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Priority GeothermalDirect-Use Applications for Kenya: A Pre-feasibility Study for Crop Drying

This is the final version of this report. All views expressed in this Report are those of the authors alone and do not necessarily reflect the official views

of the United States Agency for International Development.

Prepared for USAID – Washington and

The Kenya Geothermal Development Company (GDC)

byLand O’Lakes International

Development andWinrock International

through a VEGA LWA Cooperative Agreement

The VEGA/Powering African Agriculture (VEGA/PAA) Project

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SummaryGeo-agricultural drying is the use of geothermal energy for the drying of various grains, tea, nuts, herbs, vegetables and fruits. Drying or dehydration are moderate-temperature uses of geothermal energy (often < 100°C) and have numerous potential applications in Kenya. Current crop drying practices in Kenya consist of sun-drying, wood/oil fired boiler systems and electric heaters and therefore are prone to unreliability, high cost and environmental degradation, which can be reduced or eliminated with the use of geothermal energy. Drying operations, in some cases, can be cost effectively relocated to areas where the geothermal resource exists, especially where crops are already transported long distances. Kenya’s reliance on imported grains will be reduced as a result of the lower cost and high reliability of geothermal drying giving better moisture content control and minimizing crop rejects. Tea is a commodity that has huge potential savings as a result of Direct-Use of geothermal and requires an in depth pre-feasibility study to ascertain the economics of longer distance transport versus the gains from lower cost geothermal energy. Other crops, such as maize, may also be the subjects of a pre-feasibility study that would analyze and make the business case for applying geothermal energy to drying maize in Kenya.

CropDrying

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Priority Geothermal Direct-Use Applications for Kenya:A Pre-feasibility Study for Crop Drying

Crop Drying - Market Sector OverviewThe principal market sectors that require drying in Kenya are:

• Grains–Maize,Wheat,Barley,Rice,SorghumandMillet• Berries–Coffee• Fruits–Mango,Banana,Coconut,Pineapple,Papaya• Nuts–Macadamia,Groundnut,Cashew• Leaf–Tea• Vegetables–Mushroom,Carrots,Beans• Flowers–Pyrethrum

1. Sector Background/History

At the smallholder level, most drying in Kenya is done using the sun. Only at industrial levels are other drying systems used. The tea and coffee industries are both very reliant on wood fired boilers for drying and the grain and pyrethrum sectors use HFO (Heavy Fuel Oil) boilers but only at the largeroperations.

2. Standard Drying Industry Practices

Various vegetables and fruits products are dried using continuous belt conveyors or batch (truck) dryers with air temperatures ranging from 40°C to 100oC(Figures1and2)andgraindryingisoftendonewithcounter-flowhotairdriers(Figure3).Geothermalenergyisusedinoveradozencountriesfordrying various grains, vegetable and fruit crops as in the examples of a tomato dryershowninFigure4andpyrethrumdryershowninFigure5.

Figure 1 Continuous belt dryer used for

onion dehydration in Nevada, USA. Approximately 4,500 to 6,800 kg/hr. of raw product are dried from 80% to 5%

moisture producing 680 to 815 kg/hr. of dried product using 42 GJ/hr. (35 MJ/kg). Temperatures range from 96 to 74oC with onion depths from 5 cm to 2 m. A 3.6-m

wide belt dryer with onions is shown.


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Figure 2A small batch fruit dryer in Mexico. Approximately one ton of fruit can by dried from a moisture content of 80% to 20% in 24 hours. The building is 4.0 m x 1.35 m x 3.2 m high with 30 trays for each truck 1 m x 1 m x 5 cm high. The required drying temperature is from 60oC to 74oC with an air flow of 240 to 300 m3/min.

Figure 3Counter-flow rice dryer in Macedonia using 75oC resource and 35oC air. The plant uses 1,360 kWt (4.9 GJ/hr.) to dry 10 tonnes/hr from a moisture content of 20% to 14.

Figure 4Small tunnel tomato drying facility in northern Greece. It uses 59oC geothermal resources to dry 14% kg/hr. of moist tomatoes and produces 4.0 MTs/yr of dried product.

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Figure 5 The Eburru geothermal grain and flower

drier has been in continuous operation for over 75 years.

The Eburru geothermal drier, built by an English settler around 1939, is used to dry Pyrethrum flowers and maize (white corn). The drier is supplied with geothermalwaterfromawellat95°Cadjacenttothebuilding;however,dueto leakage and lack of insulation around the pipes, the heat supplied in the building is only 43°C. Some of the geothermal water and condensation is gathered locally for consumption as drinking water as well. The drier is used by 110 members of a local cooperative, who pay about 10 shillings/lb. (about 12UScents)todrytheirproducts.

