMs using a time horizon more 

consistent with equipment lifetime. In some cases, this could be traced to a short building lease 

period, which led to uncertainty about whether an investment would be recouped in saved energy 

costs. In terms of operations, sales, and branding, sometimes EEMs were rejected because they 

changed the look and feel of a retail space or placed a perceived barrier in front of a customer 

(for example, putting doors on refrigerated display cases, turning off electronic merchandise on a 

sales floor, or changing lighting quality or intensity). In some cases, the Partner may have felt 

that more research or testing was needed before committing to a technology. 

Results

Table 3 shows results from the projects that ran to completion. Some projects used a 

90.1-2007 (rather than -2004) minimally compliant ASHRAE baseline because they started later 

than the others, in a second phase of CBP pilot projects. As a result, a full year of postoccupancy energy consumption data was not available for comparison to the baseline to evaluate 

energy savings. The completed projects fell into four categories: 

1. Expected to reach the CBP energy saving goal and reached the goal (Target RF, Kohl’s 

RF, Prologis RF, Walmart RF); 

2. Expected to reach the goal and did not perform as expected (Bryan Cave-HRO RF, 

Target NC); 

3. Not expected to reach the goal (Best Buy NC, Whole Foods Market NC); and, 

4. Completed too late to provide a full year of performance data for this paper (Alliance for 

a Sustainable Colorado RF). 
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Table 3. CBP Whole-Building Energy Results 

Project Baseline

Energy Use Intensity 

(kBtu/ft2·yr)

% Savings Versus 

Baseline

Expected Measured Expected Measured

Alliance for a 

Sustainable Colorado RF ASHRAE 90.1-2007 37 TBD 31 TBD

Best Buy NC ASHRAE 90.1-2004 68 71 25 22

Bryan Cave-HRO RF Pre-Retrofit 33 43 38 19

Kohl’s RF ASHRAE 90.1-2004 45 39 39 48

Prologis RF Pre-Retrofit 11 11 41 41

Target RF ASHRAE 90.1-2004 77 81 37 33

Target NC ASHRAE 90.1-2004 53 72 52 44

Walmart RF ASHRAE 90.1-2007 106 95 24 32

Whole Foods Market NC ASHRAE 90.1-2004 303 291 33 36

Target saved 33% versus ASHRAE 90.1-2004 in its RF project (28% versus pre-RF). It 

subsequently worked with the researchers to simulate energy savings of the EEMs used in the 

project for other climate regions and rolled out the EEM package to more than a dozen existing 

stores in the year following the RF. Kohl’s halved the energy used to light its sales floor by 

replacing existing three-lamp T8 fluorescent fixtures with light-emitting diode (LED) fixtures, on 

the way to reducing whole-building energy use by 48% versus ASHRAE 90.1-2004 (38% versus 

pre-RF) and is considering whether to use LED fixtures for ambient lighting more broadly. 

Prologis retrofitted nearly 1,000 metal halide high-intensity discharge fixtures with T-5HO 

fixtures to cut energy use by 41%. This last project, a lighting RF in an unconditioned 

warehouse, was somewhat more straightforward than the others and did not require intensive 

EnergyPlus modeling. Prologis is replicating this RF project across its portfolio of buildings. 

In the Bryan Cave-HRO law office RF, plug loads were higher than expected and 

retrofitted variable-speed air handling unit fans saved less energy than expected. In the Target 

NC project, plug loads and lighting used more energy than expected, and the main sales floor air 

handling unit was programmed to turn on earlier than it should have, leading to excess electricity 

and natural gas consumption. This error was corrected, cutting monthly winter gas consumption 

dramatically during the winter of 2013 versus 2012. 

