Fuel Cells Explained

Fuel Cell Applications & Issues

Stationary Applications

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Residential Applications

In residential applications, small fuel cell power plants could be installed for the production of both electricity and heat or hot water for the home.

In addition to homes in developed countries, where the market may first develop, an ideal application for fuel cells is to provide power to remote residential entities that have limited or no access to primary grid power, thereby delaying, if not eliminating, the necessity of expensive, maintenance intensive transmission line installations. These applications will be more common in developing countries, where fuel cells can provide electricity in regions gradually as development warrants and allows.

There are a number of companies developing and / or producing residential fuel cells, some of those include:

Commercial Applications

Commercial application refers to applications that are connected to a business. Examples include an apartment building or complex, an office building, strip mall or a hotel.

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Data Centers

The propagation of Data Centers throughout the U.S. and the developed world, is a sign of continued growth in the digital age and also a significant burden on grid generation and transmission capacity. The power use density for these facilities can be in excess of 100 watts per square foot resulting in very high electrical demands for a relatively small facility. These same facilities are extremely dependent on premium quality and highly reliability power.

The potential for cogeneration at these facilities is low, however the development of the Data Center Campus concept allows cogeneration to be implements beyond the confines of the Data Center in surrounding process, office, or hospitality relate buildings. The waste heat of a fuel cell can be converted to chilled air through the absopbtion chilling process, a definite need for such a data center facility.

Case Study
In 1999, the First National Bank of Omaha (FNBO) - the nation's largest privately owned bank-installed a 800-kw fuel-cell system as the primary power source for its new 200,000 square foot Technology Center's critical loads. This bank is the nation's seventh largest credit card transaction processor, handling over three million transactions per day, 365 days a year. According to officials at the bank, a single one-hour blackout could cost FNBO's credit card operation as much as $6 million in lost business.

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Benefits and Attributes

System Configuration:

  • Two IFC (Model: PC25C) 200 kW fuel cells (400 kW total)
  • One 1250 kW Prime rated diesel generator
  • Two 260 kW Piller Uniblock rotary UPS units
  • One 1.6 MW, 10 Second ride through, 3400 rpm, 10 ton flywheel
  • Dual independent electric, gas, and communication services to facility

System Operation:

  • 340 kW of high-availability power for the critical load
  • Because there are two redundant cells, 400 kW of excess power is produced and used to power non-critical loads. This power decreases the bank's utility demand charges as well as the cost of the displaced power.
  • 2.8 million BTU/hour [of heat] that can be used for both heating and cooling (using absorption chillers) by the bank.
  • The system produces reliable power 99.9999 percent of the time (six 9's). Typical combination set-ups of electricity from the utility grid and back-up generators is "three 9s" which equates to 53 minutes of down time a year, whereas this fuel cell system, with six 9's reliability, is expected to be down only 31 seconds a year.

Natural gas consumed = 47.73 million scf of natural gas

Electricity produced = 4950 MWhrs per year

Heat recovered = 9.5 x 109 btu per year

  • Noise emissions: 62 dBA at 30 feet

System Costs

  • Installed cost = $3.8 million or $4,750 / kW. There are a number of rebate programs available state to state as well as a federal buydown program, utilized by the Bank, through the U.S. DOD of $1,000 / kW.

Maintenance

  • Annual maintenance costs = $120,000
  • Recurring maintenance = $175,000/cell to replace cell stack at year 7
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Institutional Applications

Industrial applications refer to general group of large-scale applications that typically incorporate multiple buildings. Examples include universities and colleges, prisons, government or military facilities.

In these applications, the ability to generate electricity and heat onsite has multiple benefits including the utilization ofheat forair cooling, laundry facilities, cafeteria facilities, preheating water for onsite boilers.

Opportunity Fuel Applications

There are a number of applications where the byproducts of a process, create fuels (hydrocarbons) that can be utilized by a fuel cell to generate electricity. High temperature fuel cells (solid oxide and molten carbonate) are probably most aptly suited for this application, as they are able to more easily tolerate the contaminants in the fuel. However, the bulk of installations to date have used phosphoric acid fuel cells from UTC Fuel Cells.

Examples of these various applications:

Landfills
According to the EPA, landfills are the largest source of anthropogenic methane emissions in the U.S., constituting almost 40 percent of these emissions each year. Methane is a potent greenhouse gas; each pound of methane emitted from a landfill is about 25 times more effective at trapping radiation in the atmosphere than a pound of carbon dioxide. Recovery and use of methane from landfills substantially reduces these emissions while capturing their energy value. In 2002, EPA estimated that up to 750 landfills could economically recover their methane for energy, yet only about 140 projects are in place.

