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Fall 1995

Science and Technology at theNational Renewable Energy Laboratory

In ReviewIn Review

The National RenewableEnergy Laboratory

NREL is a national resourcecommitted to leadership, excellence,and innovation in renewable energyand related technologies.

Our research is intended forapplication in the private sector. Wefoster cooperation with industrythrough subcontracts and cost-shared studies. We collaborate withuniversity and industry researchers.Our world-class laboratories areavailable for experiments, analyses,and proprietary studies.

NREL is a DOE national labora-tory operated by the MidwestResearch Institute.

NREL In ReviewNREL’s news magazine is

intended to promote the flow oftechnology from the laboratory tothe private sector. NREL In Reviewaddresses a readership ranging fromscientific professionals to businesspeople. It is distributed withoutcharge to those involved inrenewable energy and related fields.

Material may be reprinted withproper credit. Mention of product orcompany name does not constituteendorsement by NREL, MRI, or anyagency of the U.S. government.

Linda R. BrownManaging Editor/Science Writer(303) 275-4097

Ann HansenAssistant Editor

Howard Brown, Mike Coe,Paula Pitchford, Patrick SummersContributing Writers

Susan SczepanskiDesigner and Typographer

Warren GretzCover photograph

Fall 1995 Vol. XVII, No. 3

Features3 Catching the Trade Winds

With help from NREL, American wind turbine manufacturers are movingadvanced machines into competitive world markets

8 Advancing PV TechnologyNREL’s Outdoor Test Facility offers capabilities ranging from solarradiometric measurements to simulated hail strikes

10 NREL on the InternetInformation on renewable energy and energy efficiency is now available toInternet users

12 Opening Doors for Desiccant CoolingHotels, restaurants, and office buildings may soon enjoy healthier, morecomfortable indoor air thanks to joint research supported by NREL

17 Landfill Projects That PayLocal governments find ways to turn a public nuisance into the sweet smellof success

Departments1 NREL News

Enterprise Growth Forums link companies with financing; new manager ofTechnology and Business Ventures Office; Federal Express study comparesalternative fuels; solar radiation data available on Internet; PV aidsorangutan research; improved catalytic converters for vehicles; newThermal Test Facility demonstrates energy efficiency; budget update

7 Technology TransferA new computer tool for short-term energy monitoring generates fast andaccurate predictions of energy use in buildings

14 Technical NewsNon-destructive technique measures shunt resistance of individual cells inphotovoltaic modules to quickly identify electric performance problems

19 Publications20 Calendar/Recent Reports

On the cover — This 275-kilowatt advancedwind turbine is one of several now moving intoworld markets thanks to government-industryresearch partnerships (see article p. 3).

Printed on paper containing at least 50% wastepaper,including 20% postconsumer waste. This magazine isfully recyclable at centers using the Office Pack program.

NREL News

Forums linkcompanies withfinancing

NREL’s Enterprise GrowthForums are bridging the gapbetween renewable energyentrepreneurs and the financialcommunity. Held quarterly, theforums allow venture capital-ists to become familiar withinnovative energy technologiesnow gearing up for competitiveworld markets. Growth-stagecompanies gain access to theadvice of seasoned businessexperts. Forums have beenheld in Washington, DC, eachwith more than 60 invited par-ticipants from the financingcommunity and the renewableenergy industry. The next oneis tentatively scheduled forJanuary 1996. For more infor-mation, contact NREL’s JessicaWhite at (303) 275-4358.

Meet NREL’s newtech transfermanager

NREL welcomes RichardMarczewski as the new man-ager of its Technology and Busi-ness Ventures Office. Formerlythe head of NREL’s hybrid vehi-cle program, Marczewski alsomanaged General Motors (GM)Corporation’s External Technol-ogy Leveraging Group. Hisduties at NREL include licens-ing new energy technologies aswell as arranging cooperativeresearch agreements and otherbusiness ventures. Marczewskiholds a master’s degree inbusiness administration fromWestern Michigan University.

Federal Expressdelivers data

Fleet operators can make bet-ter decisions about alternativefuels thanks to an extensivedemonstration project con-ducted with the help of FederalExpress and NREL’s Fuels Utili-zation Program. The two-year“CleanFleet” study involved111 delivery vans operating onM85 (85% methanol, 15% gaso-line), compressed natural gas,propane, electricity, CaliforniaPhase 2 reformulated gasoline,or baseline unleaded gasoline.The vehicles were driven a totalof more than 3 million milesin the Los Angeles area.

Among its many results,the study found that electricityand compressed natural gasmight offer the greatest reduc-tion in emissions for manyfleets. Reformulated gasolinealso reduced emissions and didnot affect vehicle reliability,although driving range wasreduced when compared to

unleaded gasoline. The flexible-fuel capability of the M85 vehi-cles helped overcome limitedlocal supplies of methanol.

Data from this study areavailable on the Internet byaccessing http://www.afdc.nrel.gov or by calling theNational Alternative FuelsHotline at 1-800-423-1363.

Solar radiation datanow online

NREL’s Steve Wilcox hasbeen working with scientists atthe World Radiation Data Cen-ter (WRDC) in Russia to makeworldwide solar radiation dataavailable on the Internet. Estab-lished 30 years ago, WRDCcollects, archives, and dissemi-nates solar radiation dataobtained at more than 1000sites. Wilcox went to Russia in1994 to assist with hardwareupgrades. He has also beenhelping Russian scientists learnmore about the World WideWeb and other data distribu-tion technologies. Internetusers can access WRDC’s database by entering http://wrdc-mgo.nrel.gov.

PV aids orangutanresearch

The world’s foremostexpert on orangutans, BiruteGaldikas, is recharging herbatteries with a new photovol-taic (PV) system. Galdikas isthe president of OrangutanFoundation International, anonprofit organization aimedat saving the near-extinct pri-mates in Borneo. She and herresearch team have been usinghundreds of batteries everyyear to provide power forlights and communicationsequipment, but battery disposal

Richard Marczewski,Manager of Technology and Business Ventures

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NREL In Review Fall 1995 1

creates environmental and logis-tical problems. A group of NRELemployees led by John Thorntonand Mike Marsh providedGaldikas with a PV system torecharge the batteries forextended use. For more informa-tion on the project, contact MikeMarsh at (303) 384-6567.

Benteler looks atvacuum insulation

More efficient catalytic con-verters may soon be on themarket thanks to cooperativeresearch between NREL andBenteler Industries Inc. of GrandRapids, MI. The company isinvestigating the use of NREL’scompact vacuum insulation forcatalytic converters, whichBenteler would produce and sellto automobile manufacturers.Catalytic converters wrappedin vacuum insulation wouldremain at efficient operatingtemperatures for 17 hours orlonger after the vehicle’s engineis turned off, thereby avoidingemissions produced by theengine during start-up periods.For more information on NREL’saward-winning technology,contact Steve Rubin at (303) 275-4099.

Thermal Test Facilitybreaks new ground

NREL has broken ground on anew 10,000-square-foot researchfacility to support developmentof advanced technology for build-ings. The new Thermal Test Facil-ity will house laboratories foradvancing research in areas suchas ventilation, heating, cooling,passive solar designs, computer-ized energy design tools, solarwater heating systems, andelectrochromic coatings forwindows. The facility will also

be a showcase for energy effi-ciency, incorporating featuressuch as clerestory windows fordaylighting, high efficiency light-ing, heat recovery, and direct-indirect evaporative cooling.

