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“Green” Building Rating Is No Guarantee of Energy Efficiency, Expert Says
David M. Hart
A privately administered program to certify buildings as “green” has become very popular, but a good rating by the program does not guarantee that a building is energy efficient, a policy expert told a recent AAAS seminar.
David M. Hart, director of the Center for Science and Technology Policy at George Mason University, has studied the history of the Leadership in Energy and Environmental Design (LEED) program, which awards ratings from “certified” to “platinum” for commercial buildings, schools and other structures that meet certain criteria such as innovation and design, sustainable use of materials and resources, indoor environmental quality and energy efficiency.
Research tracking building performance has shown that even buildings achieving “gold” or “platinum” ratings may be able to do so while lagging in their overall energy efficiency, Hart said. The building sector accounts for 39% or more of total energy consumption in the United States, 71% of electricity consumption, and 36% of all heat-trapping greenhouse gas emissions, Hart said, citing a U.S. Department of Energy survey.
If the nation wants to substantially reduce those emissions, he said, buildings will need to be more energy efficient. The LEED program allows tradeoffs that don't necessarily favor energy efficiency, Hart said, even though it has become synonymous in the United States with “green buildings.” He argued that the benefits of the LEED program, while worthwhile, should not be overstated. He called for a stronger government role in tracking energy use by buildings and in setting national standards for building codes.
“We're not going to get to climate-change nirvana strictly with non-government activity” in the building sector, Hart said. He spoke at a 5 November seminar sponsored by the AAAS Archives and the Chemical Heritage Foundation's Center for Contemporary History and Policy.
There is no question about the popularity of the LEED program, which is administered by the nonprofit United States Green Building Council. Through September 2009, a total of 25,611 buildings had been registered by building owners seeking eventual LEED certification. Through September, 3,855 of those registered buildings had won certification.
The AAAS headquarters building at 12th Street & New York Avenue NW in Washington, D.C.
The AAAS headquarters building in Washington, D.C., received gold-level certification for existing buildings through the LEED program in July 2009. Since 2008, operations at AAAS have released 1518 fewer tons of atmospheric carbon dioxide per year, compared to the industry standard for a similar building. Through an arrangement with the Pepco electric power company, AAAS also has arranged to meet 50% of its energy needs based on renewable sources such as wind energy.
Under the rating system for new construction under which most of the buildings seeking LEED certification have been registered, owners can receive up to a total of 69 points by meeting specific criteria in six categories: sustainable site; water efficiency; energy and atmosphere; materials and resources; indoor environmental quality; and innovation and design. There are four levels of attainment: Certified (26-32 points); Silver (33-38 points); Gold (39-51 points); and Platinum (52-69 points).
In principle, a project could win a platinum rating with 52 points and not receive any of them in the “energy and atmosphere” category. In practice, according to a LEED-accredited architect interviewed by Hart, it is difficult to reach a Silver certification or beyond without pursuing energy and atmosphere credits.
The Green Building Council has put forward ambitious goals for LEED, according to Hart. They would like to certify 100,000 buildings by the end of 2010, or 25 times as many as are now certified.
But even approaching such levels will depend critically on whether building owners can make a business case for pursuing a LEED certification, Hart said. So far, that has been hard to do. An April 2008 study by researchers at the University of California, Berkeley, found that LEED buildings did not command higher resale values than their non-certified counterparts.
The Berkeley study contained stronger findings for buildings that won a federal “Energy Star” rating, denoting an energy efficiency performance in the 75th percentile or better for comparable buildings (the AAAS building is an Energy Star recipient). Energy Star buildings earned higher resale values and rents, according to the study. If LEED buildings were to emphasize higher energy efficiencies, Hart said, they also might be able to make a better business case.
Still, Hart acknowledged that variations in energy efficiency are inherent in the LEED system. As he wrote in an MIT Industrial Performance Center working paper on the system: “LEED's designers sought to create a system in which 'green building' could mean different things to different people in different places. Building on a 'brownfield' site in an older industrial region or conserving water in a desert environment, for instance, may take precedence over saving energy in these locations.” Hart added, “LEED is a much bigger program than it would have been if it had used a rigid checklist instead of a menu of alternatives. Awareness of 'green building' is much broader, too, penetrating the mainstream of industry and even public consciousness to an unprecedented degree.”
The prerequisite for energy efficiency, which is required for all certified buildings, has also been toughened in the latest version of the LEED rating system released this year, Hart said. In the 110-point rating scale, a building must compete for up to 24 points for energy efficiency, compared to the 12 points in the earlier 69-point rating scale. It becomes more difficult for a building to win enough points for certification without getting some of them for energy efficiency.
Institutions that registered for LEED consideration under the previous system will be able to win certification under that rating scale, even if building construction is not completed by this year, Hart said. Also, owners of buildings that have won certification under earlier rating systems are not required to re-certify under the updated rating system or to satisfy performance requirements under the LEED program for existing buildings.
Hart is encouraged, nonetheless, by the greater emphasis on energy efficiency in the latest LEED rating system. He noted that the LEED program managers must walk a bit of a line as they place more emphasis on energy efficiency. Moving too aggressively could prompt some building owners to simply abandon their efforts at LEED certification.
Hart also noted that the LEED program must operate within a complex, fragmented U.S. building system in which private organizations such as the American Society of Heating, Refrigerating, and Air-Conditioning Engineers develop model building codes and standards, local and state governments enact energy and building codes, and federal agencies such as Department of Energy and the Environmental Protection Agency certify model codes.
“In the end, it seems to me the private sector alone just can't do this,” Hart said, referring to the push for more energy efficient buildings. LEED should continue to “really be a mobilizing force for people who want to be 'green,' ” he said, “educating the community, educating the architects, educating engineers.”
There remains a need for a national effort in which government can play a role, he said, including requiring disclosure of energy use and performance by buildings and requiring adoption of the latest engineering standards.
24 November 2009