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Mitigation Approaches for

Residential Heating and Cooking

10.1 Summary of Key Messages

y In the developed world, residential combustionis a small but potentially important source ofBC emissions. There are clear health benets ofreducing residential wood smoke both indoorsand outdoors. The climate impacts depend onthe relative proportion of OC emissions, locationof emissions (over ice/snow) and the type ofwood-burning appliances used. Upgradingold wood stoves in areas with snow and ice tocleaner-burning appliances (particularly gas-burning) appears to be the most effective strategyto reduce BC and OC from residential woodcombustion (RWC).

U.S. RWC is approximately 3% of the domesticBC emissions inventory. Residential woodsmoke contains PM2.5, air toxic pollutants (e.g.,benzene), CH4, CO2, OC, BC, and BrC.

EPA is currently working to establish new orrevised new source performance standards

(NSPS) for all types of residential woodheaters, including hydronic heaters, furnaces,and wood stoves.

Mitigation strategies for RWC sourceshave generally focused on either replacinginefcient units (wood stoves, hydronicheaters) with newer, cleaner units throughvoluntary or subsidized changeout programs,or retrotting existing units to enable useof alternative fuels such as natural gas(replaces). New EPA-certied wood stoveshave a cost-effectiveness of about $3,600/

ton PM2.5reduced, while gas replace insertsaverage $1,800/ton PM2.5reduced (2010$).

The Arctic Council Task Force on Short-LivedClimate Forcers has identied wood stovesand boilers as a key mitigation opportunityfor Arctic nations. The Task Force hasrecommended countries consider measuressuch as emissions standards, change-outprograms, and retrots to reduce BC fromwood stoves, boilers, and replaces.

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y In the developing world, about 3 billion peopledepend on rudimentary stoves or open resfueled by solid fuels (e.g., wood, dung, coal,charcoal, crop residues) for residential cookingand heating. This number is expected to increasein the coming decades. Cleaner cooking solutionshave the potential to provide huge public healthbenets, and may be particularly important forreducing regional climate impacts in sensitiveregions such as the Hindu Kush-Himalayan-Tibetan region.

According to the WHO, exposure tocookstove emissions leads to an estimated 2million deaths each year; indoor smoke fromsolid fuels ranks as the six largest mortalityrisk factor and the fth largest diseaserisk factor in poor developing countries.Reductions in exposure to these emissionslikely represent the largest public healthopportunity among all the sectors consideredin this report.

The BC climate impacts from cookstovesare likely to be strong in a regional scope,and additional source testing and modelingis needed to clarify the composition ofemissions from these sources and their netclimate impact.

Cookstove mitigation activity today isdifcult to quantify denitively: while theEPA-led Partnership for Clean Indoor Air(PCIA) reported that PCIA Partners soldabout 2.5 million stoves in 2010, it is likelythat 5-10 million improved stoves are sold

each year by commercial entities. In addition,there are no reliable data on the quality orperformance of many of these stoves andthus considerable uncertainty regarding thebenets of their use. The full market of stovesis on the order of 500-800 million homes (3billion people); thus, signicant expansion ofcurrent clean cookstove programs would benecessary to achieve large-scale climate andhealth benets.

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This chapter is divided into two parts. First, itpresents information regarding available mitigationapproaches for residential wood combustion inthe United States and other developed countries.There are a number of cost-effective, advancedmitigation technologies that are well known and

easily deployed; the biggest challenge remainsone of implementation and outreach. The chapterthen examines the technologies and approachesavailable for reducing emissions from the residentialsector in developing countries, where the scale ofthe problem is much broader, the range of sourcesand fuels more complicated, and the challenges toeffective implementation much larger. It describesthe advanced cookstove technologies that arecurrently available and their costs, and considers theemissions reduction potential if these technologieswere adopted on a large scale.

10.3 Residential Wood Combustion inDeveloped CountriesThere are an estimated 29 million wood-burningreplaces, over 12 million wood stoves and hundredsof thousands of hydronic heaters (also known asoutdoor wood boilers) throughout the United States.Emissions from these appliances contain PM2.5,toxic air pollutants, and other pollutants that canadversely impact health and climate. The majorityof these emissions come from old, inefcient woodstoves built before 1990. Wintertime wood smokeemissions contribute to PM2.5nonattainment and

localized problems in many areas in the UnitedStates. For this reason alone, replacing inefcientwood stoves and educating wood burners on properburn practices and stove operation are importantstrategies for reaching domestic air quality goals. Infact, there is far greater certainty about the publichealth benets of reducing residential wood smokeemissions, both indoors and outdoors, than aboutthe net climate impacts, especially in light of the highlevel of OC emissions from these sources.

10.3.1 Emissions from Residential WoodCombustion

Incomplete combustion of wood results in emissionsof ne and ultrane particles, including BC, BrC andother non-light absorbing OC particles. Inorganicmaterials, such as potassium, are also presentin lesser quantities as part of the mix of emittedparticles. In the United States, RWC contributesover 350,000 tons of PM2.5nationwidemostlyduring the winter months. Of this, approximately21,000 tons is BC, which is about 3% of total U.S. BCemissions. The key emitting source categories thatcomprise RWC are wood stoves, manufactured and

masonry replaces, hydronic heaters, and indoorfurnaces. The 2005 PM2.5inventory shows that cordwood stoves contribute about 52%, replaces 16%,hydronic heaters 16%, indoor furnaces 11% andpellet stoves and chimineas (free-standing outdoorreplaces) the remaining 5%. Since 2005, the

popularity and use of outdoor hydronic heaters hasgrown. As a result the emissions from these unitsare growing and are of particular concern to manyareas, like the Northeast and Midwest.

In addition to PM2.5and BC, wood smokecontains toxic air pollutants such as benzeneand formaldehyde, as well as CH4, CO, and CO2.Nationally, RWC accounts for 44% of polycyclicorganic matter (POM) emissions and 62% of the7-polycyclic aromatic hydrocarbons (PAHs), whichare classied as probable human carcinogens.1All of these pollutants are products of incompletecombustion (PIC). These emissions are the directconsequence of poor appliance design andimproper owner operation (e.g., using unseasonedwood) leading to incomplete combustion of the fuel.

OC emissions from RWC generally far exceed theBC emissions, making the OC/BC ratio relativelylarge. However, different wood burning appliancescombust wood in varying ways, resulting in differentOC/BC ratios. In general, wood stoves have lowerOC/BC ratios than replaces (see Figure 10-1), andalso represent a signicantly larger percentage ofthe PM2.5emissions inventory. The type of woodburned also affects the amount of BC and OC

emissions.

Despite the relatively high OC/BC ratio from RWC ingeneral, it is important to consider the location ofthese emissions. While OC emissions are generallyconsidered to have a cooling effect, OC emissionsover areas with snow/ice may be less reectivethan OC over dark surfaces, and may even havea slight warming effect (see Flanner et al., 2007).Signicantly, the vast majority of residential woodsmoke emissions occur during the winter months;the highest percentage of wood stove use is in theupper Midwest (e.g., Michigan), the Northeast (e.g.,

Maine), and the mountainous areas of the PacicNorthwest (e.g., Washington), where snow is presenta good portion of the winter months.