NREL captures twoR&D 100 Awards

Research and Developmentmagazine has honored twoNREL technologies with prestig-ious R&D 100 Awards, rankingthem among the nation’s top 100technical innovations of the year.

The first award went to abreakthrough that simplifies theproduction of ethanol made frombiomass, with significant costreductions in store. NRELresearchers achieved this bygenetically engineering the bacte-rium Zymomonos mobilis for moreefficient fermentation of plantmaterial to ethanol, a liquidtransportation fuel now madeprimarily from corn. The break-through also expands the kindsof feedstocks that can be used toproduce ethanol.

The second R&D 100 Award isshared with Coors Ceramics Co.of Golden, CO. The two organiza-tions are developing a novel wayto produce high quality ceramicpowders at one-third the cost ofother processes. Coors is nowbuilding a production plant atits Golden facility to meet theexpected increase in demand forsilicon carbide products, whichare used in high-temperature,high-stress applications such aspump seals for refineries andchemical plants.

For more information,contact NREL’s Technology andBusiness Ventures Office at(303) 275-3008.

Budget updateAt press time, the House and

Senate had both approved an en-ergy spending bill that couldmean a 25% to 35% cutback inDOE’s energy efficiency andrenewable energy programs ifapproved by President Clinton.The impact on NREL’s budgetis not clear yet.

DOE and NREL are alreadytaking action to reduce operatingcosts and preserve vital researchprograms. Energy SecretaryHazel O’Leary has announcedthe first steps of a budget reduc-tion plan that will save U.S. tax-payers $14 billion during thenext five years. The initial stepsinclude consolidating regionalsupport offices as well as fossil-fuel research and developmentactivities. Assistant SecretaryChristine Ervin of DOE’s Officeof Energy Efficiency and Renew-able Energy has been participat-ing in an effort to consolidatefossil energy, energy efficiency,and renewable energy programsin a new category—DOE’senergy resource business lineprograms.

NREL continues to developits three-pronged attack on thebudget challenge: improvingoperational efficiency, creatingnew business opportunities, anddiversifying income. In addition,the Laboratory recently beganoffering voluntary buyout pack-ages to employees that areexpected to reduce staff by about10%. The results of these initia-tives should reduce the impactof federal budget cuts on tech-nologies that are vital to thenation’s energy future.♦

NREL News

2 Fall 1995 NREL In Review

by Robert Ebisch

The AWT-27 wind turbine isan impressive sight—and animpressive technology. Spin-

ning atop a 140-foot tower, the tur-bine’s two-bladed propeller sweepsout a circle almost 90 feet in diame-ter. Lightweight design, sleek blades,simplified mechanical systems,

state-of-the-art controls, and aerody-namic braking make this 275-kilowattmachine a serious contender inexpanding global markets for renew-able energy.

The turbine’s manufacturer—FloWind Corp. of San Rafael, CA—is fulfilling a $30-million contract for220 of its AWT-27 machines. Theturbines will be delivered to India,where they will be assembled andinstalled in a new 50-megawatt windpower plant. This is just the begin-ning of a multi-year joint venturethat could generate orders for anadditional $50- to $70-million worthof FloWind machines next year.FloWind also has three projectsslated for China, amounting to

$160 million in sales and 180 mega-watts of new electric generatingcapacity.

The AWT-27 and the slightlysmaller AWT-26 were developed inpartnership with NREL throughDOE’s Advanced Wind TurbineProgram with funding from the

CatchingThe TradeWindsWith help from NREL,American wind turbinemanufacturers aremoving advancedmachines intocompetitive worldmarkets

“Without the collaborativeeffort, we would not havea product ready for the

market today.”— Robert Lynette

Advanced Wind Turbines Inc.

Above: Advanced Wind Turbine Inc.’s new275-kilowatt machine uses blades designedwith advanced airfoils to increase energyproduction, an innovative teetered rotor toreduce stress from wind gusts, and a strongbut lightweight tube tower. (Photo courtesyof Warren Gretz/NREL)


Office of EnergyEfficiency andRenewable Energy.

“Without the col-laborative effort, wewould not have aproduct ready forthe market today,”says Robert Lynette,who is marketingvice president ofFloWind and presi-dent of AdvancedWind Turbines Inc.,a turbine manufac-turing companyowned by FloWind.“NREL has helpedus considerablywith cost sharingand equally, if notmore importantly,with technicalsupport.”

Research part-nerships with

companies such as Lynette’s havereduced wind energy costs to about5¢ per kilowatt-hour in areas withgood wind resources. Capital costshave decreased to less than $1000 perkilowatt. But industry experts agreethat additional work is needed togive U.S. technologies a leading edgein highly competitive world markets.The next five years are critical to theU.S. wind industry, both domesti-cally and in the huge potentialmarkets of India, China, and LatinAmerica. NREL is helping its indus-try partners develop advancedmachines to meet growing demand.

Moving improved technologyinto the marketplace

According to the American WindEnergy Association (AWEA), theworld’s total wind capacity couldincrease from today’s 4000 mega-watts to as much as 50,000 mega-watts within the next decade. Of the4000 megawatts in place today,

C.A.R.E.S.Portland General Electric Co.Puget Sound Power & LightPacifiCorp

Sacramento MunicipalUtility District

Pacific Gas & Electric Co.

Southwestern Public Service Co.

Central Maine Power Co.New England Power Service Co.

Green Mountain Power Corp.

Niagara Mohawk Power Corp.

Eastern Wisconsin Utilities

Waverly Light & PowerMidwest Power Co.Interstate Power Co.Iowa Electric Light and Power Co.

Northern States Power Co.Marshall Municipal Utilities

Texas Utilities Co.

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03PacifiCorp,TRI-State,G&T Assn. Inc.,Public Service Co. of Colorado,and Eugene Water & Electric Board

Central and South West Services, Inc.

Southern California Edison Co.

Hawaiian Electric Co., Inc.

Utilities across the nation have announced plans to operate wind power plants or to purchase wind power from independent power producers.

A new version of FloWind’s vertical-axis wind turbine (shownhere) will be part of several new installations in China. The newEHD series (extended height to diameter) was developed withassistance from NREL and Sandia National Laboratories.

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about 1700 are in the United States,representing a capital investment ofabout $3.5 billion. Power purchaseagreements now being negotiatedor already in place may see another$1 billion investment in U.S. windcapacity before the end of the decade.

In particular, U.S. utilities arewarming up to the potential of newlycompetitive wind power. Some ofthe wind plants now feeding powerto utility grids are owned by utilities;others are independently owned andsell wind-generated electricity asindependent power producers.The bulk of U.S. capacity is still inCalifornia, where the wind industrybegan.

“That will be changing over thenext few years,” says AWEA’s RandySwisher. “Next year there’s an addi-tional 100 megawatts going on line inMinnesota and about 50 megawattsin Texas. Between 50 and 100 mega-watts will be going on line in thenorthwest in ‘96 or ‘97.”

Other wind plant projects, eitherplanned or under way, will servestates such as New York, Vermont,Maine, Michigan, Iowa, andWyoming. The turbines involvedin these projects are not only moreadvanced but more powerful.

