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Fuel cell study provides answers for OPPD, clean power for zoo
It is only natural that organizations dedicated to protecting the world's wildlife should take an interest in technology that protects the environment, too. With the help of Omaha Public Power District (OPPD), the Henry Doorly Zoo pioneered the use of a hydrogen fuel cell generator to power zoo facilities. OPPD installed a fuel cell at the zoo's Lied Jungle in 2001 as part of a pilot project to learn more about the technology. "Some accounts were asking us about fuel cells, and we wanted to see if this was an option OPPD should be offering customers," said Senior Media Specialist Mike Jones. Project a good fit for both partnersThe Lied Jungle indoor rainforest provided an excellent setting for Nebraska's largest municipal utility to take an in-depth look at fuel cell operation, maintenance, reliability and availability issues. The world's largest indoor rainforest has 123,000 square feet of floor space housing cliffs, caves, waterfalls, lush vegetation and animals from Asia, Africa and South America. Before installing the fuel cell, the zoo relied on two 60-kW co-generation units to maintain the necessary climate conditions. The noisy units had frequent breakdowns and required a great deal of maintenance. There were many reasons OPPD considered the zoo a good candidate for the fuel cell project. The Lied Jungle is a 24-hour load factor requiring a substantial amount of electricity. Also, the zoo is close to OPPD, making it accessible to district employees who must maintain the unit. Perhaps most importantly, said Jones, "OPPD and the zoo have a very healthy working relationship." The fuel cell project is one of many OPPD has undertaken to help the zoo control its energy use. OPPD worked with the zoo to centralize its cooling operations into a single plant. The system produces ice at night, in off-peak hours, to meet cooling needs of several major zoo facilities during the day. Another project increased the zoo's energy efficiency by installing a computer system to monitor, analyze and control energy use throughout the zoo's campus. The partners are currently looking at increasing the zoo's electricity supply by installing a new circuit. The initial power purchase agreement covering the fuel cell's generation kept things simple for the zoo. OPPD charged the zoo only for the electricity it consumed, while the utility owned, operated and maintained the unit. That arrangement continues today, four years after the conclusion of the pilot project. "We have been pleased and have learned much," Jones observed of the project. "OPPD will continue to operate the fuel cell for the foreseeable future." Fitting fuel cells into utility operationsOPPD bought the fuel cell from International Fuel Cells Inc.—now UTC Power—for $800,000. A grant from the U.S. DOE's Fuel Cells program for $200,000 helped offset the cost. After a great deal of study and review by OPPD engineers, a phosphoric acid fuel cell was selected for the test. "It was one of the only fuel cells big enough to meet the Lied Jungle's power needs, and to show how distributed generation might impact our bottom line," said Jones. The unit also gave OPPD a different type of fuel cell technology to compare with a system the First National Bank of Omaha installed in 1999. Training utility employees to operate and maintain the fuel cell was an important piece of the learning curve. OPPD sent five operations and maintenance technicians to UTC's headquarters in Connecticut for a five-day class that included hands-on training. "The cell is completely computer controlled, so it is essential that technicians are able to work with a laptop computer for operation and troubleshooting diagnostics," Jones said. He added that most large utilities would have personnel with the basic skills and knowledge needed to work with the fuel cell. "Not everyone who works on the cell needed to attend the class," Jones noted, pointing to the natural gas issue as an example. "Our technicians already knew that the higher nitrogen content in the Midwest's natural gas mix could poison the fuel cell. The training class gave them the chance to see how that problem played out." The problem itself was fixed by adding a nitrogen scrubber to the natural gas supply line when the fuel cell was installed. That was the first and last modification OPPD made to the unit. With only routine maintenance, the fuel cell has operated at 95 percent availability for the last three years. "It has so far performed as well if not better than expected in terms of efficiency and reliability," Jones said. The zoo's fuel-cell system has been more successful, in fact, than some units OPPD tested with the now-defunct IdaTek. The 5-kW systems were proton exchange membrane-type fuel cells, one installed at Offutt Air Force Base outside of Omaha, and the other at a facility in Elkhorn, Neb.The smaller units just seemed to be less reliable than the zoo's 200-kW fuel cell, Jones recalled. Lessons learned from zoo cellThe zoo project was also successful in providing OPPD with enough experience to form some useful conclusions about fuel cell operation and applications. A fuel cell system performs best and is most economical when it runs at full capacity and as much of the waste heat as possible gets used. The zoo captures waste heat from its fuel cell to temper water for wildlife ponds, provide humidity and supply hot water for its restaurant. The more hot water a facility needs, the better the economics are likely to be. Adding the infrastructure to capture the waste heat adds to the installations cost, however. Facilities with loads that require an uninterrupted power supply will need to install a backup generator—another expense—to supply power when the cell is down for maintenance or due to mechanical failure. The power from fuel cells is much more expensive than from conventional power sources. OPPD estimates that a kilowatt-hour (kWh) from a hydrogen fuel cell costs about 15 cents, compared with as little as two cents/kWh from coal-fired units. Having a long-term contract in place for the natural gas supply could help to protect the system owner against price volatility. Congress has begun exploring possible tax credits and other efforts that could bring down the cost of fuel cell generation. A carbon tax would also improve the equation for the emissions-free power source. Doorly Zoo starts, others followEven without incentives, the fuel cell's environmental benefits can outweigh the high cost for organizations that count conservation and education as a critical part of their mission. The American Zoo and Aquarium Association promotes ecological responsibility, and the Wildlife Conservation Society and other zoo operators are adopting sustainable practices. The Bronx Zoo's award-winning, sustainable redesign of its Lion House in 2005 included a fuel cell. As part of its Fuel Cell Demonstration Program, the Los Angeles Department of Water and Power unveiled its 200-kW Zoo Fuel Cell Power Plant in 2006. Fuel cells can be even more practical for temporary installation. The Smithsonian National Zoo in Washington, D.C., used a Microcell 1-kW fuel cell to help power last year's annual holiday ZooLights exhibit. Located at one of ZooLights entrances, the unit generated not only power, but also a lot of public interest and excitement for the technology. It looks like installing a clean, quiet generator to power zoo facilities and educate the public about renewable energy has become an industry trend. Omaha's Henry Doorly Zoo, a world-renowned leader in animal conservation and research, has become a leader in sustainability as well. Thanks to a leader in customer service—Omaha Public Power District. |
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