Washington, DC [RenewableEnergyAccess.com] More can be done to achieve the Department of Energy’s (DOE) goal to achieve marketable zero-energy buildings by 2025, concludes findings published in a recent study of low-energy, high-performance commercial buildings in the U.S. While the six buildings in the NREL study were found to save 25 to 70 percent lower energy consumption than allowed by code, that’s just not enough.The study, commissioned by DOE’s Building Technologies Program and conducted by the National Renewable Energy Laboratory (NREL), analyzed six buildings that represent the current generation of low-energy commercial structures. These buildings were designed to meet low-energy and sustainability goals by using innovative combinations of energy technologies such as daylighting, radiant heating, natural ventilation, photovoltaic systems, evaporative cooling, and passive solar strategies. “Commercial buildings account for 18 percent of total energy consumption in the United States, with lighting and heating being primary energy-consuming activities,” said David Rodgers, manager for the DOE’s Building Technologies Program. “With this study we’ve learned how well a sampling of today’s model low-energy buildings actually did on meeting their original energy goals. Using this ‘baseline,’ we can now supply a set of best practices to commercial builders to make future low-energy buildings even more efficient.” Key lessons outlined in the report, Lessons Learned from Case Studies of Six High-Performance Buildings, include: owners provide the main motivation; set measurable energy saving goals; proper integration in the design, installation, and operation of the building energy-saving technologies can change how buildings perform; an integrated whole-building systems design approach is needed to achieve energy goals; and energy performance must be tracked and verified following completion. “In the United States, new commercial buildings are added to the building stock faster than old buildings are retired,” added Rodgers. “Conducting research to evaluate the state-of-the-art in energy-efficient buildings as we know it now puts us in a better position to inform the next generation of low-energy commercial buildings.” This study — along with a network of partners in state government, research, academia, construction, design, and utilities — support DOE’s goal to create the technology and knowledge base for marketable zero-energy commercial buildings by 2025. Zero-energy buildings are designed, constructed, and operated to generate the same amount of energy they use each year, resulting in a net-zero energy consumption.