10.3.2 Approaches for ControllingEmissions from RWC

Mitigation of RWC PM2.5emissions generally involvesincreasing the combustion efciency of the source.

1See EPAs 2005 National-Scale Air Toxics Assessment at http://www.epa.gov/nata2005 .

Mitigation Approaches for Residential Heating and Cooking

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Wood burning appliances withlower combustion efcienciestend to have higher emissions ofmost pollutants than do thosewith higher efciencies. Dueto design, conventional wood

stoves, most replaces, andoutdoor hydronic heaters do notburn wood efciently or cleanly.Mitigation strategies for RWCsources have generally focusedon either replacing inefcientunits (such as wood stoves andhydronic heaters) with newer,cleaner units through voluntaryor subsidized changeoutprograms, or retrotting existingunits (such as replaces) toenable use of alternative fuelslike natural gas. The UnitedStates has been working toestablish emissions standardsfor certain RWC sources, but ittakes time for such programsto become effective, as theydepend on the turnover inexisting units. This is discussedmore fully below.

To achieve the cleanest andmost efcient combustion, theappliance needs to reach andmaintain a sufciently high

temperature for all the necessary reactions to occur;adequate time for those reactions; and enoughturbulence to ensure oxygen is available when andwhere it is needed. EPA-certied wood stoves, woodpellet stoves and Phase-2 qualied outdoor wood-red hydronic heaters2are typically designed toincrease temperature in the rebox and to allowfor adequate outside air to mix long enough formore complete combustion. The importance of thecombustion conditions within these home-heatingappliances, and the wood species used as fuel, indetermining the composition of the resulting woodsmoke is reected by the observed variability in

measured OC/BC ratios discussed above.

In general, greater combustion efciency leadsto reductions in the mass of direct PM emissions,including BC, as well as reductions in emissionsof the gas-phase pollutants such as CO, CH4, andthe volatile PAHs. For example, in an EPA studycomparing a New Source Performance Standard(NSPS)-certied wood stove to a traditional zero

2For a list of such appliances, see http://www.epa.gov/burnwise/owhhlist.html.

clearance replace, the total PAH emission factorwas found to be up to twice as high for the replaceas for the more efcient stove burning the same oakfuel (Hays et al., 2003). The same can be observedfor other pollutants depending on appliance type,wood species, moisture content, and so forth.A more efcient appliance also burns less woodfor the same heat output, leading to additionalemissions reductions. However, a recent wood stovechangeout study conducted by the University ofMontana showed signicant reductions in emissionsof OC and levoglucosan (a wood-burning tracer)but little or no change in BC emissions from the

changeout (Ward et al., 2011).

10.3.3 Emissions Standards for New Wood-burning Units

EPA has authority to establish NSPS emissionsstandards for new RWC sources, such as replaces,wood stoves, and hydronic heaters. These standardsestablish manufacturing requirements to limitemissions from new units. Such standards can beupdated over time as new technologies becomeavailable. Since 1988, EPA has regulated PM2.5

Figure 10-1. OC/BC Emission Ratios by Source Category and Fuel Type.(Source: U.S. EPA)

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emissions from new residential wood heaterssold in the United States. The Residential WoodHeaters NSPS (also referred to as the wood stoveNSPS) denes a wood heater as an enclosed, woodburning appliance capable of and intended forspace heating or domestic water heating that meets

specic criteria, including an air-to-fuel ratio in thecombustion chamber averaging less than 35-to-1; ausable rebox volume of less than 0.57 cubic meters(20 cubic feet); a minimum burn rate of less than 5kg/hr (11 lb/hr) tested by at an accredited laboratory;and a maximum weight of 800 kg (1,760 lb). Manytypes of sources are exempt from the existing NSPS,including:

y Wood heaters used solely for research anddevelopment purposes

y Wood heaters manufactured for export (partiallyexempt)

y Coal-only heaters

y Open masonry replaces constructed on site

y Boilers

y Furnaces

y Cookstoves

The Residential Wood Heaters NSPS is unusual inthat it applies to mass-produced consumer items and

compliance for model lines can be certied pre-saleby the manufacturers. A traditional NSPS approachthat imposes emissions standards and then requiresa unit-specic compliance demonstration wouldhave been very costly and inefcient. Therefore, theNSPS was designed to allow manufacturers of woodheaters to avoid having each unit tested by allowing,as an alternative, a certication program that is usedto test representative wood heaters on a modelline basis. Once a model unit is certied, all of theindividual units within the model line are subject tosimilar labeling and operational requirements.

EPA is currently in the process of revising theResidential Wood Heaters NSPS. Specically, theAgency is considering tightening the air pollutionemission limits, adding limits for all pellet stoves,reducing the exemptions, and adding regulations formore source categories, including hydronic heatersand furnaces. EPA expects to propose appropriaterevisions in 2012, and nalize revisions in 2013.The tightening of the wood heater NSPS has thepotential to help reduce future residential woodburning emissions throughout the United States.

10.3.4 Mitigation Opportunities for In-UseRWC Sources

A fundamental limitation of the standards fornew sources discussed above is that they cannotinuence emissions from units that were purchased

prior to establishment of the NSPS. It can take along time for NSPS to actually reduce emissions,depending on the rate of replacement of existingunitsand in many cases, these units can remainin service for decades. Thus, alternative mitigationstrategies are needed to reduce emissions fromexisting sources.

In 2004, a panel convened by the NationalAcademies of Science made severalrecommendations to the EPA for improving airquality management in the United States. One oftheir recommendations was to develop and supportprograms to address residential wood smoke. Since2005, EPA has developed a residential wood smokereduction initiative that has various componentsto support state, local, and tribal communitiesin addressing their wood smoke challenges. Thisinitiative focuses on ensuring that wood burningis as clean and efcient as possible to help reduceemissions of harmful pollutants, the amount of fuelused, and the risk of chimney res from creosotethat builds up due to incomplete combustion. Ingeneral, these programs were developed to reducePM2.5and toxic air pollutants, but can be employedto help reduce BC and other GHG (e.g., CH4andCO2) from RWC. The initiative has the following key

components.

10.3.4.1 Great American Wood Stove ChangeoutProgram

The hearth industry estimates that of the 12 millionwood stoves in U.S. homes today, 75% are woodstoves built before 1990. EPA is working withthe hearth products industry and others to helpstate, local, and tribal agencies create campaignsto promote replacement of old wood stoves andwood-burning replaces with new, cleaner-burningand more energy efcient appliances. Programs vary

from one community to another, with some areasfocusing on changing out old wood stoves andothers on retrotting open replaces with cleanerburning options (e.g., gas stoves). The campaignsare typically led by local government or non-protorganizations at the county or regional level.

Residents of participating communities generallyreceive incentives such as cash rebates, low/nointerest loans and discounts to replace their old,conventional wood stoves and replace insertswith cleaner-burning, more efcient EPA-certied




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gas, pellet, electric, wood stoves and replaces oreven geothermal heat pumps. A new EPA-certiedwood stove, new ue, and professional installationcost, on average, $3,500(2010$). Some areas haveprovided cash incentives tolow-income participants only,while others have providedincentives to everyone in thecommunity. The local agency

leading the replacementprogram will sometimes includeweatherization programs whichinsulate homes to help reduceheat loss and reduce fuelconsumption. Households thatparticipate in these programsare required to surrender theirold wood stoves to be recycled.

