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Case Studies: Fuel Cells - The First National Bank of Omaha

Distributed Generation: Fuel Cells Deliver High-Quality Power in Critical Applications
Published: 11/13/00

At a Glance Natural Gas Fuel Cells:

  • High reliability/availability, low maintenance
  • High energy conversion efficiency (up to 80 percent with cogenerated heat recovery)
  • Clean power; by-products of water, CO2, and useful heat
  • Quiet, trouble-free operation requiring no air conditioning
  • Fuel flexibility (natural gas, propane, biogas, landfill gas)
  • Modular design
  • Rapid load response

Fuel Cell Basics
Sir William Grove introduced the concept of fuel cells in 1839, when he theorized that the process of electrolysis (splitting water into hydrogen and oxygen) might be reversed. The term "fuel cell" was coined in 1889, but 19th century technological limitations and the advent of the internal combustion engine delayed further research for many decades.

Beginning in the early 1960s, the U.S. National Aeronautic and Space Administration (NASA) supported advances in fuel cell technology, and all manned American space missions have used fuel cells to provide electricity and drinking water for the astronauts.

Typically, a natural gas fuel cell power plant has three sections: 1) a fuel processor, which reforms the gas to enrich its hydrogen content; 2) a power section, which produces direct current (DC) electricity and heat by combining the hydrogen with oxygen from the air; and 3) a power conditioner, which converts the DC electricity to alternating current (AC) and also virtually eliminates voltage spikes and harmonic distortions. Individual cells are arranged in "stacks" to provide the required level of power.

During the electrochemical process, ions move through an electrolyte between the negatively charged side (cathode) and the positive (anode). Catalysts facilitate reactions between the electrolyte and the anode or cathode. Scientists categorize fuel cells by the type of electrolyte used. The most fully developed technology uses phosphoric acid electrolyte, though progress is also evident using molten carbonate and solid oxide electrolytes and proton exchange membranes.

Almost anyone can identify with the frustration of a computer failure, whether it happens at work or at home. Once your screen goes blank or your computerized machine stops running unexpectedly, you know you're in for some headaches. That's why fuel cells - one of many distributed generation technologies - are capturing a market in critical applications that require a reliable, high-quality power source. Fuel cells generate electricity at the customer site through an electrochemical process, without combustion.

In addition to high efficiency and low emissions, fuel cells deliver excellent power quality, and redundant fuel cell systems can match the reliability requirements of the most advanced computers. Today, many manufacturers are working on a variety of fuel cell technologies ranging in development status from commercially available to futuristic.

The 24/7 Information Age
Nearly all businesses and industries now depend on computers for their operations, often their most critical processes. Industries requiring reliable, high-quality power for critical computer applications include silicon wafer fabrication; chemicals, plastics, and food processing; and financial operations such as banks, insurance companies, and credit card transaction processing. Many of these corporations do business 24 hours a day, 7 days a week, around the world. About 85% of corporate information resides in mainframe computers and large servers. As the Internet continues to grow around the clock, web hosting and telecommunications facilities are also accelerating demand for uninterruptible electricity.

With downtime costing thousands of dollars a minute, U.S. businesses are losing billions each year due to computer failures caused by electricity problems. It takes as little as 8/1000ths of a second to crash a computer system, often destroying valuable data. According to a U.S. Department of Energy report titled Making Connections power quality and reliability are likely to get worse, not better, as deregulation of the electric industry proceeds.

Comparing the "Nines"
Until recently, businesses with critical computer needs have invested in either uninterruptible power supply (UPS) systems to condition the electricity coming from the utility grid, or batteries and standby generators to supply power onsite when the grid fails. Most UPS systems have an "availability" of 99.9 to 99.99%, meaning the equipment is available to operate for that percentage of the time. But even these levels are inadequate for computers. New servers can operate up to 99.999% of the time, and high-end mainframes feature up to 99.9999% availability. These percentage figures are frequently referred to as "nines" - UPS systems reach three to four nines, while computers reach five to six nines. The catch is that each nine represents an order of magnitude, so the "uninterruptible," conditioned power source is 10 to 1,000 times more likely to fail than the computers themselves.

Bank Relies on Fuel Cell System
For round-the-clock processing, The First National Bank of Omaha is the nation's seventh-largest credit card processor and also provides data processing services for dozens of smaller banks. After a battery-powered backup system failed during a power outage in 1993, the bank decided to install an ultra-reliable power system, incorporating four fuel cells, at its state-of-the-art Technology Center in downtown Omaha. The PC25™ natural gas-powered fuel cells, each producing 200 kW, were manufactured by ONSI Corp. (South Windsor, CT).

