On the eco-trade show circuit five years ago, Jennifer Gangi could provide a raft of technical information for fuel cells, but lacked referrals to give to interested architects and builders. Although the principle of fuel cell technology was discovered in the late 1830s, it wasn’t until the 1950s and 1960s that work began on it in earnest. Heading into the 2000s, there were small demonstration projects, but no commercialized products or systems. Not anymore. “Now I can point to a flurry of name-brand corporations that have completed fuel cell projects,” says Gangi, the program director for Fuel Cells 2000, an independent Washington, D.C.based advocacy group. “And, there is a wider range of vendors with fuel cell products to offer.”
In fact, fuel cells are helping to power hundreds of buildings, according to Gangi. One example is eBay’s June 2009 installation of five 100kW Bloom Boxes, developed by Bloom Energy in Sunnyvale, Calif. Located on concrete slabs at grade level just outside eBay’s new Building 17 in San Jose, Calif., the tidy row of SUV-sized fuel cells takes up 3,000 square feet. By contrast, the 3,248 rooftop solar panels atop five buildings, including the LEED Goldcertified Building 17, which was designed by Chicago-based Valerio Dewalt Train Associates (VDTA), cover a whopping 55,000 square feet.
Since fuel cells run 24/7, the boxeswhich, according to Bloom, typically generate power at 8 to 10 cents per kWhwill provide 15 percent of the campus’ electricity per year, according to eBay. Bloom anticipates the boxes will pay for themselves in three to five years, and, according to VDTA, when combined with the solar panels, they will help to reduce the campus’ total power consumption by 33 percent.
What’s in the Box
While Bloom touts its new ceramics-enabled technology as superior, it’s only one of about six types of fuel cells currently available. Fuel cells are classified by the electrolyte used. So, while Bloom’s products are classified as solid-oxide fuel cells, other options used in buildings are phosphoric acid, proton exchange membrane, and molten carbonate fuel cells. Each type has advantages depending upon the type of fuel source used. Some rely on biogas, while others use natural gas. Regardless, all rely on chemistry rather than combustion.
According to Fuel Cells 2000, every type of fuel cell consists of two electrodes and an electrolyte. The electrodes are located on each side of the electrolyte, and all three are then enclosed in a casing. Similar to the electrochemical process in everyday batteries, oxygen passes over one electrode and hydrogen over the other, generating electricity, water, and heat.
“In principle, a fuel cell is similar to a battery,” Gangi explains. “But, a fuel cell doesn’t run down or require recharging. As long as hydrogen is supplied, it keeps running.”
Most types of fuel cell systems run on hydrogen-based fuel, which can come from hydrocarbon-based fuel cellssuch as natural gas, methanol, or gasolineor even renewable methods such as landfill-created biogas. This is made possible by including either a fuel reformer or fuel processor as a system component, which extracts the hydrogen from the fuel of choice.
Although individual fuel cells are small and generate only about 0.7Vabout enough to power a 60W incandescent light bulba fuel cell system is a “stack” of individual cells. “Cells are stacked until the desired power output is reached, making fuel cell systems very flexible and scalable,” Gangi says.
The heat produced by a fuel cell system also can be reclaimed. Systems that do this are called combined heat and power plants (CHP). These systems can even produce cold air when an absorption chiller is installed. The water used in the process turns into vapor. As noted by the Whole Building Design Guide, a program of the National Institute of Building Sciences in Washington, D.C., fuel cell systems convert about 40 percent to 50 percent of the available fuel to electricity, and 85 percent or more for CHP systems. This compares with 20 percent to 40 percent for traditional fossil fuelfired power plants.
In addition, fuel cells emit 60 percent less carbon dioxide than combustion-fired piston engines at a significantly reduced noise level (about 60 decibels at 100 feet). Indeed, some leading hotels with fuel cell systems have located them next to tennis courts without disrupting players’ concentration.
From a design and installation perspective, the architects of eBay’s Building 17 report that the fuel cells were an unremarkable energy sourcethey primarily required running a gas and water line. “Otherwise, we just had to find a route for bringing the electrical infrastructure into the main utility room,” says Anthony Caliz, a VDTA associate and director of the firm’s California office.
The real challenge for incorporating the 7-foot-tall boxes was timing. “The green energy push began when the project was 75 percent finished,” Caliz says. “Since the boxes are like having five cars parked in front of a building, forever, it would’ve been better to integrate them earlier, during the design phase.”
In the end, the boxes were placed outside the building’s windowless data center to minimize sight line impact. “For the next project, Building 16, we’ll have a chance to plan ahead and be more strategic,” Caliz says.
Yet another obstacle was that the fuel cell manufacturer was a start-up. “At the time, Bloom lacked an implementation team,” Caliz says. “So, the project became more orchestration than architectural design.”
Today, the company has an implementation team in place, according to Bloom’s Asim Hussain, director of product marketing. And, it provides “turnkey installation and provisioning.”
Regardless, eBay’s boxes have proven nearly maintenance-free, says Caliz. “The units have their own internal sensors, which Bloom monitors,” he explains. “Techs are in the field to fix even the smallest issues, well before anyone knows there is a problem.”
Anne Rawland Gabriel writes about technology from Minneapolis-St Paul.