Some of the benets ofreplacing inefcient woodstoves include:

y Reduction in PM2.5andtoxic air pollutants (e.g.,benzeno(a)pyrene) by 70%

y Reduction in indoor PM2.5emissions by 70% accordingto University of Montana3

3For more information, see: http://www.ncbi.nlm.nih.gov/pubmed/18665872.

y Improvement in energy efciency by 50%, usingone-third less wood

y Reduction in CH4, BC, and CO2from improvedcombustion efciency and use of less fuel wood.

A variety of examples of state and local efforts toreduce emissions from older appliances are availableat EPAs Burn Wise website: http://www.epa.gov/burnwise/casestudies.html.

EPAs wood stove changeout effort has focusedprimarily on counties at or near nonattainmentfor PM2.5where wood smoke is an important localsource. EPA estimates that through 2011, the GreatAmerican Woodstove Changeout Program hashelped changeout or retrot nearly 24,000 woodstoves and replaces in 50 areas. From 2010 on, thisprogram is anticipated to reduce approximately370 tons of PM2.5and 63 tons of hazardous airpollutants (HAPs) each year after 2010, providingapproximately $120 million to $330 million (2010$) inestimated health benets in the U.S.4

The best available cost-effectiveness information onresidential wood smoke mitigation comes from a

4These estimates reect national average benet-per-ton estimatesfor directly emitted carbonaceous particles from area sources fromhttp://www.epa.gov/air/benmap/bpt.html (data accessed February2011) and Fann, Fulcher, Hubbell 2009 methodology. Theseestimates have been inated from 2006$ to 2010$.

New Wood Stoves andPollution Reduction

EPA estimates that every 1,000 old wood stoveschanged out to cleaner burning hearth appliances willresult in annual pollution reductions of

y 815 tons of CO2

y 53 tons of CH4

y 27 tons of PM2.5

y 4 tons of toxic pollutants

y 14 tons of OC

y 1.6 tons of BC

(Numbers generated using EPAs Wood Stove andFireplace emissions calculator: http://www.epa.gov/burnwise/resources.htmland EPAs speciation profile database.)

Figure 10-2. Cost Per Ton PM2.5Reduced for Replacing Non-EPA-Certified Wood Stove with EPA-Certified Woodstove (in 2010$).(Source: U.S. EPA, based on data from http://www.marama.org/visibility/ResWoodCombustion/RWC_FinalReport_121906.pdf)

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Mid-Atlantic Regional Air Management Association(MARAMA) document called Control Analysis andDocumentation for Residential Wood Combustion inthe MANE-VU Region (2006). This document focusedon the costs of total PM2.5mitigation. The resultssuggest that the cost per ton of PM2.5emissionsreduced from wood stove changeouts and replaceretrots is similar to the cost of other PM2.5controls

discussed in previous chapters of this report.Figures 10-2 and 10-3 summarize the MARAMAestimates of the cost per ton PM2.5reduced fromthese measures; these costs vary depending on thetype of wood burning appliance being replaced(old wood stove vs. open replace) and on thereplacement technology (e.g., EPA-certied woodstove vs. wood pellet stove).

10.3.4.2 Outdoor Wood-Fired Hydronic HeaterProgram

In 2007, EPA initiated a partnership to reduce

emissions from new outdoor wood-red hydronicheaters. This program is aimed largely at areaswith PM2.5air quality problems. EPA has workedwith industry to reach agreement on voluntaryperformance levels for new heaters to bring them tomarket faster than feasible under regulation. Similarto the wood stove changeout program, there arepotential climate change, air quality, and energyefciency benets with this program. The programis structured in two phases: under Phase 1, qualiednew units were 70 % cleaner than existing units and,under Phase 2, which began in October 2008, new

units are required to be 90%cleaner than existing units.5EPAhas now expanded the programto include indoor models andhydronic heaters that are fueledby other kinds of solid biomass

(e.g., wood pellets).As of 2011, nearly 10,000EPA-qualied units had beensold; 24 manufacturing partnershad agreed to produce units70%-90% cleaner; and 22models had been placed on themarket, reducing approximately6,100 tons of PM2.5emissionseach year after 2011 andproviding approximately $2.2billion to $5.4 billion (2010$) inestimated health benets in theU.S.6

10.3.4.3 New ConstructionWood-Burning FireplaceProgram

The EPA voluntary Wood-burning Fireplace Programis modeled after the Hydronic Heater Programand helps reduce wood smoke emissions growthin areas with PM2.5air-quality problems. The two-phase program covers new installation of low mass(i.e., pre-manufactured) and masonry replaces,and is expected to drive technology improvements

much sooner than possible through regulation.The program qualies models achieving a Phase 1(34% reduction) or a Phase 2 (54% reduction) PM2.5emission level. EPA has worked closely with thehearth products industry to develop this program;however, growth in the program has been hamperedby the slowdown in new home construction in theUnited States.

10.3.5 Additional Regulatory Approaches toLimiting Wood Smoke Emissions

A variety of regulatory programs, including wood

burning curtailment programs and requirementsto remove old stoves upon resale of a home, haveproven effective in helping to address wood smoke.

5Use of Phase 1 labels was prohibited after March 31, 2010. Seehttp://www.epa.gov/burnwise/owhhlist.html .

6These estimates reect national average benet-per-ton estimatesfor directly emitted carbonaceous particles from area sources fromhttp://www.epa.gov/air/benmap/bpt.html (data accessed February2011) and Fann, Fulcher, Hubbell 2009 methodology. Theseestimates have been inated from 2006$ to 2010$.

Figure 10-3. Cost Per Ton PM2.5Reduced ($/Ton) for the Addition of anInsert into a Fireplace (2010$). (Source: U.S. EPA, data courtesy of MARAMA)


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replaces. It also notes the upcoming wood heaterNSPS has the potential to help reduce futureresidential wood burning emission throughout theUnited States. Several state and local communitieshave effectively implemented residential woodsmoke control strategies and have signicantly

reduced harmful wood smoke pollution. For example,Lincoln County, MT and Sacramento MetropolitanAir Quality Management District have encouragedcomprehensive wood smoke reduction strategiesto help these areas clean the air and protect publichealth.

10.4 Residential Cookstoves inDeveloping CountriesMore than 3 billion people worldwide cook theirfood or heat their homes by burning biomass(e.g., wood, dung, crop residues, and charcoal) orcoal in polluting and inefcient traditional stoves(International Energy Agency, 2010). As discussedin Chapter 4, BC emissions from these sources areestimated to account for 21% of the total globalinventory. This use of solid fuels also representsa signicant part of energy use in developingregionsincluding nearly 50% of total primaryenergy supply in Africa, and about 27% in India(International Energy Agency, 2009). Use of biomassand waste in developing nationsnearly all of whichis for household cooking and heatingaccountsfor about 60% of global renewable energy use(International Energy Agency, 2009, Annex A). About

82% of those who rely on traditional biomass fuelsfor cooking live in rural areas; however, in Sub-Saharan Africa, nearly 60% of people living in urbanareas also rely on biomass (International EnergyAgency, 2010).