In El Salvador, pineapples, apples, bananas and coconuts are dried with geothermal energy at the Berlin field and used for local consumption.Guatemala has a geothermal-powered fruit drying facility that produces dried pineapples and apples for export. Other countries with geothermal-powered crop driers include: include Serbia (wheat and other grains), New Zealand(Lucerne or alfalfa), Philippines (coconut meat), Mexico (fruit) and Iceland(seaweed).

3. Market Size/Demand

The main food crops grown in Kenya, in order of importance, are: maize, beans, Irish potatoes, wheat, rice, cassava, sorghums and millet. Small-scale farmers inKenyaproduceabout75%ofthecountry’sstaplefoodsandvegetablesbut

110 members of a local cooperative, use the Eburru drier and pay about 10 shillings/lb.


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face a myriad of problems ranging from unreliable weather, lack of on-farm storage capacity, unpredictable farm input prices and volatile markets for their farm produce. The country’s national and household food security strongly hingesonmaizeproduction,processingandmarketing.FoodcropsgrowninKenya are almost exclusively used for local consumption and importation of maizeandwheatisnecessarytomakeuptheshortfallatapproximately10%and90%oftheannualproductionrespectively.

4. Crop Production/Supply

Asummaryofcropproduction inKenyafrom2000to2013 ispresented inTable 1.

Maize Kenya relies heavily on maize as the staple food, either green, milled or in dry grain form. The Great Rift Valley region, on average accounts for over 80 percent ofnationalmaizeproduction.NyanzaandWesternregionscontributesabout14percenteachtonationalmaizeproduction.Maizeproductionincreasedbynearly50%from2000to2010buthasshownlittlegrowthsince.

Wheat Wheat production increased by nearly 200% from 105,000MT in 2000 to312,000MTin2012.

Beans Beans form an essential part of the protein in Kenyan diets. Production ofbeans in the last five years has not been stable. Overall production of beans declinedby16percentintheyear2010from459,00MTin2009to387,000MTin2010.Theareaunderproductiondeclinedsignificantlyby28percentfrom960,705hectaresin2009to689,377hectaresin2010.Therewasnosignificantimprovement in yield. The drop in production was attributed to inadequate rainfall.

Sorghum Theproductionofsorghumincreasedby30%2000to2012withsomeslightimprovementontheyieldperhectareof2bagsfrom6to8bags.Theincreasein production is attributed to promotion of sorghum as a drought resistance cropinthearidandsemi-aridlandsregions(ASAL)ofthecountryandfurtherdue to attractive prices from the increased consumption. Kenya Agricultural Institute in collaboration with a Kenyan leading brewer is promoting sorghum variety to supplement barley and therefore farmers have prospects of good returns from sorghum enterprise in the near future.

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2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Wheat 105 230 300 196 197 225 300 225 219 512 256 268 300 312

Barley 75 75 75 75 75 75 75 75 75 75 75 75 75 75

Rice 33 36 24 33 40 40 46 31 15 36 53 46 55 60

Millet 70 70 72 70 50 65 70 70 40 50 70 70 70 70

Sorghum 135 140 90 130 70 130 140 140 60 95 164 200 175 175

Macadamia 4.9 5.8 6.4 6.5 10.5 11 11 12.5 13.5

Coffee 101 52 52 56 51 45 52 52 42 54 42 41 51 54

Tea 293 324 328 310 369 346 314 398 371 369

Maize 2160 2792 2430 2710 2140 2670 3000 2930 2367 2439 3222 3100 3200 3200

10000

1000

100

10

1

1000

s M

T

Table 1. Annual Major Crop Production in Kenya Since 2000


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MilletMillet,likesorghumisdroughttolerantandthriveswellinmarginalareasofEastern and Nyanza provinces. Eastern province has the highest potential.Productionhasremainedconsistentoverthelast15yearsexceptforrainfallrelated variances.

Rice Riceproductionhasincreasedby80%from2000to2012.

Barley Malting barley is grown almost exclusively under contract for the breweryindustry and the production volumes are strictly controlled according to the industry’s needs.

Coffee Coffee production halved between 2000 and 2001 and remained staticsubsequently except for variances associated with weather fluctuations.

Tea TeaisoneoftheleadingforeignexchangeearnersinKenyaaccountingfor26%offoreignexchange.Theareaunderteaproductionincreasedfrom158,394hectaresin2009to171,916hectaresin2010.Teaproductionrecordeda26%increasefrom2003to2012.