The two projects that were not expected to reach the savings goals had high plug and 

process loads (PPLs) that could not be significantly reduced, leaving less scope for overall 

building energy savings. In the case of Best Buy, a substantial fraction of the store’s energy was 

consumed by products on display, which were required to remain on during the day. Whole 

Foods Market had extensive food preparation and a commercial refrigeration system. These are 

energy-intensive end uses that increased the challenge of achieving significant energy savings 

cost-effectively. The projects were still followed to completion because, although the companies 

were expected to make efforts to reach the energy goals, it was understood that they would do 

this within the constraints of their business models. Valuable lessons were learned from both 

projects and the EEMs used in CBP continue to be used in their buildings. 

Another important result of the pilot projects was the list of EEMs used by the Partners. 

Table 4 includes some notable technologies grouped by end use and project, representing a new 

business as usual. 
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Table 4. Prominent Energy Efficiency Measures 

End Use EEM Projects Featuring This EEM

Envelope 

Increase roof insulation R-value beyond 

code requirements Target (NC), Best Buy (NC)

Skylights for daylighting Best Buy (NC), Whole Foods (NC), 

Walmart (RF)

Lighting 

Photosensors and dimmable electric 

lighting sources to take advantage of 

daylighting.

Best Buy (NC), Whole Foods (NC), 

Walmart (RF)

Reduce sales floor lighting power density 

below 1.0 W/sf 

Target (NC, RF), Best Buy (NC), 

Kohl’s (RF), Whole Foods (NC), 

Walmart (RF)

Vacancy sensors in offices, stockrooms, 

walk-in coolers/freezers, and restrooms Target (NC), Walmart (RF)

LED accent lighting Target (NC, RF), Kohl’s (RF), 

Whole Foods (NC), Walmart (RF)

LED exterior lighting Walmart (RF)

LED ambient lighting to provide the same 

illuminance using less power

Kohl’s (RF), Alliance for a 

Sustainable Colorado (RF)

HVAC

Variable-speed HVAC supply fans Target (NC, RF), Kohl’s (RF), 

Bryan Cave-HRO (RF)

Widen temperature deadband set points Target (NC, RF)

Evaporatively cooled condensers Target (NC, RF), Walmart (RF)

Energy recovery ventilators Target (NC, RF)

Desiccant dehumidification Target (NC), Whole Foods (NC)

Performance-based indoor air quality 

compliance Target (NC, RF)

Demand controlled ventilation 

Best Buy (NC), Kohl’s (RF), 

Alliance for a Sustainable Colorado 

(RF)

Capture of medium temperature 

refrigeration system waste heat for 

ventilation pre-heating

Walmart (RF), Whole Foods (NC) 

Plug Loads 

Computers enter standby mode when not 

in use Target (NC, RF)

Checkout stands and registers have 

standby mode and turn off during 

unoccupied hours

Target (NC, RF)

Refrigeration

Doors on medium temperature refrigerated 

display cases Walmart (RF), Whole Foods (NC) 

Electronically commutated evaporator fan 

motors

Target (NC, RF), Walmart (RF), 

Supermarket (NC)

Floating control for saturated suction and 

saturated condensing temperatures Target (NC, RF)
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LED refrigerated display case lighting Target (NC, RF), Walmart (RF), 

Supermarket (NC)

Modulate anti-condensate heaters based 

on sales floor dew point

Target (NC, RF), Whole Foods 

(NC)

Variable-speed condenser fans Target (NC), Whole Foods (NC)

Install electronic expansion valves to 

lower minimum condensing temperature 

from 75°F to 55°F

Whole Foods (NC) 

Commercial 

Kitchen

Close-proximity hood controlled by 

temperature and particulates Target (NC), Whole Foods (NC) 

Install side panels on all exhaust hoods to 

lower flow rate while capturing all exhaust 

fumes

Whole Foods (NC) 

Lessons Learned

Several common lessons emerged from the projects that will help the Partners and other 

commercial building owners design and operate high-performance buildings. The most important 

general lesson learned was that the building owner and design team must stay focused on the 

energy target in all the stages from pre-design through post-occupancy monitoring and 

performance maintenance to achieve high energy performance. Ultimately, this focus depended 

on building owners who prioritized energy efficiency, were willing to stick to an energy goal, 

and were willing to rethink their building design and operation processes. 