As discussed in Chapter 3, several decades ofresearch document the signicant risks to publichealth associated with traditional cookstoves.Exposure to cookstove emissions leads to anestimated 2 million deaths each year and ranks as thesixth highest mortality risk factor and fth highestdisease risk factor overall (in terms of disability

adjusted life yearsDALYs) in poor developingcountries (World Health Organization, 2009).Emissions from cookstove use have been linked toadverse respiratory, cardiovascular, and neonataloutcomes and to cancer (Smith et al., 2004). Of thetotal global mortality associated with exposure tocookstove smoke, Sub-Saharan Africa, China andIndia each account for approximately 25-30%, withthe remainder of deaths attributable to cookstovesoccurring elsewhere in Asia and Latin America.

The contribution of this source category toemissions of BC and other aerosols has been thefocus of growing interest, especially in terms ofimpacts on sensitive regions such as the Himalayas.A recent study on BC emissions from cookstovesin northern India indicated that cooking with solid

fuels is a major source of ambient BC in the region,with peak ambient BC concentrations of about 100g/m3(Rehman et al., 2011). Furthermore, the studyindicated that OC concentrations (which exceededBC concentrations by a factor of ve) containedsignicant absorbing BrC, and suggested thatprevious estimates of atmospheric solar heatingin the region due to particles from cookstoveemissions should be increased by a factor of two ormore. However, there remains signicant uncertaintyabout the extent of BC and associated emissionsfrom cookstoves, and the effect of those emissionson climate. Given the complex emissions mixtureresulting from cookstove use, further study isneeded to pinpoint the most benecial strategiesfor reducing BC emissions from this source.Unquestionably, however, this sector represents thearea of largest potential public health benet of anyof the sectors considered in this report. Mitigationof emissions from cookstoves offers a tremendousopportunity to protect health, improve livelihoods,and promote economic developmentparticularlyfor women and children. For this reason alone,irrespective of the additional climate benets thatmay potentially be achieved, mitigation of cookstoveemissions is a pressing priority.

Mitigating BC emissions from cookstoves dependsrst on identifying technologies that are proveneffective in reducing BC emissions, and secondon encouraging adoption of these technologieson a large scale. As discussed below, very fewimproved stoves have been designed specicallyto reduce BC emissions, and while some improvedtechnologies are emerging, no advanced stovesthat burn solid fuel have yet been adopted ona broad scale (though LPG has been widelydisseminated as a clean cooking fuel, and China(see below) implemented a very large earlier stovesprogram using intermediate stoves). The problem

is complicated by the fact that both the impactsof cookstoves and the solutions are regionallydependent. Specically, the extent of achievableBC reductions, and the impact of those reductions,will depend on the type of stove, the type of fuelused, and the location of emissions. Improvedcookstoves and fuels must satisfy the needs of localusers, enabling them to cook local foods at thetime and in the manner they prefer, using the fuelsthat are available and affordable. Given the array ofdifferent technologies and fuels currently in use, andthe sheer number of sources involved, mitigation




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of BC emissions from cookstoves represents anenormous challenge. However, given their signicantcontribution to the global inventory of emissions,and the increasing availability of cost-effectiveand locally appropriate solutions and several otherfactors noted in section 10.4.3, this sector represents

one of the most promising opportunities formitigation of BC internationally.

10.4.1 Emissions from Cookstoves

Currently, residential cookstoves contributeapproximately 21% of the global BC emissionsinventory, with emissions concentrated in Sub-Saharan Africa, China, India, and other developingregions of Asia. Dependence on traditional biomassfuels is highly correlated with poverty; countries withhigher household income also tend to have a highershare of modern fuels for residential consumption.While the percentage of people relying on traditionalbiomass fuels for basic household energy needs isexpected to decrease in most areas over the comingdecades, the aggregate number of people relyingon biomass for cooking and heating is expectedto increase by 100 million people by 2030 due topopulation growth (International Energy Agency,2010). IEA projects that the fastest shift towardmodern fuels will occur in India, and the slowest shiftwill occur in Sub-Saharan Africa (International EnergyAgency, 2010). The impact of these changes onemissions is still unclear: as discussed in Chapter 7,under most scenarios, residential emissions areprojected to decline signicantly by 2030 and further

still by 2050 (Streets et al., 2004). However, a declinein emissions, and the rate of decline will dependon rates of adoption of cleaner fuels and cookingtechnologies described below, and some regionsmay experience near-term increases in emissions.

10.4.2 Technologies and Approaches forControlling Emissions from Cookstoves

Because cooking is such a variable, individual-specic activity, there are many complexitiesrelated to achieving reductions in BC emissionsfrom improved cookstoves. The type of fuel and its

moisture content, the type of stove, the purposefor which it is used (heating vs. cooking), and themanner in which the stove is tended all affectcomposition of emissions (MacCarty et al., 2008).Cooking practices vary both daily and seasonally dueto variation in available foods and fuels, and variationin fuel quality. Additionally, there may be signicantvariation in the efciency and durability of stoves,even those that are mass produced.

There is currently no formal denition of whatconstitutes an improved stove. In the past,

improved stoves typically meant low-cost, locallymade stoves aimed at improving efciency andreducing fuel use. A primary motivation for theuse of improved stoves was to reduce demand forfuel wood, thereby reducing pressures on forestsas well as the time spent by women and children

gathering fuel (Graham et al., 2005; Partnership forClean Indoor Air, 2005). However, not all such stovesfunctioned as intended. For example, stoves thathave a large amount of heated mass, such as theLorena stove, may remove smoke with a chimney,prevent burns, and help warm a house, but may notsave fuel compared with an open re (USAID, 2007).

Over the last ten years, a new suite of more effectivestoves has been introduced to the marketplace. Asa group, these new improved stoves are designedto be much more efcient and clean (as well assafe), and utilize a variety of different technologiesand fuels. Most are produced locally for thenearby market, while there are a few that are massproduced internationally and can be shippedanywhere in the world. The stoves span a widerange of cost, durability, and performance, andare designed for different types of staple foods.Importantly, however, these stoves are generallydesigned to reduce fuel use and emissions ofPM2.5and CO (as proxies for the broader suite ofemissions from these stoves). Few of the stovescurrently on the market were designed to reduceBC specically (the new Turbococina stove is anexception). In laboratory settings, most of thesestoves achieve PM2.5reductions of 40% to 70%.

Results from MacCarty et al. (2008) indicate thatsome non-advanced stoves may not substantiallyreduce BC emissions, but some gasier and forceddraft (or fan) stoves signicantly reduce BCemissions compared to the open re. Field testinghas begun to determine whether stoves performas well in actual (real-world) conditions as in thelaboratory. Results from eld tests indicate thatstove performance under actual conditions varies(Roden et al., 2009; USAID, 2011). Much more suchtesting is needed, as well as additional research anddevelopment in stove design to determine if thestoves are reducing BC in addition to total PM2.5.