For example, Zond Systems Inc.of Tehachapi, CA, has installedmore than 2500 turbines in the 30-to 250-kilowatt range since the

early 1980s. Under NREL’s ValueEngineered Turbine Program, Zondcame up with the Z-40, the U.S. windindustry’s first 500-kilowatt turbine.The company is installing its newmachines in a 6.6-megawatt powerplant for Central and SouthwestPower near Fort Davis, TX. Zondalso won a solicitation with NorthernStates Power to supply 100 mega-watts of wind capacity using the Z-40and its successor, the Z-46.

Would Zond have developed theZ-40 without NREL’s help?

“I still think we would havedeveloped the turbine anyway, butundoubtedly it would have useddifferent airfoils,” says Ken Karas,Zond’s president and chief executiveofficer. “So the machine would prob-ably be somewhat less efficient. Theblade testing would have been more

difficult to accomplish, and it wouldhave cost a significant amount ofmoney to develop test facilities.Other than NREL, such facilitiesdon’t exist in the U.S.”

Another subcontractor under theDOE/NREL Value Engineered Tur-bine Program—New World GridPower of Palm Springs, CA—isdeveloping a 500-kilowatt turbinedubbed the 500-XST. Sales projec-tions target as many as 100 of thesemachines by the end of 1996, contin-gent on prototype performance.

“For so many years, industryproduct development never came tocommercialization,” says Clare Lees,president of New World GridPower. “We think that now the pro-gram has taken the direction thatNREL and the industry should take.”

In addition to its work with small U.S. companies, NREL is providing technical support toindustry giants such as Kenetech Windpower. Researchers are testing blades for Kenetech’sKVS-33 wind turbine, pictured here.

“We had wanted to advancethe state of the technology fora long time, but the markethasn’t been big enough to

fund an internal R&D effortsuch as the one we’re

pursuing with NREL’s help.”— Ken Cohn

Second Wind Inc.


Gearing up for internationalmarkets

While domestic markets are warm-ing up, the majority of new windpower installations is expected to oc-cur overseas. For example, Arthur D.Little has projected the installation of350 to 600 megawatts in China andup to 1200 megawatts in India by theend of the decade.

“Turbines in India tend to be moreEuropean in what’s installed today,”says AWEA’s Randy Swisher. “But anumber of U.S. companies are thereright now putting in new projects.”

New World Power Co. (NewWorld Grid Power’s parent com-pany) has projects either planned,under development, or in operationin England, Ireland, Wales,Argentina, Costa Rica, Mexico,Nicaragua, Brazil, Guatemala,Chile, China, the Philippines, France,and Turkey.

But compared with the Europeanwind industry, much of the U.S.industry is still in the early stagesof development. Cost-sharing andtechnical assistance are crucial—especially for smaller companies.

“We had wanted toadvance the state of thetechnology for a longtime, but the markethasn’t been big enoughto fund an internal R&Deffort such as the onewe’re pursuing withNREL’s help,” says KenCohn, operations man-ager for Second WindInc. of Somerville, MA.The company is develop-ing a wind turbine moni-toring system and windplant controls with sup-port from an NRELsubcontract.

Bergey WindpowerCo. of Norman, OK, hasbeen developing a syn-chronous inverter with

technical assistance and joint fundingfrom NREL. Company chairman KarlBergey compares NREL’s seminal rolein the wind industry with that of theNational Advisory Committee forAeronautics (NACA), the predeces-sor of the National Aeronautics andSpace Administration (NASA).

“In my view, one of the reasonsthat our aviation industry leads theworld is that NACA, and later NASA,provided important theoretical andpractical assistance to the aviationindustry from the 1920s on,” Bergeysays. “The results of NACA’s basicand applied research were widelydisseminated. Its development facili-ties—including full-scale wind tun-nels—were available to aircraftmanufacturers for specific tests.NACA provided a solid foundationfor the phenomenal growth of theU.S. aviation industry during WorldWar II and the immediate postwarperiod. NREL appears to be servingthat same function for wind powertoday.”

As wind technology improves,NREL’s emphasis continues to

change. Five years ago, airfoil designwas the most important issue underinvestigation, and the issue of price-competitiveness appeared to bealmost resolved. Now, once again,the big technical challenge is toreduce the cost of wind power. Cur-rent technology allows wind plantsto produce electricity at rates of 4¢ to5¢ cents per kilowatt-hour.

NREL-sponsored research contin-ues to probe at the cost issue, reduc-ing costs and optimizing energyoutputs with improvements in vari-able-speed turbines, larger rotorswith increased power output, lighterstructures, more efficient controls,and simpler components. The resultsare clearly seen in the marketplace.

“We have our third NREL-supported turbine going into com-mercialization right now,” says ClintColeman, president of New WorldPower Technology Co. (formerlyNorthern Power Systems Inc.) ofMoretown, VT. The company hasworked under an NREL subcontractto develop its 250-kilowatt turbine,the North Wind 250.

“The contracts for turbine develop-ment have clearly been a direct andsuccessful way of getting industryinvolved,” Coleman says. “Over theyears, NREL has provided a lot ofsupport research that we couldn’thave done ourselves. NREL has alsobeen a world leader in developingcomputerized wind turbine designcodes. That’s something that nomanufacturer could ever do—andas you explore more flexible andlighter weight machines and moreadvanced concepts, these codes arereally essential.”

For more information on NREL’swind turbine design program, con-tact Brian Smith at (303) 384-6911.For information on research partner-ship opportunities, contact DarrellDodge at (303) 384-6906.♦

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Cost Reductions in Wind-Generated Electricity

30-year levelized cost of energyin constant 1993 dollars, basedon utility economics

5.8 meters/sec (13 mph) at10 m (30 ft) above ground

Wind energy costs now stand at 4¢ to 5¢ per kilowatt-hourand are rapidly declining, thanks to recent technologicalinnovations made by government and industry.


Technology Transfer

Predicting Energy Use for BuildingsA new NREL tool can help building designers and managers predict andmonitor energy use

Buildings in the United Statesconsume about 35% of ournation’s total energy supply

at a cost of $193 billion a year. NRELhas developed a new technique forpredicting and monitoring buildingenergy performance that could helpreduce these costs while makingour homes and businesses morecomfortable.

Called short-term energy monitor-ing (STEM), the new techniquequickly and easily predicts long-termenergy performance such as annualheating requirements. STEM is alsovery accurate; tests conducted inhomes and small commercial build-ings have shown that predictedenergy use differs from actual meas-urements by less than 5%. Thismakes STEM a valid way to verifyenergy performance for third-partyfinancing and utility rebate programs.

Architects and building managerswill find STEM useful in isolating theindividual components that affectenergy use. For example, tests canbe conducted before and after add-ing insulation, window shading, orperforming a furnace tune-up to giveprecise information on how thesechanges affect a building’s energyconsumption.

A STEM test typically takes threedays, during which a computer-controlled data acquisition systemgathers hourly energy data for analy-sis. The system automatically turnstest equipment on and off, scans datachannels, and calculates hourly aver-ages from the recorded data.

The recorded dataallow STEM to calcu-late four key build-ing characteristics:heating efficiency,building-load coeffi-cient, effective build-ing thermal mass,and effective solargain. This informa-tion is useful in deter-mining the efficiencyand effectivenessof furnaces, heatingand cooling systems,ventilation, thermalstorage, and otherfacets of buildingenergy use.

NREL researchershave conducted anextensive series oftests in a singlehouse, with testsevery 10 days for afive-month period. Each test sup-plied an independent measure ofadjustment factors and estimatedperformance during the period. Thevariation in calculated adjustmentfactors led to an expected accuracyrate exceeding 95% in predictinglong-term energy performance.

