EPA Committed to Keeping Energy Star on Track
More than 21 billion square feet of commercial building floor space, representing close to 30 percent of the market, has been benchmarked in the Energy Star Portfolio Manager tool. The Energy Star score has been a valuable tool to motivate energy-use reductions and to identify top performing buildings.
Recently, however, there have been problems with a little-known federal database that Energy Star uses. Despite those problems, the U.S. Environmental Protection Agency is confident that the Energy Star rating remains a valuable tool for building owners.
That federal database — referred to as CBECS (Commercial Building Energy Consumption Survey) — comes from a national survey administered by the Department of Energy's (DOE's) Energy Information Agency. The survey draws from a statistically valid sample of the universe of commercial and institutional buildings and provides important building and energy data.
Using CBECS, EPA made a startling discovery in the late 1990s: the gap between the country's best- and worst-performing buildings was greater than anyone had previously acknowledged — as large as tenfold. To help building owners understand how their buildings compare, EPA launched the Energy Star 1 to 100 scale in 1999 to provide feedback on where a building's energy use falls along this spectrum. That 1 to 100 scale is largely based on data from CBECS.
Unfortunately, DOE recently announced that results from the most recent survey (2007) would not be published because it had not yielded valid statistical estimates. At the same time, DOE reported that, as a result of lower funding levels, it would temporarily suspend work on the survey scheduled for this year (2011). That means CBECS data continues to be drawn from the 2003 survey.
Even with questions surrounding CBECS, Energy Star still offers relevant benchmarks. Here's why:
1. The 2003 CBECS survey still offers a solid benchmark. The rate at which new construction and retrofits replace building systems is slow. According to recent studies of actual energy use, new buildings can still perform more poorly than the CBECS 2003 average.
2. Each time EPA has analyzed the key drivers of energy use for offices, the major drivers were the same: workers, hours of operation, computers, size, and climate. This consistent result over 12 years suggests that the methodology underlying the Energy Star score, which is based on those drivers, remains sound.
3. Because the Energy Star score applies the same calculation to everyone, it remains a consistent means of placing all buildings on the same scale.
4. In addition to being an industrywide benchmark, the Energy Star score can also be used to track energy use of a building over time. Regardless of the age of the data on which the score is based, the actual number provides a uniform measure of how performance has changed.
5. While CBECS is used for many Energy Star scales, it is not the only data used by Energy Star. The scales for hospitals, senior care facilities, and data centers are all drawn from other surveys. EPA continues to work with industry to find other nationally representative data (or means of collecting data) to make Energy Star scales available for more building types.
6. As more buildings save energy, questions may be raised about whether it is becoming too easy to earn the Energy Star. If that becomes a concern, EPA could reset the minimum Energy Star score higher than 75.
For all these reasons, EPA is confident that Energy Star continues to serve the market effectively. However, if the CBECS 2011 survey is cancelled, EPA will examine data and track trends of buildings using the Portfolio Manager tool and other surveys to assess market conditions and evaluate alternatives. It is possible to generate alternative data sets that are nationally representative, and EPA is willing to explore this option to ensure that Energy Star remains a valuable energy management tool.
— Jean Lupinacci is chief, Energy Star commercial and industrial branch, U.S. Environmental Protection Agency. |