Among the new technologies now emerging onthe cookstove market, there are a few advancedsolutions that have been shown to reduce PM2.5by 90% or more in laboratory settings; the limitedlab testing performed on these stoves to dateindicates that some stoves reduce BC by a similarpercentage (MacCarty et al., 2008). These newtechnologies include advanced forced-draft stovesand gasier stoves (Roth, 2011) that use varioussolid biomass fuels (including wood, pellets, cropresidues, etc.); biogas stoves; and liquid-fuel stoves

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that burn ethanol, plant oil, or other biomass fuels.It is important to note, however, that few of thesestoves are widely commercially available and theirperformance in the eld has not been fully evaluated.

Some stoves require electricity to drive a fan (seeFigure 10-4), while others have been designed toconvert waste heat to electricity to power a fan,which enables excellent emissions performance(including BC emissions reductions) without theneed for access to electricity (see Figure 10-5).9Some of these stoves are being further tested foremissions in both the lab and the eld. These newstove technologies have the potential to reduceemissions from cookstoves nearly to the levels ofclean fuels such as LPG (Wilkinson et al., 2009), butmany (though not all) require specic and/or highlyprocessed fuels, which increases the total cost of

use (Venkataraman et al., 2010). In some cases, cleanfuels (ethanol, biogas) are not widely commerciallyavailable for cooking. Forced-draft stoves that donot generate their own electricity require access toanother electricity source, which can be costly. Evenbattery-powered fan stoves require intermittent

9These stoves may also soon be able to reliably generate enoughelectricity to be used for other purposes (e.g., lights or cell phones),which could increase consumer demand. The change in emissionswith the new stove would depend in part on the extent to whichoverall stove usage increased due to demand for these extraservices (Venkataraman et al., 2010).

access to electricity. Some gasier stove designs usenatural draft (natural convection) and do not requirea fan.

While the basic outlines of lab and eld tests havebeen in place for decades, it is only in the past ve

years that organizations funding household energyinterventions have begun requiring emissionspre-testing, or that performance benchmarks(even informal ones) have been established.Recent testing in both lab and eld settings (seebelow) demonstrate that this new generation ofstoves is achieving real and measurable results.Developing globally recognized standards that arewidely accepted by the cookstove community andadopted by country governments could spur widerdevelopment of clean cookstoves.

Based on available performance and cost data,currently available technologies exhibit a wide rangeof performance. These options include:

y electric stoves

y gas and liquid fuels

y processed solid fuels

y advanced biomass stoves

y rocket stoves

Figure 10-4. The Turbococina Stove, which burns wood,

is made of a stainless steel cylinder fitted with 10 airinjectors, an internal fan that runs on electricity, and a steelplate that regulates the air flow to improve combustionefficiency. This stove is currently available primarily forinstitutional settings. (Photo courtesy of Ren NuezSurez, Turbococina)

Figure 10-5. Woman Prepares Banku on a BioLiteHomeStove in Kintampo, Ghana. BioLite stoves converttheir waste heat into electricity, which is used to powerthe fan and can be used to charge a battery for a mobilephone (as shown in photo), LED light, or other low-powerpurpose. (Photo courtesy of Jonathan Cedar, Biolite)




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y simple stoves

y solar cookers

y behavioral and structural solutions

10.4.2.1 Electric StovesCooking with electricity produces zero emissionswithin a household, and therefore is highly effectiveat reducing personal exposures of stove users.However, from a broader public health or climateperspective, emissions associated with the increasein power production must also be considered. Theongoing electricity costs for these stoves can varysubstantially by region.

10.4.2.2 Gas and Liquid Fuels

Switching from solid fuels to gaseous or liquid fuelsis often the easiest means of dramatically loweringemissions from cooking. In laboratory testing, theAprovecho Research Center (Aprovecho) foundthat using liquid petroleum gas (LPG) decreasedthe amount of energy used by 69%, the mass of

fuel used by 89%, particle emissions by over 99%,CO emissions by 98%, and time to boil by 40%, ascompared to cooking over an open re (MacCartyet al., 2010). Field research in Guatemala showedthat LPG stoves could reduce indoor 24-hr PM2.5concentrations by over 90% (Naeher et al., 2000).

Liquid fuels such as ethanol, kerosene, and plant oilsare also options (see Figure 10-6). Aprovechos labtests found that cooking with well-made ethanol orkerosene stoves decreased the mass of fuel used by75% and 82% respectively and particle emissions byover 99% for each; CO emissions by 92% and 87%(MacCarty et al., 2010).

Biogas derived from waste biomass is potentially asclean as LPG, and in addition it is renewably derived(reducing CO2impacts) and requires no distributioninfrastructure. Emissions testing of biogas stoves todate suggests that these stoves perform signicantlybetter than solid fuel/stove combinations withregard to emissions of methane, CO, VOC, and CO2(Smith et al., 2000b). Plant oils are another liquidfuel being used today for cooking, but independenttesting results for stoves using these fuels have notyet been published. Stoves using gas and liquidfuels involve an upfront cost of $5 to $50 per stove,as well as an ongoing cost for the fuel that variessubstantially by region, fuel, and changing economicconditions. LPG stoves can also require signicantdeposits on the cylinders, another serious barrierfor the very poor. It is also important to note thatpoorly made kerosene stoves in particular posesafety concerns, including the potential for severe

burns and injury associated with accidental res(Peck et al., 2008).

10.4.2.3 Processed Solid Fuels

For much of the developing world, the advancedsolutions described above may be unavailable orsimply too costly to use in the near-term. Stovesutilizing processed solid fuels in the form ofcharcoal, pellets, prepared wood, and briquettes,may be more accessible, and these can alsorepresent very clean solutions. However, like theclean fuels noted above, using processed fuels also

involves an ongoing operating cost, which mayserve as a barrier for these solutions, especiallyin regions where fuel wood can be collectedfree of charge. However, in markets where fuelis purchased, stoves that increase combustionefciency by 50% are often the easiest stoves tomarket, since the consumer can expect a quickpayback period on the initial investment.

Charcoal is the most common processed solid fuelused today. A number of charcoal stove modelsare available (see Figure 10-7). Lab tests of charcoal

Figure 10-6. CleanCook Ethanol Stove. Currentlythese stoves are being deployed in refugee camps inEthiopia and Kenya, with over 3,800 stoves already in use.Deployment of additional stoves is dependent partly onthe availability of ethanol. (Photo courtesy of Harry Stokes,Project Gaia)

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stoves for climate forcing emissions found that thesestovesrelative to an open rereduced the BC/

OC ratio somewhat, and reduced total particlesby about two thirds (MacCarty et al., 2008). It isimportant to note that the laboratory emissionstests do not account for emissions in the charcoalproduction process, which is highly inefcient andpolluting, with signicant net climate impacts (Bailiset al., 2005). Aprovecho has tested many charcoalstoves for PM2.5, CO, and fuel use, nding that PM2.5emissions were 90% lower than for a 3-stone reand fuel use savings ranged from 45% to 65%.Most charcoal stoves cut time to boil, though onlymodestly. However, CO emissions increased for allstoves except one (MacCarty et al., 2010). In 2007,

EPA tested two charcoal stoves and found thatrelative to a 3-stone re, PM2.5emissions from thecharcoal stoves fell by over 90% from a hot startbut increased when operated from a raw, cold start,and both stoves increased CO emissions (Jetter andKariher, 2008).