In addition, researchers haveused STEM to conduct short-termtests on 40 houses from California toVirginia. The technique is also usefulfor analyzing the energy perform-ance of smaller commercial buildingsand modular units. For example,NREL and All American Modular

Co. of Arlington, Texas, have usedSTEM to study the structural differ-ences between two modular officebuildings. Test results showed thatone design used 40% less heating tokeep the same inside temperature.

NREL researchers are expandingSTEM applications to include largecommercial buildings, includingoffices with complex heating, venti-lating, and air-conditioning systems.

For more information onSTEM, contact Doug Balcomb at(303) 275-6028.♦

Poorly insulated windows account for 25% of all heating and cool-ing requirements in the United States, at a cost of $22 billion peryear. Short-term energy monitoring can help architects predict theenergy savings possible with window shading and other buildingdesign elements.

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Advancing PV Technology

NREL’s Outdoor Test Facility offers capabilities ranging fromsolar radiometric measurements to simulated hail strikes

by Mike Coe

S ince the 1980s, photovoltaiccompanies nationwide havesent prototype cells, modules,

and systems to NREL’s Outdoor TestFacility (OTF) for testing and evalu-ation. The result has been increasedphotovoltaic performance, reliability,and safety.

Now, a new 10,000-square-footlaboratory building at the OTF fieldsite will make this collaboration evenstronger by offering enhanced facil-ity and project capabilities to the pho-tovoltaic community. Dedicatedduring a grand opening ceremonyon September 7, the building consoli-dates outdoor test activities withindoor testing and evaluation pre-viously conducted in various build-ings and trailers.

“The new OTF will allow us toconduct engineering research andcomplete exploratory performancetesting in one location under natural,simulated, and accelerated test condi-tions,” said Dick DeBlasio, managerof NREL’s photovoltaic module andsystem performance and engineeringprojects.

Testing at the OTF helps NRELand its industry partners to evaluateadvanced photovoltaic technologies.State-of-the-art laboratories, outdoortest beds, and support services areused to test and characterize over3500 photovoltaic cells and moduleseach year. The results help validateadvances in module and system per-formance as well as improve reliabil-ity and safety.

“Manufacturers and users cometo us to cross-check, calibrate, andcompare results because we haveone-of-a-kind test and measurementsystems here,” DeBlasio said.

Indoor testing undercontrolled conditions

Indoor activities include modulecharacterization, environmentaldurability testing, electrical andmechanical integrity testing, diagnos-tics, failure analysis, and solar radio-metric measurements.

In a high bay area, large chambersare used for accelerated environ-mental durability testing. Modulesare subjected to elevated and control-led temperature, humidity, and lightstress factors to evaluate their capac-ity to withstand outdoor conditionssuch as temperature cycles, dampheat, humidity-freeze, and long-term

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Above: Photovoltaic systems will be installedon the front roof of the new laboratory build-ing to test systems under actual operatingconditions.


exposure to sunlight or ultravioletlight.

Mechanical tests include flexingmodules 10,000 times at differentangles and firing standardized,specially-made, one-inch-diameterice balls at modules at an impactvelocity of 52 miles per hour to simu-late hail strikes.

In a laboratory painted black toprevent light reflection, researchersuse pulse and continuous simulatorsto measure photovoltaic conversionefficiency under standard test condi-tions. The pulse simulator usesrapid, short bursts of light, while thecontinuous simulator uses a steadylight source. Both simulators areneeded to fully characterize modules.

In another lab, modules are sub-merged in water, then subjected toelevated voltages ranging from 2000to 3000 volts to measure currentleakage. Tests evaluate electrical insu-lation and verify that moisture willnot enter active portions of a module,which could cause corrosion, groundfaults, or electrical safety hazards.

Other laboratories are used fornondestructive and destructive test-ing; accelerated testing to reproduce

failure modes and mechanisms; pre-paring modules and cells for testingand outdoor deployment; and fordeveloping, characterizing, andevaluating solar simulators andrelated equipment.

Outdoor testing underreal conditions

At the OTF field site, more than100 modules and six systems arebeing tested and evaluated for per-formance, reliability, and energyproduction under prevailing outdoorconditions.

NREL is also monitoring twosix-kilowatt systems mounted atopthe nearby Solar Energy ResearchFacility (SERF), and a 15-kilowatt sys-tem in New York. Real-time data onperformance of these modules andsystems is sent to the OTF’s outdoortest and measurement laboratory foranalysis.

The two systems at SERF, five ofthe six systems at the OTF, and theNew York system are connected tothe local utility grid, providingNREL with valuable real-world expe-rience under actual utility conditions.

State-of-the-art laboratories,outdoor test beds, and

support services are used totest and characterize over

3500 photovoltaic cells andmodules each year.

Setting standardsNREL researchers also work with

industry to set uniform and consen-sus standards and codes. This workprovides guidelines for test methodsand design techniques by estab-lishing specific steps or criteria tofollow when testing or designingmodules or systems. These consen-sus standards (IEEE, ASTM, IEC)represent good engineering and test-ing practices. They are coordinatedthrough an NREL-sponsored annualstandards and code forum.

Improving test methodsThe OTF is helping NREL and the

photovoltaic industry to advancephotovoltaic technologies. But astechnologies continue to improve, somust test and evaluation methods.

“The test methods needed toevaluate new photovoltaic technolo-gies must be developed in collabora-tion with industry and validated toensure the technologies perform reli-ably and safely,” DeBlasio said.

The OTF helps make this possible.For more information on industry

partnerships and NREL’s capabili-ties, contact Dick DeBlasio at (303)384-6760.♦

More than 100 modules and six systems are now being tested under actual operating conditions.

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by Patrick Summers

At NREL, we’re taking agiant step forward tobecome the source of

renewable energy information onthe Internet.

NREL’s newly redesigned “HomePage” gives the Laboratory’s on-linepresence a sharper focus on researchand technology applications. Infor-mation on basic research, interna-tional energy developments, andbusiness issues— as well as state andlocal initiatives— are literally at yourfingertips.

Here’s a closer look at several keyareas of information available onNREL’s Internet Home Page.

News and currentevents

This is where you will findNREL’s news releases, a calendar ofconferences and special events, andinformation on how to get specialproducts such as videotapes onrenewable energy and energy effi-ciency technologies.

What’ newYou can locate information in

any of NREL’s on-line subject areasaccording to a key word or phrase.Just use the query interface listedunder “What’s New.” Also foundhere is a breakdown of NREL publi-cations by subject. This is a listing ofNREL-produced publications in awide range of research areas avail-able to the public.

NREL


The hybrid vehicle program’sHome Page offers graphics, simula-tions, and performance data in a waydesigned to help you learn abouthow hybrid vehicles work.

Research andprogram activities

This is a detailed look at NREL’sresearch divisions and provides awealth of technical and programinformation.

For example, under the AlternativeFuels Division is the Biofuels Informa-tion Center, which offers a biofuelsupdate newsletter and a nationalbiofuels data base.

Research andbusinessdevelopment

Two main components of this sec-tion are International Programs andthe Technology and Business Ven-tures Office. Through colorful graph-ics you can click on any continent andget information on doing business inmore than a dozen countries under In-ternational Programs. The Technol-ogy and Business Ventures Officewill show you how to do businesswith NREL. It covers cooperative re-search and development agreements,licensing agreements, and how to useNREL facilities.