Pyrethrum Pyrethrum has been grown in Kenya since 1936 with a peak in production in 1993ofapprox.18,000MT/yeardriedflower,giving220MTofextract.Currentproduction is at an all-time low of 400MT/year dried flower.The installedcapacityofthePyrethrumBoardofKenyaprocessingplantis30,000MT/year.

Key Players in Crop Production, Storage and Drying—Grain SectorThe National Cereals and Produce Board (NCPB) is the government bodyresponsible for overseeing the procurement, management and marketing of allgrain inKenyaand theyhandleapproximately1.71millionMTannually.SmallholdersinKenyagrow75%ofthegraincrops,whicharesoldtomillers.Approximately 150 millers operate in Kenya, the largest being MombasaMillers,PembeMillers,PremierMillersandUnga.Theremaining25%ofgraincrops are grown on medium to large-scale farms.

One example of a grain handling/drying operation in Kenya (visited by the VEGA/PAA team) is Lesiolo Grain Handlers (LGHL). They process approx.100,000MT/year,ofwhich70%isdriedattemperaturesrangingfrom70°Cto100°Cdependingonthecroptoreducemoisturecontentto13.5%.Grainis

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transportedfromasfarawayas250km.LGHLhastwositesstrategicallylocatedoutsideofNakuru in thecenterofoneof thekeygrain-producing regions.TheLanetsite(Figure6a)boasts30,000metrictonscombinedcapacityinaconfiguration of 16 silos and 8 wet bins. It has the most modern equipment inEastAfrica:twoCimbria54tondryers,twoCimbriaDelta120cleaners,abeltconveyor system and a mini-dryer to cater to smaller customers. It is capable of handling bulked or bagged grain and has a bagging unit to accommodate purchasers with specific needs. It also has a full-service laboratory, which is able to grade moisture, protein, bushel weight and other quality parameters. The second site leased from NCPB, has 50,000 tons capacity has 14 silosand5starbinsanda100tondrier.Allstorageisoutfittedwithmodernpestcontrol and temperature monitoring equipment that monitors conditions continuously using an automated system.

LGHLusesan industrialdieselboiler forthedryer.Thedryingcapacity is36MTperhourbasedondesignconditionsofmoisturecontentreductionfrom17to13percent,withambienttemperatureat20°C,relativehumidityat60%anddrying air temperatureof 85°C.Their electrical energy costs are about15millionK.Shsperyear(US$187,500)withabout5percentduetolighting.Thecostforfueloilis30millionK.Shsperyear(US$375,000).Theyhavea500kVbackupgenerator.LGHLalsohaveportablegraindriers(Figure6)forrentwith a capacity of 12MT/hr. using 90°C air.This equipment could easily beretrofitted to use geothermal energy and trucked to a central geothermal site, be hooked up to geothermal fluid for heat and provide grain drying for local farmers at more competitive costs.

Figure 6a Lesiolo Grain Handlers – Nakuru

15million K.Shs is Lesiolo Grain Handlers annual electrical cost.


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Figure 6bSilo storage and portable grain dryers.

Key Players in Crop Production, Storage and Drying—Tea Sector In the tea sector there are the large multinational companies like Unilever and Finlays.ThesmallholdersundertheKTDA(KenyaTeaDevelopmentAgency)umbrella also produce a significant proportion of the Kenya tea production. Due to the potential of Direct-Use geothermal energy in the tea industry the VEGA/PAAteamvisitedbothamultinationalplantation(FinlayTeainKericho)and a KTDA factory supplied by smallholder growers as summarized below.

TeawasintroducedintoKenyabytheBritishin1903andhassincebecomean important export crop that depends on sound drying techniques. Tea is the largest export crop and a major foreign exchange earner for Kenya. Unlike other major tea producing regions of the world, Kenya relies mainly on the exportmarketwithupto95%ofitsteabeingsoldinbulkformtothreeexportdestinations. Annually, tea contributes approximately about 1/4 of Kenya’s totalexportearningsand1/20oftheGDP.Sustainabilityoftheteasectoriscritical to Kenya’s economic well-being and development. Any improvements that can be made by applying geothermal energy can help make the Kenyan tea industry more competitive globally.

The KTDA (KenyaTeaDevelopment Agency Ltd.) is the leadmanagementagencyinKenyaforabout560,000small-scaleKenyanteafarmersandoperates

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65teafactorieswithacapacityofover15,000MTofgreenleaftea.Originally,KTDA was founded as the Kenya Tea Development Authority in 1964, soon after independence, as a parastatal enterprise to promote small tea farms, which were previously considered not viable. The KTDA was incorporated in 2000asaprivatecompany.KTDAisnowalsoreplicatingitsbusinessmodelinRwanda, where the company is managing two tea factories.