The bank's Technology Center resembles a high-tech beehive honeycombed with computers and servers. Designed expressly as a data center with tornado-hardened construction, the 200,000-square-foot, three-story complex houses hundreds of employees who process millions of dollars daily in checks and credit card transactions. An hour of computer downtime would cost the bank roughly $6 million, including good will.

The natural gas fuel cell system, supplied and operated by Sure Power Corp. (Danbury, CT), offers an availability of 99.9999%, exceeding that of the bank's computer system. "The reliability of the 'six 9s' computer-grade electricity that Sure Power delivers isn't a luxury for us," says Dennis C. Hughes, Director of Property Management for First National Buildings, Inc. "It's a critical difference over existing power arrangements that will substantially increase our computer uptime. The result is a tremendous leap in our competitive advantage. With Sure Power, First National can raise our customer's service expectations while generating higher revenues."

The Sure Power system requires minimal maintenance (36-hour annual service shutdown for each fuel cell) and runs without technicians at the site - instead, more than 1,000 parameters are remotely monitored. Diagnostics and early-warning alarms allow time for trained technicians to arrive on site and make repairs before anything goes wrong. Also, the fuel cell system can be sited outdoors without air conditioning in ambient temperatures of -40º to 104ºF (-40º to 40ºC); some cooling and exhaust were provided to the bank's indoor system.

Metropolitan Utilities District (Omaha), the local gas utility, was involved in the project from the beginning and offered financial incentives for the fuel cell installation, according to Dave DeBoer, Utilization Engineer. "The quality of power this system provides is second to none," he says. "The use of fuel cells for distributed generation increases our market infiltration into areas we were not able to crack before. It is also more economically feasible for us to purchase gas for a level, round-the-clock base load." The utility is exploring other high-quality power customers and hopes to include applications in the residential market.

Redundant System Design
Two of the four 200-kW natural gas fuel cells are the primary source of power for the Technology Center's critical computer load of 340 kW. The other two redundant fuel cells generate 400 kW of excess electricity, which reduces the bank's utility demand charges. A total of 700,000 Btu/hr of heat is recovered in the form of hot water and is used in the winter to heat the building and to melt ice and snow outdoors, using special coils built into the sidewalks. During the summer, dry-coolers dissipate the heat.

At the bank's request, two 1,250-kW Cummins-Onan diesel engine-powered generator sets were incorporated and are used on site for life safety support within the system; a 10-day supply of diesel fuel is stored nearby. In the case of fuel cell failure, rotary equipment - two 5-ton steel flywheels - made by Piller, Inc. (the U.S. subsidiary of a German company) can supply electricity for 30-45 seconds until the engine/generators can carry the load.

Natural gas for the fuel cells is supplied through two mains fed from different gas distribution sources, and two separate electric utility feeders were installed from different substations to provide the building's normal (non-critical) electrical service. Power loss to critical loads would require the loss of three fuel cells, two diesel generators, and two utility feeders, according to Thomas J. Ditoro, P.E., Electrical Project Engineer, HDR Architecture, Inc. (Omaha, NE). HDR designed the building and engineered the electrical system.

Performance and Cost
The Sure Power system was delivered to the bank's Technology Center in December 1998 and began operating in May 1999. "It has out-performed even our wildest dreams," says Hughes. The bank is expanding its processing services to smaller banks using the fuel cell system's high level of availability as a marketing tool. As designed, the system can accommodate planned growth through 2002 plus an additional 30% increase in load. Also, the installation has become a showcase, attracting interest from engineers and businesses around the world.

One unique advantage of the Sure Power system is its low emissions - so low that California has exempted it from air quality regulations. The Omaha bank's system produces 40-50% less greenhouse gases than a traditional UPS system that draws its power from the electric grid. This reduction would apply to other regions where electricity is produced from coal or other non-hydro/renewable sources and where the customer has a use for at least half of the fuel cell's heat.

The Technology Center has been operating its fuel cells at 75% capacity because of a high concentration of nitrogen (8%) in the natural gas supply. A membrane system was recently installed to reduce the gas's nitrogen content by 2.5%. Over a one-year period (May 10, 1999-May 10, 2000), the fuel cells consumed a total of 47.73 million scf of natural gas (average of 1362 scf/hr per fuel cell, vs. 1900 scf/hr at full load) and produced 4950 MW of electricity. The overall efficiency of the fuel cell system (including heat recovery) was 54.1%.

According to a life cycle cost analysis by Ditoro, the fuel cell system is slightly less expensive than a parallel redundant UPS system over a 20-year life, even though it has a higher installed cost.

Currently, Sure Power offers modular fuel cell systems in sizes from 400 kW to 20+ MW with long-term service contracts covering all but the natural gas fuel. The company can also provide financing and installation. Preliminary discussions are taking place with a major East Coast telecommunications company and a medical research facility; each are considering a 2-MW installation. Talks with various potential customers could result in orders exceeding 40 MW.