It may be a first: an office building with a net electricity use of zero or less, that burns no fossil fuels for heating and produces no greenhouse gas, and that makes the people working there at least as comfortable as those in conventionally heated and cooled buildings. The building, in San Jose, Calif., opens in October, and if all goes according to plan, it will raise the bar for designers of energy-efficient buildings worldwide. Though other so-called z-squared buildings exist, they are highway rest stops, nature centers, and event locations, not office structures with computers and printers and cubicles full of employees.
”We’ve hoisted the flag and said we’re the first,” says David Kaneda. ”No one yet has stepped forward to question that.” He owns the San Jose building, and his Santa Clara, Calif.�based firm, Integrated Design Associates (IDeAs), did the electrical and lighting design and will occupy the ground floor.
David Kaneda shows off the solar panels and skylights of his new building.
The building was once a windowless bank, designed in the 1960s when banks were meant to be riot-proof concrete bunkers. Today, with the remodeling nearly completed, it is modern art: the exterior is broken up with rows of windows and swaths of blue and gray paint, while solar panels adorn the roof, with skylights pushing up in between.
Kaneda embarked on the project of renovating the old bank in September 2005, with the goal of creating an environmentally friendly building that could earn a Platinum rating—the highest—from the U.S. Green Building Council, an association of builders in Washington, D.C. At that time, global climate change was not in the forefront of public consciousness, and the council’s standards were not much in the public eye. So Kaneda thought he was being very forward-thinking when he proposed to renovate the bank to meet the council’s specifications for building materials, water use, indoor air quality, and—most important—energy use.
But when Kaneda hired architect Scott Shell, from EHDD Architecture, in San Francisco, to work on the project, Shell went even further, suggesting they design a building with no net electricity usage and no carbon dioxide emissions.
”It was a shock to me when he said that,” Kaneda recalls. He didn’t know of any commercial buildings that had gone that far.
The idea appealed to Kaneda, and the two decided they would disconnect the natural gas pipes running to the building and find heating alternatives. They would stay on the electric grid but install enough photoelectric panels to cover the entire energy load—about 30 kilowatts, generating more electricity than the building uses during the day but pulling a small amount off the grid at night. Since they’d be limited by the size of the roof, they’d have to be clever about energy use.
”To cut down on energy use, you’ve got three areas to address,” Kaneda says, ”lighting, heating and cooling, and plug load—that is, the computers, printers, microwave ovens, and other things you plug into the wall.”
To reduce the amount of energy used for lighting, Kaneda’s builders sawed through the concrete perimeter of the building to install windows and skylights. Special window glass lets visible light through but blocks infrared and ultraviolet light, keeping the office cool. An overhang on the south side shades the windows from direct sun; on the east side, electrochromic glass controlled by a sensor darkens the windows when sun hits them directly and makes them transparent the rest of the day. Because the ceilings are high, the skylights bathe much of the office space in a diffuse light; in areas where the skylight illumination is too strong, Kaneda is experimenting with different types of diffusers.
The building also uses low-energy fluorescent bulbs, some of which are hooked up to switched circuits, while others are on dimmers. Kaneda wasn’t able to get any good data on which method is more energy efficient, so he plans to collect his own data, which will be invaluable to others embarking on similar projects.
For heating and cooling, Kaneda chose a geothermal heat pump, which takes advantage of the fact that at some point below the surface, the ground remains a constant 10 °C all year round. In Northern California, this point is only about 1.8 meters below ground level; Kaneda installed water pipes that snake throughout the property, an area that will eventually have a landscaped courtyard and a bocce court. When the water flows into the building, it goes through a heat exchanger that collects the heat from the ground in winter and pulls heat out of the building in summer.
Designers of energy-efficient buildings often stop at this point, but for Kaneda, once the first two areas of energy use had been addressed, the amount of energy allocated to computers and other plug-in devices looked huge. All the appliances he purchased for the common room meet the U.S. Department of Energy efficiency goals, and all his employees’ computers will have LCD screens, the lowest-power option. Light and motion sensors will turn on electric lights when daylight gives way to evening and employees are still working, but employees will be able to adjust their personal light levels from their desktop computers. Arming the building security system, which is supposed to happen when the last person leaves for the night, will automatically cut off the power-sucking printers—Kaneda’s own large-format printer, the worst power vampire, draws 40 watts in standby mode.
Kaneda won’t know for sure just how efficient the building will be until he and other tenants—yet to be determined—move in later this fall, but he’s confident he’ll be putting more energy into the grid than he takes out. Though he has yet to set a policy for tenants, he hopes to attract companies that are equally concerned about the environment.
If Kaneda wins the Green Building Council’s approval, his will be among the few Platinum buildings in Northern California (only about 40 exist in the United States as a whole). But whether his will truly be a z-squared building is a matter of debate, since no official definition exists.
Meanwhile, water in underground pipes keeps things cool.
Is simply producing more energy than a building consumes enough to call it zâ''squared? Or does all the energy consumed need to be green energy? If all energy consumed has to be green, how is this guaranteed? Is buying ”green power” from the utility company enough? This may mean only that it purchases enough green energy to cover users’ needs but that it doesn’t send that actual energy to them. Or would it be better to buy carbon credits to offset any electricity imported from the grid, based on the utility’s average greenhouse-gas emissions per kilowatt generated? Paul A. Torcellini, a senior engineer with the National Renewable Energy Laboratory in Golden, Colo., notes that in real life some of the electricity you buy is bound to have been generated at the cost of greenhouse-gas emissions.
Torcellini points out that the building stock in the United States is growing faster than builders are deploying energy-efficiency technology. As a result, with buildings accounting for just about 18 percent of the country’s energy consumption, the absolute amount of energy used is increasing one-and-a-half percent per year. So ”we either need to save more or build more power plants,” he says.
Kaneda is already developing another z-squared structure, this one for the La Jolla, Calif., research building of the J. Craig Venter Institute, a biotech firm based in Rockville, Md., that is seeking to create artificial life and use genomics to solve a wide array of pressing global problems. With the name of the famed genome pioneer, J. Craig Venter, over the door, that building will get a lot of notice, even if the former San Jose bank remains known only to tech insiders.