The smallholder tea farmers are KTDA shareholders and typically operate on farmsof lessthan1hectareeachinsize(i.e.560,000farmersoperateabout1.5millionacres).TheKTDA farmerspluckabout1billionMTofgreen leafannually.TheKTDAteafactoriesproduceabout250millionMTofblackteaannually but have no green tea production. KTDA contractually manages these factories for the small-scale tea farmers. The KTDA factories typically purchase firewood on the open market. The small tea farmers organized under KTDA need heating alternatives the most since they do not have access to tree lot plantations, unlike corporate farms.

The KTDA managers estimated that the average radius for tea leaf collection is approximately 4 to 10 km from the factory. When queried whether itwas possible to transport tea leaves longer distances after picking, it was concluded there were no technical impediments and that as long as the tea could arrivewithin about 15hours, itwas technically possiblewithoutaffecting tea quality. The KTDA managers even cited a case where tea has been transported by small scale growers from distances over 100 km in the past to KTDA factories when they were less in number and further apart, with no decline in tea quality (Ragati region).

CoffeeisgrownbymultinationalslikeSocfinafandtherest,amountingto50%of the Kenya production, is from smallholders.

Figure7showsthegeneralareaformainfoodcropsgrowninKenya.Principalareas for tea and coffee crops are as follows.

Tea: • WestofRiftValley–Kericho,Nandi,KakamegaandCherenganiHills.• East of Rift Valley – Nyambene, Nyeri, Muranga, Kiambu, Thika andMaragua.

Coffee:

• AroundMt.Kenya–Nyeri,Muranga,Kirinyaga,EmbuandMeru.• Othersareasinclude–Kiambu,MachakosandSolai.


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Provinces

Millet

Maize

Sorghum

Wheat

Barley

Cassava

Rice

Key

Figure 7 Key Geographic Locations of Main Crops

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5. Crop Market Growth and Trends

Kenya’spopulationhasgrownfrom10.7millionin1960to47.8millionin2012withapproximately35%growtheverydecade.Itislikelythereforethatfoodcrop growth will continue in line with the expected population growth and the use of geothermal heating, to help crop quality and production, will be a vital factor in feeding the population. Kenya tea and coffee have extremely good reputations for quality and the demand is likely to continue to grow both for local consumption and for export. Use of geothermal to reduce the cost of tea production will make Kenya tea more competitive for the export market.

6. Regulatory Environment for Crops

AllcropscomeundertheMinistryofAgricultureandLivestockthroughthefollowing respective boards or associations:

• National Cereals and Produce Board (NCPB). The NCPB’smission isto promote free and fair trade in commodities through research and market development and ensure that there is timely accessibility of commodities to all.

• Coffee Board of Kenya (CBK).TheCBK’smissionistoformulatepoliciesand rules to regulate and develop the coffee industry in the consultation withtheMinistryofAgriculture.

• Tea Board of Kenya (TCB). The Tea Board of Kenya is mandated tolicenseteamanufacturingfactories;carryoutofresearchonteathroughits technical arm, theTea Research Foundationof Kenya; the registergrowers, buyers, brokers, packers, management agents and any other persondealingintea;andpromoteKenyateainboththelocalandtheinternationalmarkets.TheBoardalsodisseminatesinformationrelatingto tea and advises the Government of all policy matters regarding the tea industry.

• Pyrethrum Board of Kenya (PBK). The PBK is a Government ofKenya enterprise with the exclusive right for the processing of Pyrethrum.

Key AgenciesKenya Agricultural Research Institute (KARI) is a premier national institution bringing together research programs in food crops, horticultural and industrial crops, livestock and range management, land and water management, and socio-economics. KARI promotes sound agricultural research, technology generation and dissemination to ensure food security through improved productivity and environmental conservation.


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Kenya Plant Health Inspectorate Service (KEPHIS) is the agency in Kenya with mandate to protect Kenya’s agriculture from pests and diseases that could impact upon the environment, economy and human health.

7. Crop Drying Issues and Challenges

KTDA is facing serious future firewood shortages and unsustainable wood supply. They have been doing some limited reforestation projects with about 150,000seedlingsplantedannuallyatanestimated75%survivalrate.KTDA’sgoal is for each factory to establish 600 acres of forest for future firewood production.Trees(mostlyeucalyptus)areharvestedafterabout8years.LandavailabilityisanissuewiththeKenyanForestryService.KTDAhasconductedpilot testing with their boilers to use bamboo as a firewood alternative. KTDA isproposingtolog5,000hectaresofbamboofromKenya’sAberdareForest,but is meeting stiff resistance from environmentalists.