Creating pellets from biomass or briquettes fromeither coal or biomass can lead to substantialimprovements in efciency and emissions whenpellets are burned in well-designed stoves. TheOorja stove (developed by BP and now owned by

First Energy of India) is an example of a very clean-burning pellet stovein this case the pellets are

made from crop residues by a partner company.More than 400,000 Oorja stoves have been soldand between 250,000 and 350,000 are in use everyday. However, given the cost of pellets, this stovecompetes with LPG. Other examples include project-based work that have developed briquettes fromwaste biomass (Haiti, Ghana, and Uganda), stovesdesigned to burn pellets made from locally availablewaste biomass (West Africa and elsewhere), and astove that burns rice hulls (Philippines), though EPAis not aware of any examples where this work hasbeen carried to a large scale. With regard to coalcooking, laboratory measurements indicate that

the combination of using improved stoves withprocessed coal briquettes could have a dramaticimpact on aerosol emissions. Zhi et al. measuredreductions in particles of 63%with OC decreasing61% and BC decreasing 98%. This reduced the BC/OC ratio by about 97%, from 0.49 to 0.016 (Zhi et al.,2009).

10.4.2.4 Advanced Biomass Stoves

There are two types of advanced biomass stovesthat can achieve high levels of performance: forced

Figure 10-7. Charcoal Stoves. (a) Charcoal Stove by Burn Design. (Photo courtesy of Peter Scott, BurnDesign) (b) Charcoal Zoom Versa Stove produced by EcoZoom. (Photo courtesy of Ben West, EcoZoom) (c)Prakti Charcoal Stove. (Photo courtesy of Mouhsine Serrar, Prakti Design) (d) Envirofit CH-4400 CharcoalStove. (Photo courtesy of Envirofit) (e) Toyola Charcoal Stove in use in a village in Ghana. (Photo courtesy ofSuraj Wahab, Toyola Energy)

(a) (b) (c)

(d) (e)




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draft and gasier stoves. Gasier stoves can beforced-draft or natural draft. These stoves can burnprocessed or raw biomass, though it is likely the case(eld testing data forthcoming) that those usingprocessed fuels will perform better in the eld, sinceprocessed fuels eliminate a major variable in real-world use of the stoves. It is also likely that lab andeld emissions test results will be more consistent

for stoves that burn processed fuels. Lab testing ofadvanced biomass stoves to date generally conrmsthat these advanced biomass stoves can achieveremarkable emissions reductionsup to 93%lower than traditional stoves (Venkataraman et al.,2010). One study found that these stoves achievedsubstantial reductions in both overall particlesand BC specically, with the fan stove signicantlyreducing particle emissions and the gasier stovesreducing total particles by about two-thirds (as wellas reducing the BC:OC ratio). The study also showedthat the fan stove was able to reduce time to boil, atleast under the lab conditions (MacCarty et al., 2008).

Under Aprovechos broader lab testing, forced draftfan stoves all reduced (relative to a 3-stone re) fueluse (by 37% to 63%), CO emissions (in all cases byover 85%), PM2.5emissions (from 82-98+%), and timeto boil (11% to 65%). Similarly, the gasier stovestested by Aprovecho saved on fuel use, reducedCO emissions, achieved dramatic reductions inparticle emissions (with one exception), and cutthe time to boil, though generally all to a lesserextent than the fan stoves (MacCarty et al., 2010).In EPAs 2007 testing, the one advanced fan stove

tested (Philips) had the best overall performanceand the lowest pollutant emissions, reducingemissions of key pollutants such as PM2.5and COby about 90%. Notably, of the wood burning stovestested, this stove was also the one that requiredthe least attention to operate (Jetter and Kariher,

2008), although it required fuel with short (


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reduce time to boil, though to a lesser extent than anadvanced fan stove.

Aprovecho tested a wide variety of rocket stoves andfound important variability in performance indicatingthat design is critical. Most saved signicantly (butnot equally) on fuel use (26% to 51% savings relativeto a 3-stone re), though two failed to cut fuel use.All rocket stoves cut CO emissions by 70% or more,while performance on PM2.5emissions varied muchmore widely (one actually increased emissions), with

60% of those tested achieving reductions of over50%. Some of the rocket stoves actually increasedthe time to boil, though most cut it modestly(MacCarty et al., 2010). In EPAs 2007 testing, severalnon-advanced wood stoves were tested and resultsvaried depending on the design and the stage ofoperation. Generally, emissions were lower than the3-stone re, with faster times to boil. For example,the UCODEA wood stovenow called Ugastovereduced PM2.5and CO emissions by 48% to 65%when operated at high power, and 35% to 50% atlow power (Jetter and Kariher, 2008).

The U.S. Agency for International Development(USAID) recently conducted extensive eld testingof ve non-advanced biomass stoves in the Dadaabrefugee settlements in Kenya. They tested for fueluse, time to boil, and several user preferencesbutdid not test for BC or any other emissionsandconcluded that all ve tested stoves outperformedthe open re, requiring signicantly less fuel tocook the test meal....with savings ranging from32% to 65 (USAID, 2010b). Additional testing oftwo manufactured rocket stoves by ColumbiaUniversity researchers demonstrated substantial and

statistically signicant fuel savings relative to thethree-stone re (38% and 46% on average, for thetwo stoves), but further stressed that fuel savings isjust one factor that affects suitability of any givenstove in a particular community. Other relevantfactors include stove size, ease of use, and cookingtime (Adkins et al., 2010).

USAID (2011) also completed a recent round ofcookstove testing in the eld in Uganda that didexamine BC and other emissions and factors,

comparing a traditional stove to a leading rocketstove. The study found that with the greater fuelefciency of the rocket stove (42% savings weremeasured) came lesser emissions of PM4.0andcarbon monoxide. However, the rocket stove (whichwas not designed to reduce BC emissions) hadmore than twice the fractional BC content in its PMemissions (15.5%) compared to the traditional stove(7.2%).

Recent eld testing in India (Kar et al., 2012) notedabove found preliminary results showing that thenatural draft stoves had much wider variation in

performance than the forced draft stoves, and didnot achieve nearly as great reductions in BC. Forexample, these natural draft stoves reduced BCemissions in the breathing zone by a factor of 1.5on average (22% to 55%), as compared to a factorof 4 for forced draft stoves. However, BC reductionsvaried signicantly among natural draft stoves:only micro-gasication stoves were shown by Karet al. (2012) to be effective in reducing BC, whileother models occasionally emitted more BC than atraditional cookstove. BC emissions were shown tovary signicantly among cooking cycles with same

Figure 10-9. Rocket Stoves. (a) Envirofit G3300 Biomass Cookstove in Use in Tanzania. (Photo courtesyof Nancy Ryden, Envirofit) (b) Zoom Dura Biomass Cookstove produced by EcoZoom. (Photo courtesy ofEcoZoom)

(b)(a)




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stove, and the use of mixed fuel(reective of local practices) wasshown to increase plume zone BCconcentration (compared to hardwood) by a factor of 2 to 3 acrossthe stoves tested.