Coordinating Deployment and Research

Deployment of successful technical solutions across building portfolios was a CBP 

priority from the start. Partners with large building portfolios and standardized building designs 

were chosen for participation so that the initial investment in pilot projects could be leveraged to 

achieve large savings when the solutions were applied broadly. Although many Partners 

confirmed that EEMs from the pilot projects would be included in broad RF efforts and in future 

prototypical designs, programs such as CBP would benefit from a follow-on phase in which the 

national laboratories stay engaged with the Partners to document replication and the long-term 

impact on the design process over time.

The research dimension focused on whether model predictions about operational energy 

use of the building were accurate at the subsystem level (lighting, HVAC, PPLs, and 

refrigeration). While mismatches between model predictions and measurements could be used to 

correct modeling assumptions and to identify building operational issues, discrepancies arose for 

one (or more) of three reasons: 

1. The submetered energy data were occasionally inaccurate. In most cases, NREL had 

control over the quality of the data coming from the projects; however, in some projects, 

when submetering was provided by a third-party contractor, sensor calibration and 

labeling issues were discovered by NREL after reviewing the data.

2. The energy modeling has inherent uncertainties. For example, the interactions between 

refrigeration and HVAC systems were complex and hard to capture accurately. Newer 
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technologies such as complex dehumidification systems were challenging to represent 

accurately in EnergyPlus. 

3. Some of the buildings operated outside their original design specifications, leading to 

excess energy use. It was not uncommon, even in new buildings, for lights to be left on at 

night, or HVAC set points to be overridden in unanticipated ways. Installed PPLs were 

different than those in design estimates, or the assumptions about those loads may have 

based on benchmarking measurements rather than a detailed model. Creating an accurate 

PPL model required creating an inventory of all equipment and understanding how that 

equipment would be used. 

Resolving these discrepancies required significant effort at the tail end of the projects, 

when performance data were available for analysis and when momentum behind the project may 

have diminished. The CBP projects showed that continued engagement and resources were 

required after the “completion” of the project to understand whether the original design-phase 

expectations for energy performance at the end-use level were realistic and whether the building 

was being operated in a way that maximized energy savings. Unless the building owner’s project 

requirements specified comparison of operational energy performance with energy model 

predictions in some sort of project closeout, the design team might move on to other projects 

after construction and initial commissioning and not achieve the expected energy savings. In 

some cases, energy-saving technologies proved to be “plug-and-play,” but in many cases work 

was still required to integrate them successfully.

Design Lessons

1. Energy goals motivate innovative thinking. In most cases, the energy-saving targets 

encouraged the Partners to consider strategies they had not tried before. In some cases the 

Partners decided these strategies were worth pursuing and that implementation challenges 

could be overcome; in other cases they decided that the strategies repaid too slowly 

through energy savings or would disrupt their customers’ shopping experiences. The 

iterative energy modeling approach from the LEBPD process gave Partners the energy 

cost savings information they needed to make the business case for pursuing new 

technologies. The integrated design perspective of the LEBPD process helped the 

Partners to search for ways to reach the energy goals while holding fast to their stringent 

economic criteria. 

2. A “bundled” approach to analyzing EEMs can increase savings. Many Partners 

selected EEMs on an “a la carte” basis, where the economic performance of each EEM 

was considered separately from the others and eliminated from consideration if the return 

on investment was considered unacceptable (often using a 2-3 year simple payback 

threshold). However, some Partners looked more broadly at the business case of multiple 

EEM “bundles.” In the best case, all the EEMs were considered together using an 

integrated approach. The business case included energy savings, utility incentives for 

efficient equipment, and HVAC first cost savings achieved by reducing internal gains. 

