The California Public Utilities Commission is pursuing zero net energy buildings in the commercial and retail sector as a way to increase energy efficiency and cut the future need for electricity. The move—discussed during a public workshop at the commission June 5 and 6—embraces the American Institute of Architect’s “2030 Challenge.” That architectural strategy seeks to cut building energy use by 50 percent immediately, then starting in 2010 by another 10 percent every five years until new structures are “carbon neutral” beginning in 2030. Today, buildings consume 48 percent of the nation’s energy, according to Ed Mazria, Mazria Odems Dzurec partner and inventor of the 2030 Challenge. However, most of those buildings will be replaced or renovated over the next 30 years, he notes, opening an opportunity to cut energy use and greenhouse gas emissions dramatically. Net zero energy buildings are defined as those which are carbon neutral. They typically employ enough energy efficient design features, fixtures, appliances, insulation, windows, and photovoltaic panels that they can feed the grid as much energy as they draw when averaged over a year. Southern California Edison endorsed the concept, but pointed out that the biggest challenge will be to achieve zero net energy use on big buildings, particularly those in hot inland areas of the state. So what’s involved in building a zero net energy building and will it work in hot desert areas? A National Renewable Energy Laboratory Study, Assessment of the Technical Potential for Achieving Zero-Energy Commercial Buildings, sheds light. The 2006 study found that by using “currently available” technologies and design features, 22 percent of new commercial buildings representing 23 percent of commercial building floor space nationally could achieve net zero energy use. In inland portions of California, 38 percent of commercial floor space could achieve the zero net energy use mark. These technologies include: -Covering half of roof space with solar panels; -Placing exterior fixed overhangs over glass on the south facing side of buildings; -Installing “super insulation and super windows;” -Using centralized chilled-water-based air conditioning with advanced efficiency features and highly efficient gas heating; and -Installing the most efficient lighting systems available. The report said increases in the efficiency of photovoltaic panels, lighting, and the wide range of electronic devices used in buildings—from appliances to computers—will be needed to enable more commercial structures to operate as zero net energy buildings.