Anaerobic Digesters - Waste Water Treatment Facility
An anaerobic digester is a municipal waste treatment system that produces a methane-rich gas, which can be used by a fuel cell.

Anaerobic digestion is a biochemical process in which particular kinds of bacteria digest biomass in an oxygen-free environment. Several different types of bacteria work together to break down complex organic wastes in stages, resulting in the production of "biogas."

Controlled anaerobic digestion requires an airtight chamber, called a digester. To promote bacterial activity, the digester must maintain a temperature of at least 68° F. Using higher temperatures, up to 150° F, shortens processing time, allowing the digester to handle a larger volume of organic waste. The waste heat from fuel cells can be used to facilitate this process.

The biogas produced in a digester (also known as "digester gas") is actually a mixture of gases, with methane and carbon dioxide (CO2) making up more than 90 percent of the total. Biogas typically contains smaller amounts of hydrogen sulfide, nitrogen, hydrogen, methylmercaptans and oxygen which must be processed in order not poison a fuel cell.

Case Study:
In October 1999, the first project in California to produce electricity from human waste by-products, was dedicated at the Rancho Las Virgenes Composting Facility in Calabasas. The joint venture of Las Virgenes Municipal Water District and Triunfo Sanitation District provide wastewater services to more than 80,000 residents in western Los Angeles County and eastern Ventura County. Facilities of the joint venture include Tapia Water Reclamation Facility and Rancho Las Virgenes Composting Facility.

In the past, this methane gas, which is a profound contributor to global warming, has been flared in the open air. The municipal water district proposed to install a cogeneration plant to burn the methane as fuel, but permitting issues with the South Coast Air Quality Management District (SCAQMD) held things up.

The $2.6 million project was financed by a $958,240 California Energy Commission grant, plus $400,000 from the U.S. Department of Defense (under the Climate Change Fuel Cell Program), with the balance covered by the Joint Venture partners. The expectation is to recoup this investment within less than 10 years; because of the money saved, the district will not be purchasing power from an outside source.

The two 200 kW Phosphoric Acid Fuel Cells, made by International Fuel Cell, convert the methane gas (120,000 cubic feet of methane gas produced daily), a by-product of the composting plants process, into hydrogen which is used in the fuel cell to produce electricity. The 400 kWs produced are able to provide for the needs of 300 households.

"After nine months of operation, the fuel cell provided 75 to 90 percent of the facility's electricity at a price somewhere between five and six cents per kilowatt hour (kWh) - if costs are amortized over 20 years. It was estimated that if the municipal utility district was served by Southern California Edison, its bottom line costs would add up to a figure near 25 cents per kWh. The fuel costs are zero. Maintenance costs are just a little more than a penny per kWh."

In addition to utilizing the electricity, the excess heat generated at the fuel cells also is used to heat the digester (95 C required to breakdown the biosolids into methane), reducing operation costs. When you factor in the heat recovery, these fuel cells are able to show efficiencies between 80 and 90 percent.

DG / Stationary Resources:

DGen ProTM Software

DGen ProTM software is for corporate facility managers, gas and electric utility representatives, energy service companies, and distributed power generation equipment manufacturers.DGen ProTM helps determine the economic viability of on-site and distributed generation projects. A new version 3.0 is now available with major enhancements. Its flexible "wizard" interface accesses an extensive library of information, including cost and performance data on natural gas distributed generation products, electric and gas rates, and prototypical building loads. More information is available by contacting Mike Romanco of GTI or following this link: http://www.archenergy.com/dgenpro/default.htm

The NFCRC does not necessarily endorse this product but lists it as a resource and for informational purposes only.

DG Reports and Publications

Modeling Distributed Electricity Generation in the NEMS Buildings Models
Currently, the National Energy Modeling System (NEMS) buildings models characterize several distributed generation technologies:  conventional oil or gas engine generation, combustion turbine technologies, and newer, still developing technologies such as solar photovoltaics (PV), fuel cells, and microturbines.  This paper describes the modeling techniques, assumptions, and results for the Annual Energy Outlook 2000 reference case.  In addition, a series of alternative simulations are described, and key results for distributed generation are presented.

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