Natural Gas Fuel CellsTechnology for improving energy efficiency while reducingenvironmental emissions

• They can be sized to accommodate dif-ferent capacity needs by “stacking” thesame cell designs.

• Their high conversion efficiency is rela-tively independent of system capacity.

• They are environmentally benignbecause of their low emissions.

At present, however, only one type ofNGFC system is commercially availablein the United States, the phosphoric-acid-based fuel cell. The phosphoric acid oper-ates as the electrolyte in the power section.Three other electrolytes are still beingtesting in other fuel cell designs: moltencarbonate, solid oxide, and polymerelectrolytes.

Technology SelectionThe NGFC is just one of many energy

technologies to emerge in the last 20 years.The FTA series targets technologies thatappear to have significant Federal-sectorpotential and for which some Federalinstallation experience exists. These FTAsseek to identify if product claims are trueor are simply sales hype.

New technologies were identifiedthrough advertisements in the CommerceBusiness Daily and trade journals, andthrough direct correspondence. Numerousresponses were obtained from manufactur-ers, utilities, trade associations, researchinstitutes, Federal sites, and other inter-ested parties.

FederalTechnology

Alert

A publication seriesdesigned to speed the

adoption of energy-efficient and renewable

technologies in theFederal sector

Prepared by theNew Technology

Demonstration Program

The U.S. Department of Energyrequests that no alterations bemade without permission in anyreproduction of this document.

A natural gas fuel cell (NGFC) is asimple, reliable way to improve natural gasutilization and efficiency. This technologyconverts natural gas into electricity to pro-vide a quiet, clean, and highly efficienton-site electric generating system and ther-mal energy source that can reduce facilityenergy service costs by 20% to 40% overconventional energy service.

This Federal Technology Alert (FTA),one of a series on new technologies,describes the theory of operation, energy-saving mechanisms, range of applica-tions, and field experience for the NGFCtechnology.

Energy-Saving MechanismThe NGFC is a simple, reliable direct

conversion system. A fuel cell is an elec-trochemical system rather than a combus-tion system. Its operation is closely akinto that of a battery system, except that itconsumes fuel. The energy savings resultsfrom the high conversion efficiency, typi-cally 40% or higher, depending on the typeof fuel cell. When utilized in a cogenera-tion application by recovering the avail-able thermal energy output, overall energyutilization efficiencies can be on the orderof 85% or more.

The figure below shows the primarysubsystems of an NGFC. An additionalthermal management subsystem (notshown) may be required if cogenerationthermal energy is not fully utilized. Thereare several types of NGFC, all having thefollowing general characteristics:

Technologies suggested were evaluatedin terms of potential energy, cost, and envi-ronmental benefits to the Federal sector.They were also categorized as those thatare just coming to market and those forwhich field data already exist. Technolo-gies classified as just coming to market areconsidered for field demonstration throughthe U.S. Department of Energy’s FederalEnergy Management Program (FEMP)and industry partnerships. Technologiesfor which some field data already existare considered as topics for FTAs. TheNGFC technology was found to havesignificant potential for Federal-sectorsavings and to have demonstrated energy-saving field experience.

Potential BenefitsBesides the possible cost savings avail-

able with NGFC, there are environmentalbenefits associated with installing thistechnology. Because NGFCs convert fuelto electricity through an electrochemicalprocess rather than a combustion process,the emissions are much cleaner, primarilycarbon dioxide and water. The low emis-sion levels have attracted the attention ofmany air quality management districtsaround the country, and some districtshave granted NGFCs blanket exemptionfrom air quality permitting. This exemp-tion could become a major factor in thedecision to install and operate an NGFC,especially in areas where new permits arenot being issued or in instances whereoperational emissions levels are beingexceeded.

ApplicationOn the basis of FEMP analysis and

review of evaluations by others, the NGFCtechnology is recommended for deploy-ment at Federal facilities when it can beapplied in a cogeneration configuration asa base load electric and thermal supplysystem. The following conditions favoruse of an NGFC system:

• Where natural gas costs are low andelectricity and demand costs are high

• Where the thermal energy can berecovered and utilized (the NGFCcan become more cost effective operat-ing as a cogeneration system)

• Where compliance with stringent envi-ronmental air quality regulations islimiting the options available to meetelectric power requirements

• Where critical electric loads are cur-rently being supplied by high-costuninterruptible power supplies, motor-generator sets, or back-up generatorsrunning on fossil fuels

determining the cost effectiveness of a200-kW phosphoric-acid-based NGFC.The analysis uses the San Diego Gas andElectric (SDG&E) general service-large-time metered secondary electric rate sched-ule (AL-TOU) and the GPTCI natural gasrate schedule for the local cost of energy.