Several studies have measuredchanges in indoor concentrationsof PM2.5(but not BC) in kitchensin Latin America due to thetransition from a traditionalopen re to the use of a griddlestove (known in Latin Americaas aplanchastove)a raisedwood-burning stove with achimney, typically designed witha at griddle to make tortillas.Naeher et al. (2000) reportedreductions in 24-hour PM2.5concentrations of over 80%, andreported earlier measurementsthat achieved reductions rangingfrom 57% to 82%. (See Figure 10-10 for a picture ofan improved wood-burning stove with a chimney.)Masera et al. found that CO and PM2.5concentrationsin the kitchens using a so-called Patsaristove werereduced by 66% and 67%, respectively, comparedto traditional cooking methods (Masera et al., 2007).Johnson et al. (2007) further reported that whilePatsaristoves reduce overall particulate emissions inhomes (including net BC emissions), the BC/OC ratiowent up, making the net warming implication more

ambiguous. McCracken et al. measured personalexposures (always less than reductions in indoor airconcentrations since individuals do not spend allof their time in kitchens) and reported reductionsin daily average exposure to PM2.5of over 60%(McCracken et al., 2007).

These stoves typically cost anywhere from $8-$100per unit, depending on the design, quality ofmaterials, performance, use of a chimney, use of ametallicplancha(for making tortillas), and durability.Certain models of these stoves have combustionchambers that might also be used to build quality-

controlled mud stovesthe combustion chambersthemselves may cost as little as $4 to produce.

10.4.2.6 Simple Stoves

Aprovecho test results for a wide variety ofsimple stoves without a rocket or other improvedcombustion chamber indicated that the performanceof these stoves varies enormously, with only twoof seven tested achieving meaningful emissionsand fuels use reductions. Most achieved some fuelsavings, but increased particle emissions (MacCarty

et al., 2010). These stoves typically cost only$2 to $10 per unit, but may last only a few monthsdue to use of less durable materials and lowerquality construction.

10.4.2.7 Solar Cookers

Solar cookstoves are emissions free, and thusthe cleanest solution. However, the constraints ofcurrent solar cookers are signicant: they have

limited use in the early morning, late afternoon, oron cloudy or rainy days; they can greatly increasecooking time; and they are not suitable for cookingmany foods. For this reason, the potential forcurrent solar cookers is best thought of as partof an integrated solution. EPA is not aware of anyexample of solar cookers (which range in cost from$20 to $75 per stove, including the pot) beingadopted at a large scale in a given region. However,with additional advances, such as improvements inenergy storage capacity, it is conceivable that solarstoves could be an effective tool for this eld in thefuture.

10.4.2.8 Behavioral and Structural Solutions

Many behavioral and structural steps can be takento reduce human exposures to cookstove smoke.These include cooking outdoors, keeping childrenaway from cooking stoves, adding ventilation tothe kitchen, preparing fuel (drying and cutting to asmaller size), tending stoves more carefully, lightingstoves with improved techniques, or requiringstoves to have chimneys. Each of these solutionswill diminish immediate human exposures to

Figure 10-10. Prakti Double-Pot Woodstove with Chimney. (Photocourtesy of Mouhsine Serrar, Prakti Design)

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500 partners, PCIA indicates that partners sold2.5 million stoves in 2010 (see Figure 10-11). Basedon the latest survey results, PCIA Partners are more

than doubling their stove sales every other year.This does not include the internal Chinese stovemarket and independent manufacturers that makeand sell different versions of the so-called Jikocharcoal stove across Africa. Including these sales,the total number could be as high as 5 million to 10million stoves per year, though there is not reliableinternational data on the quality or performanceof many of these stoves, limiting the assessment ofclimate and health benets. Despite this progress,the total impact of the cookstove replacementsto date has been small, given that the total stovemarket is on the order of 500 million to 800 million

homes.

In addition to the design and fuel innovations notedabove, a number of recent developments point toa much greater potential for making large-scaleprogress in the cookstove sector. These include:

y Growth of Existing Businesses and BusinessModels:An increasing number of businesses aremanufacturing and/or selling improved stovesand fuels, utilizing a wide range of businessmodels. These models include non-governmental

organizations (NGOs) working to catalyze localbusinesses around a common and tested stovedesign (e.g., GERES Cambodias local partnersjust sold their 1.5-millionth stove); workingto develop local businesses to make and sellartisanal stoves (e.g. GIZs global efforts to

provide over 4 million homes with improvedstoves over the past 5 years); a local factoryselling directly (e.g., HELPS/Guatemala hasgrown rapidly and sold over 100,000 stoves);international manufactures with local distributors(e.g., a partnership between the AprovechoResearch Center in Oregon on design, ShengzhouStove Manufactures in China, and Colorado-based EnviroFit International on sales); and majorcorporations building their business in emergingmarkets (e.g., Philips, Bosch-Siemens).

y New Scalable Technologies: Many of the stovesnoted above represent a new suite of stovetechnologies that are well designed and durable,and for which extensive emissions testing hasbeen conducted. Such stoves could be massproduced, which would improve the scalability ofthese solutions (Venkataraman et al., 2010).

y Carbon Financing: Cookstove businesses areincreasingly leveraging carbon nancing inboth the formal and voluntary markets toprovide capital and increase public awareness.The nancing arrangements vary substantially,but typically yield about 0.5 to 2 tons of CO2-equivalents per stove per year for improved wood

and charcoal stoves, and up to 3 to 5 tons of CO2-equivalents per stove per year for improved coalstoves. Importantly, however, these credits arebased on GHG (mostly CO2) emissions reductions,as measured by reductions in fuel use duringin-eld tests. Additional work would be requiredto establish credits for BC reductions. Carbonnancing is already transforming nancing ofcookstove efforts into more rigorous nancialtransactions with rigor and accountability forstoves sold, stove performance in the eld, andstove utilization over time. The high transactionscosts involved in obtaining project approval also

incentivize large-scale projects and encouragethe continued use of approved stoves for manyyears to generate ongoing credits. Impactinvesting is a separate, but important opportunityto bring social capital investments to thiseld, and examples of this tool applied to thecookstove eld are beginning to emerge.

y New Testing and Monitoring Tools: The demandfor rigorous monitoring for carbon and othernancing, research, and other needs has also ledto the development of less expensive and more

Figure 10-11. Number of Improved Stoves Sold by PCIAPartners, 2003-2010. (Source: U.S. EPA)

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effective monitoring technologies that greatlyimprove our ability to measure and interpreteld results. These include relatively inexpensivePM2.5monitors, BC monitors, personal exposuremonitors for CO and PM2.5, portable stoveemissions testing hoods, stove use monitors, and

cell-phone based wireless monitoring tools.In spite of this progress, achieving large-scaleadoption of clean cooking solutions will not be easy,and many remaining barriers must be addressed.A recent World Bank study has summarized someof the key challenges, emphasizing the need fora range of stoves that meet users needs, withdemonstrated ability to reduce fuel use and indoorsmoke, while maintaining durability and safety.The report also notes that successful programsrequire functioning commercial markets in orderto reach and maintain a large scale of successglobally. Innovative nancing techniques and well-constructed monitoring and evaluation programswere other tools highlighted as critical to success inreaching the poor (World Bank, 2010). Other majorconsiderations include:

y Institutional Barriers: Such barriers include thelack of accepted international standards fordifferent stove-fuel combinations, the lack ofindependent stove testing facilities in marketplaces around the world, and the lack of healthguidelines regarding what interim targets onwhat is considered a clean stove.