Referenceresources

This section is a bonanza of usefuldata bases and information. TheAlternative Fuels Data Center is here,along with resource maps for solarradiation and wind energy. TheNREL photograph file offers a varietyof images related to renewableenergy research and development.

Renewable energyinformation on theInternet

NREL is part of a larger DOE net-work of energy-related Internet sites.One of these is EREN, which canpoint you in the right direction withalmost any energy-related question.♦

The best way to discover what’s available fromNREL on the Internet is to be a browser: visit theweb site and have a look. NREL’s Home Pageis continually being developed and updated.To access NREL’s Home Page, use the Internetaddress http: //www.nrel.gov.

Home PageHome Page

on the Internet


Opening Doors forDesiccant CoolingHotels, restaurants, and office buildingsmay soon enjoy healthier, morecomfortable indoor air thanks to jointresearch supported by NREL

by Linda R. Brown

B usinesses in the UnitedStates could save $750 mil-lion and offset the use of

500,000 barrels of imported oil everyyear by capitalizing on advances indesiccant cooling technology.

Desiccant systems use materialssuch as silica gel to remove moisturefrom the air while cooling it. Soliddesiccant materials are often embed-ded in a rotating wheel, where theycan be dried and regenerated forcontinued use by exposing them toheat. Because desiccants remove waterfrom the air without condensing it,they control humidity more effectivelythan air conditioners. They also oper-ate without the use of chlorofluorocar-bons (CFCs) and can handle the largerflow rates of outside air required bynew indoor air quality standards.

For the past decade, this technol-ogy has proven its worth in ware-houses, supermarkets, ice skatingrinks, and other places where control-ling humidity and temperature areimportant. But high costs have pre-vented desiccant systems from com-ing into widespread use in otherapplications such as hotels, restau-rants, and office buildings. Andthat’s where the total energy savings

could add up to asmuch as 0.3 quadrillionBtu’s per year.

With funding from DOE’s Officeof Building Technologies, NRELis working with the Gas ResearchInstitute and several U.S. manufactur-ers to make this happen. Activitiesinclude testing advanced desiccantmaterials, developing computerizeddesign codes for desiccant systems,and evaluating the performance ofdesiccant wheels using NREL’s sophis-ticated facilities.

The most significant near-termbreakthrough may come with the useof natural gas—instead of electric-ity—as an inexpensive energy sourcefor drying and regenerating desic-cant materials. As more desiccantcooling systems come into use andprices decline, markets are expectedto open up for solar-driventechnology.

Expanding markets with gasThe potential for gas-fired desic-

cant cooling is illustrated by a recentstudy of a 346,000-square-foot officebuilding in Houston, TX. New stand-ards for indoor air quality requirean outside-air ventilation rate that’sthree to four times the current prac-tice. But the building’s heating, venti-lation, and air-conditioning (HVAC)

system was unable to handle such alarge increase in air volume andmoisture.

Two options were considered:adding a vapor-compression chillerwith a 500-ton capacity, or addinga gas-fired desiccant system to theexisting 850-ton chiller. Analysisshowed that the gas-fired desiccantoption would save $27,100 annuallyin energy costs when compared withthe conventional approach.

Even more savings could be real-ized by improving the performanceof desiccant cooling systems drivenby natural gas. With support fromDOE’s Gas Cooling Program, NRELis helping several U.S. companiesevaluate a variety of desiccant mat-erials, components, and systemconfigurations.

Industry partners includeEnglehard/ICC Technologies ofPhiladelphia, PA, which is develop-ing dehumidifiers based on titaniumsilicate desiccant. This material maybe able to be adsorb (remove) moremoisture than other desiccants andto regenerate at lower temperaturesfor greater energy savings. NRELis also testing silica gel and lithiumchloride wheels for Munters/Cargocaire of Massachusetts, which

NREL researcher Doug Powell displays desiccant dehumidifierwheels in various stages of testing and development.

War

ren

Gre

tz,

NR

EL


uses the material in desiccant sys-tems for supermarket applications.

These and other cost-shared part-nerships with companies such asU.S. Rotors and Air Technology Sys-tems, both of Maryland, primarilyinvolve material and componenttesting. In 1996, NREL plans to testwheels from LaRoche Industries ofBaton Rouge, LA, and SEMCO Manu-facturing of Columbia, MO. Withfurther funding, tests can proceed tothe systems integration stage.

Benefits aboundIn addition to assisting individual

companies as they bring improvedproducts into the marketplace,NREL’s desiccant cooling researchwill generate many benefits for theindustry in general.

For example, testing will result inan extensive data base of desiccantcooling options that can help archi-tects, building managers, and con-sumers make objective, informeddecisions about which technology isappropriate for a specific application.In addition, the American Societyof Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE)will use NREL-generated data toevaluate its proposed commercialstandard for dehumidifiers.

Future studies of desiccant coolingsystems will help improve indoor airquality in buildings throughout the

nation. Accurate, modular, easy-to-use system models can be integratedinto HVAC and building simulationprograms. Research should allow thedevelopment of handbooks, charts,and user-friendly software for use byanyone interested in alternatives toconventional air conditioning.

So far, NREL’s cooperativeresearch has focused on solid desic-cants such as silica gel and polymers.But upcoming efforts will involvequalified industry partners in thedevelopment of advanced liquiddesiccants.

For more information on desiccantcooling technology, contact NREL’sSteve Slayzak at (303) 384-7527.♦

A walk through NREL’s desiccant cooling test facilitiesWith funding from DOE’s Office of Energy Efficiency and Renewable

Energy, NREL has developed a complementary set of experimental facili-ties to evaluate new and promising desiccant materials, measure the per-formance of prototype systems, and validate mathematical models forfuture design efforts. The output from each evaluation facility serves as in-put for the next one. If initial tests show promise, both the observed resultsand the validated models can be used to gather information for newer orlarger test specimens.

The characteristics that cause water to adsorb (cling) to a desiccantmaterial are measured with a quartz crystal microbalance or other equip-ment as determined by the form and shape of the sample. Promising desic-cant materials are bonded or embedded in a dehumidifier matrix materialso that adsorption properties can be confirmed at this stage of componentproduction.

Performance characteristics of desiccant matrices are measured in thedesiccant heat- and mass-transfer test facility. If the dehumidifier matrixstill shows promise, NREL researchers can build a prototype rotating dehu-midifier wheel for analysis in the HVAC test facility. The resulting datacan be used to evaluate the wheel’s performance under real operating con-ditions. Other HVAC components can also be tested, including evapora-tive coolers, heat exchangers, heat pipes, and cooling coils.

Another NREL facility examines the effects of contamination by degrad-ing desiccant samples in a controlled manner. The eventual goal is toevaluate strategies to prevent or mitigate degradation. The result shouldbe more compact, cost-competitive desiccant cooling systems with servicelifetimes of 15 years or more.

Supply air

Returnair

Evaporativeelements

Heat input forregenerationExhaust

CD-SS25-B013104

Heatexchanger

Ambientair

Solid desiccants such as silica gel or Type 1M material are embedded on a rotating wheel. Whenmounted in the cooling system, the material removes moisture from air passing through it. Thewheel is dried and regenerated using a heating source such as natural gas.


New Tool for PV DiagnosticsA non-destructive technique measures shunt resistance of individual cells inPV modules to quickly identify electric performance problems

by Howard Brown

I t’s simple, it’s free, and it quicklygives you accurate quantitativedata for one of the more impor-

tant characteristics of individual cellsin a photovoltaic (PV) module. Toooften overlooked, shunt resistance isone of the most basic and informa-tive parameters of PV performance.