Assuming the fuel cell is operated con-tinuously at full load and that 75% of theavailable thermal energy can be recoveredand used to offset the load of an existingboiler system operating at 80% efficiency,the fuel cell energy consumption is deter-mined and evaluated against the value ofthe avoided electricity costs and the valueof the avoided boiler fuel consumption.Annual maintenance costs for operatingthe fuel cell are estimated at $26,000/yr.The estimated cost of the NGFC is$600,000 with an additional $50,000 forinstallation. However, with the Federalcost sharing program, the net cost to thesite is estimated to be $450,000. The lifeof the NGFC is estimated to be 20 years.Life-cycle costs were determined using theNIST Building Life-Cycle Cost (BLCC)program. The total life-cycle cost for theNGFC alternative was calculated to be$1,908,000, compared with conventionalenergy service with a life-cycle cost of$2,007,000, for a net-present value of over$99,000. The savings-to-investment ratio(SIR) for installing the NGFC was 1.22.

This case study is only an example.The actual implementation of NGFC tech-nology is unique to each site. Readersinterested in a specific application areencouraged to contact the NAFCOG orthe NGFC manufacturer’s representativeto identify an owner/operator with a simi-lar application or installation.

Implementation BarriersThe future of natural gas fuel cells in theFederal sector looks good. There are manypotential applications for fuel cells, includ-ing prime power supply, interruptible powersupply, and cogeneration supply. Becauseof the potential for reducing site emissions,improving power quality, and increasingpower reliability, as well as the life-cyclecost economics, the market for natural gasfuel cells is anticipated to grow.

The only remaining barriers to imple-mentation involve gaining user acceptanceof this alternative energy production tech-nology and reducing the initial cost of theNGFC.

Federal energy managers and technol-ogy program managers who are familiarwith NGFC systems are listed in this FTA.The reader is invited to ask questions andlearn more about the NGFC technology.

• Where computers, telecommunicationsequipment, electronic security systems,or other electronic control systemsdemand a noise-free, highly reliable,high-quality electric energy source.

An NGFC system is least cost-effectiveunder the following conditions:

• In a cogeneration configuration for usein either a thermal-load-following orelectric-load-following control strategy.In these strategies, the fuel cell operatesat some part-load factor. Dependingon the relative natural gas and electriccosts, full-load operation (base loading)typically offers the best life-cycle-costeconomics.

• In systems using sophisticated thermalrecovery and control systems that aredesigned to recover the maximumavailable thermal energy. In thesesystems, the cost of the thermal energyrecovery equipment may outweigh thepotential economic benefit.

Field ExperienceNGFC installations have been monitored

in many commercial sites and a few Federalsites by utility engineers and site facilitymanagers. Feedback from owners/operatorshas been extremely positive. System elec-tric conversion efficiencies of 40% andavailabilities of 97% or more are beingreported on the latest models installed.The experience gained and the lessonslearned from the commercial NGFC sys-tems installed to date have conclusivelyvalidated the phosphoric-acid fuel cell(PAFC) technology.

The only negative feedback receiveddealt with initial installation, permitting,and/or electric grid interconnection issuesrather than actual system operation or per-formance. During the installation of over20 units throughout the country, only twopermitting issues were raised and thosehave already been addressed by the PAFCmanufacturer.

Owners and operators have joined toform an independent users group, theNorth American Fuel Cell Owners Group(NAFCOG), to share information on appli-cations, siting, installation operation andmaintenance experiences. The reader isstrongly encouraged to contact the mem-bers of this group. Contact names andphone numbers are listed in the FTA sec-tion “Who is Using the Technology.”

Case StudyA hypothetical case study from a

Federal facility in southern California wasdeveloped to illustrate the process for

About the Federal Technology AlertsThe Energy Policy Act of 1992, and

subsequent Executive Orders, mandatethat energy consumption in the federalsector be reduced by 30% from 1985levels by the year 2005. To achieve thisgoal, the U.S. Department of Energy’sFederal Energy Management Program(FEMP) is sponsoring a series of pro-grams to reduce energy consumptionat federal installations nationwide. Oneof these programs, the New TechnologyDemonstration Program (NTDP), istasked to accelerate the introduction ofnew energy-saving technologies intothe federal sector and to improve therate of technology transfer.