y Cost: The cost of improved stoves and fuelsalone pose a major challenge for manyhouseholds. Additional nancial barriers includetariffs and duties to import stoves, the largeinvestment needed to take a prototype stoveto mass production, the cost and difculty ofdeveloping distribution chains in target markets,the high transactional costs of carbon nancing,and the costs of managing an inventory for awidely uctuating market during business start-up. Separate nancing tools are needed makeadvanced stoves affordable for the poorestpopulations.

y Social Barriers: Cooking solutions must bedesigned to meet local cooking needs cookingthe local food, in the timeframes needed, withlocally available fuels. Solutions for one part ofthe world may not be applicable in other partsof the world. Past improved stoves have notalways been designed with the needs and socialpractices of end users in mind. By extensivelytesting prototype stoves with users, commercialbusinesses have been able to lessen theserisks. Experience indicates that a full portfolio

of solutions will be needed to meet the manycooking needs of the developing world including preferences for a variety of cookingoptions (just as most kitchens in the developedworld use not use a gas or electric stove, butan oven, a microwave oven, an outdoor grill,

a toaster, and many more specialized cookingdevices).

y Global Leadership: Coordination and cross-disciplinary leadership is needed to pursueintegrated solutions that address each ofthe climate, health, gender, forestry, energy,agricultural, and other dimensions of thecookstove issue. In the past decade, severalnew efforts have emerged that have broughtnew focus to the health and climate risks ofcookstoves, and new rigor to solutions to theserisks. These include the U.S. EPA-led PCIA, theShell Foundations Breathing Space program,GIZs HERA program, and SNVs global biogasefforts, as well as more isolated investments bythe World Bank, USAID, and several agenciesfocused on refugee camps (e.g., United NationsHigh Commissioner for Refugees and World FoodProgramme).

In September 2010, the United Nations Foundationand nineteen founding partners launched the GlobalAlliance for Clean Cookstoves. The Alliance is a newpublic-private initiative whose mission is to savelives, improve livelihoods, empower women, andcombat climate change by creating a thriving global

market for clean and efcient household cookingsolutions. The Alliance will work closely withprivate, non-governmental, UN and other partnersto expand efforts to address the global and localbarriers that have limited the scope of cookstovereplacements. The Alliance has set an interim goal ofhaving 100 million new homes adopt clean and safecooking solutions by 2020. Achieving this goal willlikely entail the sale through commercial distributionchannels of well over 100 million stoves in total,with both the quantity of sales and the quality ofperformance growing substantially over time (seeFigure 10-12).

The development of standards for what constitutesa low-emitting stove is essential for ensuringimprovements in performance over time. PCIAand the Alliance have joined together with thecookstove community to pursue the developmentof voluntary global standards through an inclusive,transparent process with the International StandardsOrganization (ISO). The development of thesestandards will proceed in parallel with growth in theglobal stove market. In the early years, distributionchains and businesses will be built around the sale




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of available, mostly mid-range stoves. As thesedistribution channels are built, however, neweradvanced solutions will supplant them as the earlypurchases wear out and are replaced. By the end ofthe decade, it is the Alliances goal that most stovessold will be of the advanced (efcient and very lowemission) variety. It is these more advanced solutionsthat are likely to achieve the more signicant BC

reductions, as well as the more dramatic healthbenets.

While open res or crude stoves are not a signicantsource of BC emissions in the United States, the U.S.government has been at the forefront of the effortto establish the Alliance and is a leading partner tothe Alliance. The U.S. Department of State is leadingAlliance diplomacy to raise the visibility of the issueand engage new country and other partners, andseveral agencies (EPA, U.S. Department of Healthand Human Services [HHS, including the National

Institutes of Health and the Centers for DiseaseControl and Prevention], DOE, USAID, OverseasPrivate Investment Corporation, Peace Corps,U.S. Department of Agriculture, and the NationalOceanic and Atmospheric Administration) arecontributing substantially to the Alliance throughapplied research (on technology, health, stovetesting, distribution, adoption, climate, biofuels,

forestry), nancing, and distribution.

Since its launch , the Alliance has identied up to$120 million in partner commitments, includingabout $20 million for operations, over $50 millionfor research, and up to $50 million in nancing;brought on more than 275 partners, including28 country partners; catalyzed the process todevelop international consensus standards for cleancookstoves; funded a Kenya study to assess variouscookstoves to determine the benets for childrenshealth; supported regional Alliances in Asia, Latin

Figure 10-12. Potential Growth in the Number of Households Adopting Clean Cookstoves Globallythrough 2020.The Global Alliance anticipates that the market for clean cookstoves will continue to evolve,in parallel with development of cookstove standards. The Alliance has set a goal of 100 million clean

stoves by 2020. Numbers of different stove types in the chart are illustrative only. (Reproduced from U.N.Foundation, 2011.)

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America, and Africa to spur local businesses andsolutions; built up technical capacity of regionalstove testing centers in China, Ethiopia, and othercountries; executed comprehensive market analysesof the clean cookstove sector in ve countries;supported the development of indoor air guidelines

by the World Health Organization; ensured inclusionof household air pollution as a risk factor for non-communicable diseases in the Political Declarationfor the UN General Assembly; sponsored theFifth Biennial PCIA Forum and two internationaltechnical research workshops; begun integration ofthe Alliance with the Partnership for Clean IndoorAir; and worked with UN agencies to improvecollaboration among UN cookstoves and fuelprograms. The Alliance recently released a rst-eversector-wide strategy report (called Igniting Change;U.N. Foundation, 2011) that lays out a strategy foruniversal adoption of clean cookstoves and fuels,and its 10-year business plan is forthcoming in 2012.

Solutions on this scale are needed to resolve thetremendous human health and environmentalburdenincluding the climate impactsoftraditional cookstove use. As the above discussions

indicate, large scale success in this eld may bewithin reach. Substantial reductions in BC on theorder of 90% to 95% per household likely dependon switching to cleaner fuels or advanced biomassstoves. Such highly efcient, clean stoves help meetmultiple goals, including fuel efciency, health

protection, low climate impacts, and reduction ofoutdoor pollution (Venkataraman et al., 2010).

Currently, simple unimproved stoves dominate themarketplace. Most current improved stove salesare of the intermediate variety rocket stoves orother solutions that achieve important health11and fuel use benets, but will not achieve the largehealth and BC benets sought. As the Allianceadvances towards its interim goal of reaching 100million homes, solutions will need to evolve towardscleaner fuels and more advanced stoves to ensurethat substantial public health and BC benets areachieved. Additional research and innovationsare needed to bring these very clean solutions tomassive populations and to move as rapidly aspossible to achieve the health and climate benetsthat advanced stoves can bring to families and theenvironment.

11 As head of the Department of Environmental Health Engineeringat Sri Ramachandra University in Chennai, India, KalpanaBalakrishnan has said, [These] existing improved stoves have to gosome way before they can meet a health-based standard, but theyare much, much better than the traditional stoves we have now(Adler 2010)


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