Low shunt resistance of individualcells should be one of the first signsto look for in identifying electricalperformance problems with PV mod-ules. Until now, however, once amodule was encapsulated, it was nolonger practical to measure thoseresistances.

NREL researchers recently devel-oped a method that allows easy andaccurate measurement of the shuntresistance of each cell in a series-connected, encapsulated module—without damaging the module. Thetechnique is quick and simple, requir-ing only standard, inexpensive elec-tronic equipment.

Powerful diagnosticElectrical shunts are low-resistance

leakage paths that divert currentaway from the intended power loadin PV systems. For PV modules withotherwise effective materials and

design, shuntlosses are a pri-mary symptom ofproblems that cancause cell failure orpoor performance.

Cells with verylow shunt resis-tance are effec-tively dead. Cellswith marginalshunt resistancemay function ade-quately at highlight levels, but notat low levels. Agreater proportionof cell output islost under reducedlight, so that theirefficiency decreasesdramatically. Also,cells with localizedshunts—as possi-bly indicated by

marginal shunt resistance—may bemore likely to short out and failwhen subjected to the stresses ofenvironmental exposure and whenconnected together as a generatingsystem.

NREL’s shunt-resistancemeasurement technique isparticularly valuable for

assessing thin-film moduleswithout damaging them.

Shunt resistance is a particularlypowerful diagnostic parameter. Itapplies to any normal light condi-tion, not just the one under which itwas measured. Because shunt resis-tance is quantitative, you can setthreshold values for quality controland compare values from differentcells or modules. You can also checkthe values again after stress testingor regular use or if the module laterfails. Shunt-resistance values can alsobe used in computer models to pre-dict the performance of modulesunder the varying light intensitiesfound at particular locations.

Measuring shunt resistance canhelp you detect problems with indi-vidual cells that are not readilydetectable by traditional full-modulecurrent-voltage (I–V) tests. TheNREL technique is most accurate

10

8

6

4

2

00 0.2 0.4 0.6 0.8 1.0

CD-SS25-B013106

Mod

ule

effic

ienc

y(%

)

50 ohms/cell shunt resistance

1 ohm/cell shunt resistance

Light intensity (kW/m )2

Individual cell shunt resistance of1.75, 0.25, 1, 0.25, and 1.75 ohms

This graph shows calculated maximum power conversion efficienciesfor a “good” module (50 ohms/cell shunt resistance) and for“marginal” ones with lower shunt resistance.

Technical News


for the low shunt-resistance valuesthat indicate problem cells.

The per-cell-average slope of amodule’s current-voltage curve atshort-circuit current is a good indica-tor of the shunt resistance needed foreffective performance. Resistanceless than that slope indicates a seri-ous shunt; less than several timesthat slope will be only marginal.

Simple and nondestructiveTaking less than a minute per cell

to measure, the NREL techniquegives cell-by-cell shunt resistance formodules with any number of series-connected cells. It does so withoutremoving protective cover materialto get at individual cells or otherwisedamaging the module.

As far as we know, this is the onlynondestructive test for measuringshunt resistance of individual cells.The technique requires an AC signalgenerator, a DC voltage supply,an operational amplifier, and aphase-sensitive amplifier—all com-mon laboratory equipment.

This remarkably simple techniqueis based on sequentially blocking thelight to each cell in a module, measur-ing the open-circuit resistance, andsubtracting the open-circuit resis-tance of the fully exposed module. Ifthat difference is small, the cell haslow shunt resistance that will signifi-cantly impair module performance.

Many valuable applicationsTesting the shunt resistance of in-

dividual cells is valuable for allphases of the product life cycle of PVmodules. Measuring shunt resistancecan verify the adequacy and optimi-zation of cell fabrication steps. It canbe used for module performancecharacterization and qualificationtesting. During manufacture, it canbe an excellent quality-control andquality-assurance tool. And it is veryhelpful for failure analysis.

Fabrication verification can bedetermined by shunt-resistancetesting. Because measurements arequantitative and can be easily taken

at any step in the production process,it is possible to pinpoint at whichstep problems are introduced. Forexample, visual defects do not neces-sarily cause performance problems.Shunt-resistance measurementwould tell whether visual defects areof concern and would also identifyproblems that may have no visiblemanifestation.

Module performance testingassesses module output during expo-sure to see how performance willchange with time and use. Shuntresistance of individual cells can bequickly measured at the beginning ofthe test period and again at desiredintervals. It will often show problemsthat other module diagnostic tools donot. Modeling that includes shunt-resistance values can predict per-formance for the actual sunlightlevels at a particular location.

Qualification testing screens mod-ules for reliability and durability.Shunt-resistance testing can providean electrical baseline, including

NREL’s technique for measuring the shunt resistance of individual cells in a photovoltaic module needs only inexpensive, readily available equipment.

Tom

McM

ahon

,NR

EL


immediate identification of problemcells, and can then be repeated at anystage of the full qualification testprocedure.

Quality assurance/quality controlcould benefit greatly from NREL’sshunt-resistance measurement tech-nique. The technique can be auto-mated for a particular moduledesign, providing rapid quantitativeassessment at any desired step inthe production process. Minimumacceptable shunt-resistance limits canbe set, and patterns of low resistancecan point out problems with the pro-duction process. For example, for

thin-film modules, low-resistancecells occurring at the same spot inthe module may indicate a scribingproblem or a problem with themanufacturing system.

Failure analysis determines whatwent wrong with modules that havefailed. Shunt resistance is an exactvalue that enables direct quantitativecomparison of cells to other problemand nonproblem cells. Shunt-resistancetesting identifies the individualcells that have electrical problems.Researchers can then examine thosecells using microscopic or chemical

analysis or other diagnostic tools tolook for possible root causes.

Thus, in all phases of the PV-module product life cycle, NREL’sshunt-resistance measurement tech-nique quickly locates individual cellsthat are poor contributors to the elec-trical performance of the module,providing a focus for further investi-gation and corrective action.

For more information on NREL’sshunt resistance measurement tech-nique, contact Tom McMahon at(303) 384-6762.♦

Just follow these steps(1) Set up a circuit consisting of a low-frequency (2 to 10 Hz) AC voltage

source (signal generator), a DC voltage source, and an operational ampli-fier connected to a phase-sensitive, lock-in amplifier.

(2) Connect the circuit to a 1000-ohm resistor and set the AC voltage(which will be 2 to 5 millivolts) to get a reading of 1 millivolt on the lock-inamplifier.

(3) Replace the resistor with the module to be tested. Set the DC voltagesource to match the open-circuit voltage of the module for the light condi-tions under which it will be tested (sunlight through a window—about 30mW/cm2—is fully adequate).

(4) With the module exposed to constant, uniform light, simultaneouslyapply both the DC and AC voltages to the terminals of the module and

record the lock-in amplifier reading.This voltage reading is the inverseof the resistance; divide 1000 by thisvalue to get the shunt resistanceof the entire module (RA in theequations).

(5) Sequentially darken each cellof the module by covering it withopaque tape or an appropriatelyshaped rubber mat and record thereading for each cell (RB in theequations).

(6) The difference in resistancebetween the reading for each cell asit is covered and the reading with nocells covered is the shunt resistancefor the covered cell (RC in theequations).