As part of this effort, FEMP, in ajoint venture with the Department ofDefense’s Strategic EnvironmentalResearch and Development Program(SERDP), is sponsoring a series ofFederal Technology Alerts that providesummary information on candidateenergy-saving technologies developedand manufactured in the United States.The technologies featured in the Alerts

have already entered the market andhave some experience but are not ingeneral use in the federal sector. Basedon their potential for energy, cost, andenvironmental benefits to the federalsector, the technologies are consideredto be leading candidates for immediatefederal application.

The goal of the Alerts is to improvethe rate of technology transfer of newenergy-saving technologies within thefederal sector and to provide the rightpeople in the field with accurate, up-to-date information on the new technolo-gies so that they can make educatedjudgments on whether the technolo-gies are suitable for their federal sites.

Because the Alerts are cost-effectiveand timely to produce (compared withawaiting the results of field demonstra-tions), they meet the short-term needof disseminating information to a targetaudience in a timeframe that allows therapid deployment of the technologies—and ultimately the saving of energy inthe federal sector.

The information in the Alerts typi-cally includes a description of thecandidate technology; the results ofits screening tests; a description of itsperformance, applications and fieldexperience to date; a list of potentialsuppliers; and important contact infor-mation. Attached appendixes providesupplemental informationand exampleworksheets on the technology.

FEMP sponsors publication of theFederal Technology Alerts to facilitateinformation-sharing between manu-facturers and government staff. Whilethe technology featured promises sig-nificant federal-sector savings, theAlerts do not constitute FEMP’sendorsement of a particular product,as FEMP has not independently veri-fied performance data provided bymanufacturers. FEMP encouragesinterested federal energy and facilitymanagers to contact the manufacturersand other federal sites directly, and touse the worksheets in the Alerts to aidin their purchasing decisions.

Strategic EnvironmentalR&D Program

The Strategic Environmental Research andDevelopment Program, SERDP, co-sponsorof these Federal Technology Alerts, was cre-ated by the National Defense AuthorizationAct of 1990 (Public Law 101-510). SERDP'sprimary purpose is to "address environmen-tal matters of concern to the Departmentof Defense and the Department of Energythrough support for basic and applied researchand development of technologies that canenhance the capabilities of the departmentsto meet their environmental obligations."In 1993, SERDP made available additionalfunds to augment those of FEMP, for thepurpose of new technology installationsand evaluations.

Federal Energy Management Program

The federal government is the largest energy consumer in the nation.Annually, in its 500,000 buildings and 8,000 locations worldwide, it usesnearly two quadrillion Btu (quads) of energy, costing over $11 billion.This represents 2.5% of all primary energy consumption in the UnitedStates. The Federal Energy Management Program was established in 1974to provide direction, guidance, and assistance to federal agencies in plan-ning and implementing energy management programs that will improvethe energy efficiency and fuel flexibility of the federal infrastructure.

Over the years several federal laws and Executive Orders have shapedFEMP's mission. These include the Energy Policy and Conservation Actof 1975; the National Energy Conservation and Policy Act of 1978; theFederal Energy Management Improvement Act of 1988; and, most recently,Executive Order 12759 in 1991, the National Energy Policy Act of 1992(EPACT), and Executive Order 12902 in 1994.

FEMP is currently involved in a wide range of energy-assessment activi-ties, including conducting New Technology Demonstrations to hasten thepenetration of energy-efficient technologies into the federal marketplace.

For More Information

FEMP Help Desk(800) 363-3732International callers please use (703) 287-8391Web site: http://www.eren.doe.gov/femp/

General Contact

Ted CollinsNew Technology Demonstration ProgramProgram ManagerFederal Energy Management ProgramU.S. Department of Energy1000 Independence Avenue, SW, EE-92Washington, DC 20585(202) 586-8017Fax: (202) 586-3000theodore.collins@hq.doe.gov

Technical Contact

Steven A. ParkerPacific Northwest National LaboratoryP.O. Box 999, MSIN: K5-08Richland, Washington 99352(509) 375-6366Fax: (509) 375-3614steven.parker@pnl.gov

Produced for the U.S. Department of Energyby the Pacific Northwest National Laboratory

November 1995

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