Within an EEM package, several EEMs with a quick payback can help make the 

economics of the entire package acceptable, increasing energy savings. In the 

performance evaluation phase of the project there was also a temptation to calculate the 

performance of each EEM in isolation instead of the energy savings of the integrated 

package at the whole-building level, in support of the “a la carte” approach.
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3. Standard baseline assumptions are needed for commercial refrigeration and kitchen 

systems. When the projects began, ASHRAE 90.1 did not address commercial 

refrigeration and kitchen equipment. Yet, the Partners took actions in these areas that 

resulted in energy savings versus their usual practices. This situation was problematic for 

supermarkets, where refrigeration consumed 30-50% of a store’s energy. To allow the 

Partners to take credit for refrigeration energy efficiency improvements, a baseline 

refrigeration system was defined to allow benchmarking of the low-energy designs, 

intended to represent a typical circa-2010 commercial refrigeration system. That baseline 

has since been updated to reflect recent regulations on refrigeration equipment energy 

consumption (Doebber et al., 2014). 

Operational Lessons

1. Commission early and comprehensively. Often a delay occurred between building 

handover and commissioning and then a further delay before the issues were addressed. 

In many cases, equipment or control problems were not discovered or fixed until several 

months had passed, leading to higher energy use (higher EUIs) than expected in the first 

year of operation (the period used for evaluating the pilot project performance). However, 

with continued engagement, many issues were corrected, such as the winter heating issue 

mentioned for the Target NC project, bringing the EUI closer in line with expectations. 

Commissioning best practices can be found in ASHRAE Guideline 0-2013, “The 

Commissioning Process,” which focuses on capturing the building owner’s project 

requirements in the design documents from the earliest project phases and establishing 

the criteria for documenting that these requirements have been met (ASHRAE 2013a). 

Refrigeration system-specific information can be found in the “Refrigeration 

Commissioning Guide for Commercial and Industrial Systems” (ASHRAE 2013b). Some 

commissioning issues can be subtle, requiring a detailed understanding of the design 

intent. For example, one Partner installed a complex dehumidification system with an 

active desiccant wheel. However, the unit was installed without the intended bypass so 

that even when dehumidification was not required, air had to pass through the wheel, 

incurring a fan energy penalty caused by the increased pressure drop. 

2. Compare expected energy consumption with measured use. The traditional 

commissioning process does not consider energy, per se, or include a comparison 

between measured and modeled energy use. However, comparing expected and measured 

energy use for subsystems and the whole building was an important clue to whether the 

building was operating as designed and therefore whether the money invested in energy 

efficiency was providing real savings. To provide useful information at the end-use level, 

the energy submetering system needed to be designed and commissioned along with the 

rest of the building, not added as an afterthought, at least at the level of aggregated 

building end uses of lighting, HVAC, PPLs, and refrigeration (National Science and 

Technology Council 2011). The final design energy model can be used as an operational 

energy model to provide expected energy use. 

3. Screen building data for operational problems. Two Partners (Target and Kohl’s) used 

information systems to automatically identify operational problems such as building 

lighting or HVAC systems being on at full power for multiple days. This automated alert 

system was standard practice for these Partners, not initiated as part of CBP. At the same 

time, close scrutiny is required to catch fault patterns that may not have been 
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programmed into the detection system. For some Partners who did not use this strategy, 

high performance lighting and HVAC systems were often undermined by operational 

patterns that fell outside design intent and should have been corrected. Defining a process 

to find and fix problems that result in wasted energy was important for maintaining 

energy savings, especially after the initial building acceptance period. 

General Lessons

1. Clearly establish project goals and team roles. CBP involved unique public-private 

collaboration between organizations with very different priorities. Therefore, good 

communication, a common understanding of roles and responsibilities, and a unified 

commitment the project goals were key elements of project success. It was also important 

that all stakeholders, including corporate branding and sales representatives were 

included on the project team. Because the project had a long duration, the team 

composition often shifted over time. It was crucial to orient new team members quickly 

about the project energy goals and how the LEBPD worked. 

2. Maintain a focus on performance goals. The project teams sometimes lost focus on 

energy performance after occupancy because of the pressing concerns of other 

commitments and new NC or RF projects. The project was considered “done” as long as 

building set points were satisfied, without considering whether the expected return on 

investment in efficiency was being captured. Best practices for keeping the project team 

focused on energy goals all the way from project initiation through building occupancy 

can be found in Pless et al. (2013). 