Step 4: R = RA Σ i

Step 5: R = RB Σ i

Step 6: R R R R - RC B A≡ - = i i

If R >> R , then R R - R RB A C = i i i≈

by experience, R RC ≈ i

If R R , then cell is shunted;B A≈ i

+ Ri

light

light

light

light shunt

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107

CD-SS25-B013105

Constant,uniformbias light

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* Converts current to voltage** Measures voltage but can be read as resistance (1000/voltage)

System calibratedso that 1000-ohm

resistanceproduces a

1-mV output

PV Module(N series-connected

cells)

Vsignal

generator

ac

Vsource

dc

Lock-inamplifier**

Operationalamplifier*

≈ 3 mV peak-to-peak, 1–10 Hz

≈ V (open-circuit voltage)oc


by Mike Marsh

H ow often can a local govern-ment make money by com-plying with health and

environmental regulations? That’swhat some cities and counties aredoing as they employ new technol-ogy to turn landfill gas into salableelectricity, heat, and steam.

Pending regulations from the U.S.Environmental Protection Agencywill require as many as 700 landfillsto control emissions from decompos-ing garbage. Volatile organic com-pounds in landfill gas interact withnitrous oxides in the air to formozone, a primary constituent ofurban smog. In addition, the buildupof methane—the main energy compo-nent of landfill gas—sometimes can

be dangerous. More than 40 landfillfires and explosions resulting in 10human fatalities have been recordedin the United States.

But methane and other landfillgases can be safely collected and usedto generate revenues rather than com-plaints, as these state and local or-ganizations have discovered.

Rhode Island earns royaltiesAs environmental manager of

Rhode Island’s Central Landfill,Dennis aRusso doesn’t have to worryabout odors from decomposing gar-bage. That’s because the gas from hiscompany’s landfill is captured andconverted to electricity. The enter-prise rakes in almost $600,000 in roy-alties per year for Rhode Island SolidWaste Management Corp., a state-chartered organization responsiblefor managing the landfill.

“There’s no reason to have a land-fill and not recover the gas,” aRussosaid. “It’s a huge advantage—it’spositive all the way around.”

The 154-acre Central Landfillreceives about 90% of the state’sgarbage. In the early 1980s, residents

from the nearby town of Johnstonbegan complaining about odors fromthe site. Rhode Island Solid WasteManagement hired a private com-pany to study gas flow and assessthe feasibility of using gas to gener-ate electricity for profit. The resultsof the study were positive. In 1989,the Northeast Landfill Power JointVenture completed construction ofa new gas-to-electricity plant.

Today the facility uses landfill gasto supply as much as 12.3 megawattsof electricity, enough to serve theneeds of about 17,000 homes. Elec-tricity is sold to a local subsidiary ofNew England Power. Rhode IslandSolid Waste Management receivesabout $50,000 per month in royaltiesfor the rights to use the gas.

Lane County stabilizesutility rates

Lane County, OR, also beganexploring the possibility of a gas-to-electricity plant in the 1980s.The resulting facility at the ShortMountain Landfill is a win-winsituation for all concerned.

“The win for us is that we don’thave to develop a gas control pro-ject,” says Mike Turner, manager ofLane County’s solid waste division.“The primary benefit for the entirecommunity is that a resource is notbeing lost.”

Annual gross revenues fromselling steam range from$450,000 to $500,000.

Of this amount, the city ofRaleigh receives annual

royalties of about $70,000.

Revenues from the 1.6-megawattpower plant help stabilize localutility rates. And because the localutility district is consumer-owned,economic benefits are passed di-rectly to its customers.

“With all the rising landfill gasregulations, the county would haveto learn a whole new business if we

Above: Gas produced from decomposinggarbage in landfills is a potential liabilitysoon to come under regulation by the U.S.Environmental Protection Agency. Convert-ing the gas to energy can produce revenuewhile eliminating liability. (Photo courtesy ofDavid Hunter)

Local governments find ways to turn a publicnuisance into the sweet smell of success

LandfillProjectsThat Pay


weren’t here,” says Alan Zelenka, apower resource specialist. “It’s a lotnicer to have someone else do allthis.”

Raleigh generates steamLandfill gas has a medium-Btu rat-

ing. With minimal cleaning, it can beused in conventional boilers to createsteam for industrial processes. Thisis often the most cost-effective use oflandfill gas because it doesn’t requireexpensive equipment such asgenerators.

For example, the city of Raleigh,NC, uses a boiler fueled by landfillgas to generate steam at an averagerate of 24,000 pounds per hour for alocal pharmaceutical company. Gasis collected from the city-ownedWilder’s Grove Landfill. Two privatedevelopers—Natural Power Inc.

and Raleigh Landfill Gas Corp.—invested a total of $1.6 million in theproject. Annual gross revenues fromselling steam range from $450,000 to$500,000. Of this amount, the city ofRaleigh receives annual royalties ofabout $70,000.

“We’ve created an asset out of apotential liability,” says MarshallAshcraft, a budget and managementanalyst with the city manager’soffice. “This is an excellent exampleof public-private partnership.”

Tapping into the potentialCurrently about 100 fully commer-

cial projects in the United States pro-vide electricity and steam for oilrefineries, food-processing plants,brickworks, hotels, hospitals, juniorcolleges, and greenhouses. Yet thisis a mere fraction of the potential

for using landfill-gas-to-energytechnologies. Research now beingconducted by DOE and its industrypartners is aimed at overcomingthe barriers to more widespreadcommercialization.

This article was adapted fromUsing Landfill Gas for Energy: Pro-jects that Pay, a fact sheet in a seriesintended for city and county govern-ments. NREL has produced about 30of these four- to six-page fact sheetsexplaining how local governments canintegrate renewable energy and energyefficiency into their operations. Dollarand energy savings are quantifiedin a case-study format. For moreinformation, contact Bruce Green at(303) 275-3621.♦

How landfill gas toelectricity works

The most common use of landfillgas is to generate on-site electricity.There is little difference between anelectric generating plant using land-fill gas and one using natural gas ordiesel fuel.

Typically, gas is collected by anetwork of vertical wells and hori-zontal shafts strategically locatedthroughout the landfill. Perforatedplastic pipes are inserted into thewells and connected by largerheader pipes that route the gas to acentral processing station. A partialvacuum created by blowers or fans

keeps the gas flowing through thesystem.

After delivery to the centralprocessing station, the gas is filteredto remove particles, condensates,and trace elements. Internal com-bustion engines or gas turbines thenconvert the filtered gas into salableelectricity.

Gas collection

Source: Rhode Island Solid Waste Management Corporation CD-SS25-B013101

Gas processing

Gas filteringand processing

Gas engineor turbine

Electricgenerator

Transformer Utility

Blower

Pipe

Cover dirt

Liner

Landfill

Typical Landfill Gas-to-Electricity Facility

Gravel

Gas wells and collection system

Conversion equipmentInterconnection

with utilities


Biofuels for TransportationNREL/SP-420-5439, DE93000091

America’s vehicles gobble up about two-thirds of all the oil we consumeannually, which is alarming because we now import more than half our oil.Biofuels—fuels produced from agricultural and forestry residues, organicwastes, and energy crops—will help keep America’s wheels rolling, conserveresources, clean up the air, and reduce oil imports. This information packetexplains what biofuels are and describes how NREL is working with indus-try through DOE’s National Biofuels Program to help produce affordablenew transportation fuels.

