Applications and limitations
There are thousands of fuel cell power systems deployed in telecommunications applications in the U.S. Wireless telephone carriers are some of the biggest adopters of the technology since fuels cell systems provide much longer runtimes for backup power applications. There is also very little maintenance for fuel cells as compared with the need to replace batteries every two years or the costs to maintain thousands of backup generator systems. Perhaps the largest benefit is the ability of the fuel cell systems to operate continuously over long periods of time. Since Hurricane Katrina, the federal government has mandated that wireless carriers maintain 8 hours of backup power (at a minimum) at each site. When compared with the traditional battery-backup system, fuel cells provide longer runtimes for a given footprint. The runtime is only limited by the size of the fuel supply. The fuel cell also weighs much less than the amount of lead acid batteries required for the extended operation — this is a real consideration when located in the upper floor of a building.
In terms of broadcast applications, PEMFC systems would not be suitable to run full power transmitter sites. The largest PEMFC systems will provide up to 7kW of dc power. The systems can be ganged to increase the capacity, if necessary. In practical use, these systems are most suitable for applications where you now use large battery-based, uninterruptable backup power systems. These might include data centers, engineering rooms, small studios, remote trucks, remote microwave sites and low power backup transmitter sites. Fuel cells would also be the ideal power source for any emergency plans such as portable, trailer-mounted, low-power emergency transmitter systems and studios.
Cost for PEMFC systems are about $3,000 per kilowatt, that would make the cost of a 5kW system approximately $15,000. Installation might add another $2,000. While $17,000 is a little higher than the equivalent battery-based UPS or generator backup, tax credits could lower the purchase price of the PEMFC $5,000 or more putting it well within range of the traditional methods. Also when you consider the total cost of maintenance over 5, 10 or 15 years between a generator or battery UPS, the PEMFC becomes about 30 percent cheaper, since there are no expensive batteries to replace and dispose. Fuel cells have no moving parts, which eliminates the mechanical issues and repairs found in reciprocating, engine-driven generator systems. Perhaps the greatest benefit of PEMFC systems is that they are considered a green power alternative, which gives your company some bragging rights.
The installations of PEMFCs are specifically addressed in all national and most state and local building codes including NFPA and IBC. A lot of the differences between fuel cells and other power systems in the codes have to do with the handling of the fuel, fuel piping, ventilation and location of the system.
McNamara is president of Applied Wireless, Cape Coral, FL.
Want to know more about PEMFC and other fuel cell systems? The U.S. Department of Energy has a site dedicated to efficient and renewable energy sources including fuel cells. www.eere.energy.gov