3. Different goals have their own strengths and weaknesses. Percent site energy EUI 

savings versus a minimally-code compliant baseline had the advantage of being a single 

number to focus the team’s efforts. The energy code requirements were also clearly 

documented, for example in the form of ASHRAE 90.1 Appendix G. However, in 

practice this metric presented some challenges. 

a. Time and resources were required to build the baseline model and ensure that it 

met the prescriptive code energy requirements. This investment might be a 

disincentive for design teams in the private sector. For end uses not directly 

addressed by the energy code, such as PPLs, either no savings could be claimed 

for those end uses or a workaround had to be engineered to represent baseline 

conditions. Code-based baselines were also of limited interest to private 

organizations interested in improving performance against the current 

performance of their buildings or those of their peers. Several of the Partners 

already exceeded the ASHRAE baseline in their business-as-usual prototypical 

designs and did not consider this performance as imposing additional costs on 

their design and construction process. Reaching the CBP goals may not have been 

the furthest they could have stretched. Typically, an additional energy model 

representing the Partner’s current building practices was created for the new 

construction projects, for the purpose of benchmarking the new design 

performance against business-as-usual for economic evaluation of EEMs. 

b. The definition of “minimally code compliant” shifts with subsequent versions of 

the energy code. Because of the time required to go through the entire design, 

construction, and performance verification process, relevant code for 
11

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

benchmarking can evolve significantly over the course of the project. It is 

challenging to know whether 50% energy savings versus ASHRAE 90.1-2004 

(typical of local ordinances when CBP started) is still “good” compared to 

ASHRAE 90.1-2010 or 90.1-2013 unless another baseline model is created. A 

benchmark that doesn’t change may facilitate comparison of performance over 

time. Net zero energy performance provides one example of a clear-cut and 

unchanging performance metric.

A whole-building EUI can also make it difficult to compare the performance of one 

building type to another. For example, in Table 3, the supermarket appears to be in an entirely 

different class of energy use compared to, for example, the combination big box stores, even 

though the big box stores may have similar refrigeration systems. The reason is that the 

combination big box stores also have a large dry-goods sales area (with lower power 

consumption) so that when the large process refrigeration load is normalized by floor area, it 

appears much lower. Additional metrics, such as kW/ton of refrigeration, or normalizing energy 

use by another quantify such as sales volume would shed additional light on the inherent 

efficiency of one store versus another. 

Conclusions

By demonstrating that significant energy savings were possible while the Partners’ 

investment criteria were being met and without radically changing their corporate look and feel, 

CBP set the stage for replicating the pilot project efforts throughout their portfolios and setting 

examples for their peers to emulate. The projects demonstrated that the LEBDP can work for 

owners of large building portfolios who are dedicated to generating economic returns for their 

investors and to being good environmental stewards. Time will tell whether they continue to use 

the LEBDP with their design teams and maintain energy goals without the participation of the 

national laboratories. At the same time, the projects highlighted a need for a consistent 

benchmark for refrigeration and commercial kitchen energy use and the importance of focusing 

on energy performance from pre-design through occupancy. Maintaining a consistent “look and 

feel” for retail spaces and avoiding impacts on customer’s shopping experiences led to a 

conservative approach to energy EEMs such as daylighting and putting doors on refrigerated 

display cases. Clear demonstrations of the non-energy benefits of these strategies; for example, 

warmer supermarket aisles and more natural lighting quality may help them gain broader 

acceptance. 

Acknowledgements

The authors would like to thank the DOE Office of Efficiency and Renewable Energy 

and Building Technologies Office, the representatives of the CBP Partner companies, and the 

subcontractors who provided subject matter expertise for CBP. The authors would also like to 

thank Target Corporation, Walmart, Best Buy, Kohl’s Corporation, Alliance for a Sustainable 

Colorado, Bryan Cave-HRO, Whole Foods Market, and Prologis, the Partners that worked with 

NREL during CBP.
12

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

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