Biomass Power: Program Overview for FY 1993-1994DOE/GO-10095-089, DE94000241

Did you know that plants and organic wastes can be used to produce elec-tricity as well as transportation fuels? Members of the emerging U.S. biomasspower industry—which employs nearly 70,000 people in more than 1000power plants across the nation—are working with DOE researchers in thenational laboratories to develop or refine the three main biomass powertechnologies: direct combustion, gasification, and pyrolysis. This educational12-page booklet describes recent major achievements and goals for futureresearch and development.

Transmission and Distribution TechnologiesDOE/GO-10095-013, DE95000205

The backbone of the nation’s electricity network is the profusion of wires,transformers, switches, meters, poles, insulators, and other devices thatmake up our transmission and distribution (T&D) system, which must sup-port both the growing demand for electricity and a rapidly changing utilityenvironment. Increased competition, new power generation methods (suchas renewables), and the need for enhanced services are prompting the kindsof innovations described in this informative 20-page overview of the work ofDOE’s T&D Technologies Program.

Benefits & Breakthroughs NewsletterDOE/GO10095-183

Would your company like to improve profits, productivity, and competi-tiveness? Use energy more efficiently? Reduce emissions and pollutants?Or conduct collaborative research and development on new industrial tech-nologies? If so, you’ll want a copy of this new, informative newsletter fromDOE’s Office of Industrial Technologies. It describes current opportunitiesfor collaborative R&D projects and partnership programs that are alreadysaving energy and dollars in some of the nation’s most profitable companies.

These publications are available without charge from NREL’s Document Distribution Serv-ice, 1617 Cole Blvd., Golden, CO 80401-3393, (303) 275-4363, FAX (303) 275-4053.

Publications


Calendar/Technical Reports

NREL-Hosted MeetingsWorld Renewable Energy Congress (WREC)June 15 through June 21; Denver, ColoradoJessica White, (303) 275-4358, FAX (303) 275-4320

National/International MeetingsBuilding Energy—First International Solar Electric Building

Conference, 12th Annual Quality Building Conference, and RENEW ‘96March 4 through March 6; Boston, MassachusettsNortheast Sustainable Energy Association, (413) 774-6051, FAX (413) 774-6053

Thirteenth International Seminar on Primary and Secondary BatteryTechnology and Application

March 4 through March 7; Deerfield Beach, FloridaFlorida Educational Seminars, Inc., (407) 338-8727, FAX (407) 338-6887

7th Annual U.S. Hydrogen Meeting and ExhibitionApril 2 through April 4; Alexandria, VirginiaAngela Barbara, National Hydrogen Association, (202) 223-5547,

FAX (202) 223-5537

Solar 96 National Solar Energy Conference—Sundancin’ in theSmokies

April 13 through April 18; Asheville, North CarolinaAmerican Solar Energy Society, (303) 443-3130, FAX (303) 443-3212

8th Annual American Tour de SolMay 10 through May 17; New York to Washington, D.C.Northeast Sustainable Energy Association, (413) 774-6051, FAX (413) 774-6053

WINDPOWER ‘96: 26th Annual Conference and Exhibition of theAmerican Wind Energy Association

June 23 through June 27; Denver, ColoradoL. Redmond, American Wind Energy Association, (202) 383-2511,

FAX (202) 383-2505

Technical ReportsThe following technical reports pro-

vide technical information on some ofNREL’s research and analysis projects.These reports are available in limitedquantities from NREL’s Document Distri-bution Service at (303) 275-4363 orFAX: (303) 275-4053.

Advanced Hydrogen/Methanol UtilizationTechnology Demonstration. Phase II:Hydrogen Cold Start of a Methanol Vehicle.(May 1995). Work performed by HydrogenConsultants Inc., Littleton, Colorado. Orderno. TP-425-7529; 45 pp.

Crandall, R.; Luft, W. (June 1995).Future of Amorphous Silicon PhotovoltaicTechnology. Order no. TP-411-8019; 26 pp.

Diebold, J.P.; Scahill, J.W.; Czernik, S.;Phillips, S.D.; Feik, C.J. (May 1995). Pro-gress in the Production of Hot-Gas FilteredBiocrude Oil at NREL. Order no. TP-431-7971; 15 pp.

Green, H.J.; Manwell, J. (April 1995).HYBRID2–A Versatile Model of the Perform-ance of Hybrid Power Systems. Order no.TP-441-7807; 12 pp.

Kiss, G.; Kinkead, J.; Raman, M.(March 1995). Building-Integrated Photovol-taics: A Case Study. Work performed byKiss Cathcart Anders Architects, P.C., NewYork. Order no. TP-472-7574; 136 pp.

Osterwald, C.R., Hammond, R.L.;Wood, B.D.; Backus, C.E.; Sears, R.L.;Zerlaut, G.A.; D’Aiello, R.V. (April 1995).Photovoltaic Module Certification/LaboratoryAccreditation Criteria Development.Order no. TP-412-7680; 181 pp.

Potter, T.F.; Lyons, C.E. (March 1995).Next Generation of Automobile EmissionsReduction: Innovative Control of Off-CycleEmissions. Order no. TP-473-7570; 20 pp.

Seventeenth Symposium on Biotechnol-ogy for Fuels and Chemicals: Program andAbstracts of the Symposium, 7–11 May 1995,Vail, Colorado. (1995). Order no. SP-420-7849; 200 pp.

Shipley, D.E.; Miller, M.S.; Robinson, M.C.;Luttges, M.W.; Simms, D.A. (May 1995).Techniques for the Determination of LocalDynamic Pressure and Angle of Attack ona Horizontal-Axis Wind Turbine. Work per-formed by University of Colorado, Boulder,Colorado. Order no. TP-442-7393; 56 pp.

Zweibel, K. (April 1995). Thin Films:Past, Present, Future. Order no. TP-413-7486; 18 pp.


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For more information on work supported by DOE’s Office of Energy Efficiencyand Renewable Energy, contact David M. Blanchfield, Golden Field Office,(303) 275-4797.

DOE’s Office of Energy Efficiency and Renewable Energy is managed byChristine Ervin, Assistant Secretary

Key NREL ContactsTechnical Inquiries: Steve Rubin, (303) 275-4099Technology and Business Ventures: Richard Marczewski, (303) 275-3008Utilities: Gary Nakarado, (303) 275-3072State and Local Governments: Carol Tombari, (303) 275-3057International Programs: Sam Baldwin, (202) 651-7500Media: Kerry Masson, (303) 275-4090Education: Linda Lung, (303) 275-3044

Director’s OfficeCharles F. Gay, Laboratory DirectorBill Marshall, Deputy Director for Operations

Alternative Fuels DivisionCharles Wyman, Director

Analytic Studies DivisionThomas Bath, Director

Basic Sciences DivisionSatyen Deb, Director

Buildings and Energy Systems DivisionSteve Hauser, Director

Industrial Technologies DivisionHelena Chum, Director

Photovoltaics DivisionAnthony Catalano, Director

Wind Technology DivisionRobert Thresher, Director

Washington, D.C., OfficeEldon Boes, Manager

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For address changes and subscriptioninformation, call (303) 275-4363.

Inside this issue:

Advanced wind turbines now on the market — page 3

PV Outdoor Test Facility opens its doors — page 8

Finding NREL on the Internet — page 10

New applications for desiccant cooling — page 12

Empowering America with new energy choices

National Renewable Energy LaboratoryA national laboratory of the U.S. Department of EnergyOperated by Midwest Research Institute

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