What is in this article?:
- Tracking Energy Efficiency in Commercial Buildings
- An Explosion of Data
- There Can be Only One
The EIA prepares to start a new round of its federal energy use survey of commercial buildings
There Can be Only One
Since 1979, the U.S. Energy Information Administration’s (EIA) Office of Energy Consumption and Efficiency Statistics has been compiling and publishing the results of its national sample survey, the Commercial Buildings Energy Consumption Survey (CBECS), which it conducts every three to four years. The results provide the only national-level source of data on the characteristics and energy use of the existing stock of commercial buildings in the United States. “CBECS is meant to be a snapshot in time of what was going on in commercial buildings during the reference year of the survey,” says Joelle Michaels, CBECS survey manager. “It represents commercial building stock as a whole.”
The survey process includes an advance package of materials (including worksheets) that is provided to the building owner or operations contact a few days before the interview is conducted. The interview, usually conducted in-person by a professional interviewer using a computerized survey instrument programmed in-house by EIA using a survey processing language, covers many topics, including building size and use; ownership and occupancy; energy sources, uses, and equipment; and
energy consumption and cost. The average interview lasts around 30 minutes.
“There are questions about the building itself,” says Michaels. “Those set up general questions about the building, and then we get more technical and more energy related.”
The questions differ depending on building size, type, and use. “A huge hospital is going to have a much more complex interview than a corner store that basically is more residential in its systems,” says Michaels. “A small building will have different questions versus a huge building with multiple systems. It varies widely.”
In addition, the interviewer tries to get to the best source of information about the building and its energy use. “We contact the building owner, the building manager, the operations lead, or the energy engineer,” says Michaels. “The type of information we get varies a lot by the type of person, so we’re looking for the person who is knowledgeable about the energy use in the building. Ideally, if you have an operations and maintenance person, that’s your best respondent.”
If energy usage information is not available or if there are questions about the data provided, the building survey is followed up with an energy supplier survey. “If they can’t provide the information or if it seems incorrect, we have some edit checks built into our instrument just to make sure the figures seem reasonable,” says Michaels. “We ask them to sign an authorization form, and we’ll go to their energy supplier.”
Energy suppliers are consulted for about half of the CBECS buildings. Historically, the sample size totaled between 5,000 and 7,000 buildings. Unfortunately, due to budget issues, the database is missing the data from last two information-gathering cycles. In 2007, in an effort to save money, EIA contracted out the interview process. After reviewing the data, the office determined the CBECS 2007 data did not meet EIA standards for quality, credible energy information. As a result, EIA will not publish complete data tables from CBECS 2007 or release a public use file. “There was somewhat of an experimental approach used to update our frame for buildings — the list of buildings from which we will select buildings to interview — that were constructed,” says Michaels.
EIA expected to save 30% of the usual survey cost, which equated to a few million dollars. “We’ve learned that we cannot cut corners on this survey,” said Tom Leckey, director, Office of Consumption and Efficiency Statistics at EIA, in a press release accompanying the announcement that the results would not be published. “It delivered on the lower costs, but it did not deliver on the validity of the sample.”
Then, in 2011, the survey was suspended as a result of budgetary cuts by Congress, which cut EIA’s funding by 14%. Due to these setbacks, the latest available data dates back to 2003, forcing the programs that rely on it to date back almost a decade. For example, an office within EIA uses the data for its 30-year long-term energy use forecast. In addition, the U.S. Environmental Protection Agency’s (EPA) Energy Star uses the CBECS data as an essential input into its Target Finder program, a no-cost online tool that enables architects and building owners to set energy targets and receive an EPA energy performance score for projects during the design process. Projects that earn a score of 75 or higher are eligible for certification and can be submitted for the Energy Star Challenge. USGBC’s Building Performance Partnership (BPP) relies on CBECS data for the commercial sector, along with WegoWise for multifamily residential.
“There’s been a 10-year gap in the CBECS,” says Bloom. “Overall, business has become much more of an energy-intensive process, so companies are using more energy and, therefore, stand to benefit more from investments in energy-efficient technology. Now information technology (IT) uses so much more space in commercial buildings than it had in the past, and IT is obviously very energy intensive.”
There are alternatives to CBECS. California customers have access to the California End Use Survey (CEUS), which has benchmarked 2,700 buildings. Gridium benchmarks with both CBECS and CEUS for California customers. ASTM BEP offers a standardized process for benchmarking. The National Institute for Building Science (NIBS) has proposed a High-Performance Building Data Collection Initiative, which NBI supports, as a path forward for collecting and disseminating data. The Green Building Alliance — now in consort with the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) — has been working for several years to develop its Database for Analyzing Sustainable and High Performance Buildings (DASH), a publicly available collection of data about building operation, maintenance, and performance, especially for green, sustainable, and high-performance buildings. Additionally, owners of multiple buildings can perform internal benchmarking, or they can arrange to trade data with owners of other buildings.
However, EIA has resumed preparations to conduct the next CBECS, with plans to field the survey between April and September 2013, with the energy supplier survey following. “We’re finalizing our questionnaire right now and working on the sampling frame,” says Michaels. “So we’re doing all that right now in preparation to go into the field and do the survey in April. We’re deep into the development of the survey.”
The interviewers will collect data for reference year 2012. EIA expects to publish the first results of the survey in the first half of fiscal year 2014.
EIA will provide regular project status reports to the public throughout the course of the project. To safeguard the integrity of the data, EIA’s status reports for CBECS 2012 will report on risk mitigation strategies undertaken to assure the delivery of the data. “For 2012, we’re returning to more tried-and-true methods of updating the sampling frame that we are confident will provide accurate and reliable results,” says Michaels.
Yet, there will be some changes for 2012. The sample size will be increased by 150%, meaning the target number of buildings for 2012 is around 8,500 buildings. In addition, a subset of buildings will be re-interviewed/verified using energy audit techniques. Finally, some interviews will be conducted by telephone in order to locate more knowledgeable respondents.
On May 15, USGBC hosted the 2012 CBECS Stakeholder Meeting. About 20 participants attended in-person and another 40 or 50 participants virtually attended via webinar, representing a variety of industries — including government, trade associations, real estate, energy consultants, advocacy groups, architects, engineers, laboratories, and equipment manufacturers. EIA presented its planned changes to the 2012 CBECS questionnaire and took comments from the audience on each section. “We have very extensive meetings with our stakeholders and got a lot of input on changes we should make and new questions we should ask,” says Michaels. “So we are revising the questionnaire quite a bit to keep it relevant.”
Still, Michaels speculates that some gains in energy efficiency will prove to be offset by increased energy use in commercial buildings. “You’ll have existing buildings that aren’t part of these energy-efficient initiatives,” says Michaels. “So I’m not sure whether we’ll see dramatic results or not.”
According to Michaels, in addition to all the energy-saving policies and initiatives that have been implemented, there’s also a lot more energy use occurring in buildings. “There are a lot more computers,” she continues. “End-use has gotten more intensive at the same time as buildings have become more energy efficient, so those measures cancel each other out.”