When it was dedicated in March 2008, the Jerry Yang & Akiko Yamazaki Environment and Energy Building (Y2E2) was hailed as a monumental achievement of energy efficiency in 21st century building. “Y2E2 is much more than a building,” Jeffrey Koseff, Director of the Woods Institute for the Environment, remarked at the time. “It is a symbol of what is possible.”
However, a report released in October 2009 by researchers at Stanford’s Center for Integrated Facility Engineering (CIFE) has called into question the level of efficiency of the structure. The CIFE researchers evaluated the first year performance of Y2E2 based on the building planners’ initial predictions and found that actual energy consumption was significantly higher than initially predicted during the building’s planning stages.
Specifically, the report contends that “actual [energy use] exceeded the initial prediction and design objective by about 65%.” Based on that evaluation, the CIFE researchers commented, “The data suggest that, even when good people try hard, energy performance comes nowhere near objective, and the objectives need to become much more stringent.”
When asked about the large gap between predicted and actual levels, Joseph Stagner, Executive Director of Stanford’s Sustainability and Energy Management department, explained, “The 65% figure compares what the original estimated energy use would have been at first building conceptual design stage, before substantial additional things were added to the building during the final design process such as a café.” Fahmida Ahmed from the Office of Sustainability added, “The occupancy of the building is far different than originally assumed by the designer – Y2E2 essentially became a 24/7 building.”
When such factors were included in revised standards, outcomes were significantly different. “[Y2E2 is] essentially performing as expected,” Stagner indicated. “The building is using about 40% less energy than a standard building of this type would.” The CIFE report more or less confirms this analysis, stating that “actual [energy use]… exceeded the revised objective by a little less than 5%.”
Such revised standards have become much more common in the “green building” industry. Scott Gould from the Office of Sustainability indicated, “A lot has changed in the industry since the original building models were created for Y2E2. ‘Exceedence’ models are now more common.”
However, according to the CIFE report, shortcomings in predicting energy use have still been widespread. “[The industry] needs fundamentally new methods to respond to requirements for efficiency, effectiveness and performance,” the CIFE researchers contend. “[Actual energy use] systematically and dramatically exceeds objectives.”
The report details a number of instances of failures to meet initial energy use objectives. At a sustainable building project in Malmö, Sweden, all twenty buildings constructed had observed amounts of energy use surpassing expected quantities. Likewise, a “highly publicized” building at Oberlin College in Ohio experienced measured energy use at a level two to three times higher than expected.
Based on such outcomes, an American Physical Society article, cited by the CIFE report, criticized such efficiency metrics as the U.S. Green Building Council’s LEED Green Building Rating System for focusing on “design simulations” rather than “building energy performance.” The article noted that improving projections should be a site for further research: “There has been very little work on validating whether projections of performance correspond to actual building performance; that is an area requiring further research.”
At Stanford, plans for more green buildings are full speed ahead. Ahmed said that her team will continue to improve its efforts to improve projections. She described a “building performance Dashboard system,” which will to help to measure energy use at an even more sophisticated level.
Joseph Stagner further affirmed Stanford’s commitment to sustainability. “We are moving very aggressively to design high performance energy efficient buildings,” he said. “Stanford remains committed to leading the way in efficient campus operations and sustainability.”