8. Re-location Potential

Potential co-location already exists for some tea production and geothermal resourcesinKenya.Manyoftheteagrowingandprocessingareasarelocatedin the Great Rift Valley. Power tea processing activities are within geothermal regions for some Kenyan tea factories. Sites have to be verified on a case-by-case basis. Alternatively, some tea factories may choose to move activities to known geothermal sites, such as Menengai. Given the high-energyrequirements for tea drying and processing, the tea industry could reduce its energycostsby20%ormorefromtheincorporationofgeothermalheating.

Crop Drying Energy ConsiderationsDrying is a critical operation for many essential food crops in Kenya. Drying is also needed for tea, coffee, pyrethrum and macadamia nuts, which are all important exports from Kenya. To increase the storage life of maize and maintain a high quality product, it is recommended to dry maize to below a moisturecontentof13.5%.Thisistoreducegrowthoffungi,insectinfestationin storage, reduction of respiration of kernels and prevention of germination while the kernels/seed retains its germination potential. The characteristics of maizeare:bulkdensity721kg/m3 and moisture content range for handling from7.5to23.1percent.Theequilibriummoisturecontentofmaizeat25°Cat20%relativehumidityis7.1%,andat60%relativehumidityis12.4%.Maizehas

150,000 seedlings are planted annually at an estimated 75% survival rate.

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the largest kernels of any grain and thus will dry at a slower rate. To decrease the chances of contamination, the drying of produce on bare ground and on roadways should be discouraged.

1. Current Drying Energy Practices

Smallholder food crop, coffee and pyrethrum operations depend almost entirely on sun drying with the inherent risks associated with weather affecting the quality and reliability of supply.

Figure 8 Traditional air/solar drying of maize in

Nakuru.

Figure 9 Finlay’s Chomoganday tea factory Thermax

boiler fueled by firewood.


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Equipment Several different dryers can be used to dry cereals: cross-flow, concurrent-flow,counter-flowandmixedflowdryerssimilartothoseshowninFigures1to 4. The tea industry uses withering troughs and fluid bed driers.

2. Drying Energy Consumption

Thermal LoadsSome of the factors that can affect energy use are dryer design, outdoor weather, initial and final moisture content, corn hybrid, corn depth and thickness in dryer, drying air temperature and airflow.

Maize Drying A commercial cross-flow maize dryer has a recommend drying temperature of 82.2°C, the burner capacity is 57.2 X 106 kJ/h and a retention time atrated capacity is one hour. The specifications for a commercial three-stage concurrent-flow maize dryer with counter-flow cooler (see Figure 3) areinletmoisturecontent24%wetbulb,dryingairtemperature200°Candfuelconsumption 3933 kJ/kg. In the example of a grain dryer inNakuru usingdiesel-firedboilers,thefuelconsumptionis30liters/MTtoreducethemoisturecontentfrom18%to12%atacostofapprox.US$38/MT.

Wheat Drying The specifications for a mixed flow wheat-and barley dryer are: capacity at 4%moisture removal 14.5 ton/h, drying air temperature 68°C and heatconsumptionof760X103kcal/h.

Tea Drying KTDA tea leaves are delivered to the factory and firstwithered at 85°C forabout10hourstoreacha65%moisturecontent.Fermentationisthencarriedout at about 72°C for 90minutes, further dropping themoisture contenttoabout55%.Thisisfollowedbythefinalstagewherethefluidbeddryersoperateatabout145°Cdryingteafor20minutes,wheretheteaexitsatabout3% moisture content. Drying is the process that stops fermentation andintroduces a stable product of low moisture content that can be shipped and stored. It involves the physical removal of moisture and it’s a crucial process as it seals in all the flavor, aroma and character of the tea that are released through brewing. Proper drying can make the difference between a mediocre tea and a superb tea.

Firewoodisusedforboilerstomeetthermalenergyrequirements,withHFOused as standby in some factories. The KTDA managers estimate that between 1,000-2500m3offirewoodareusedpermonthperfactoryatacostof17-20

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US$/m3,whichrelatestoapproximatelyUS$102offirewoodpertonofteaproduced.

TheFinlay’sChomogandayteaprocessingplantatKericho(Kenya)usestwoJ.F.McCoyfluidbeddrierstomakeblacktea.Thecrushedteaentersthedrierat68%moisturecontentand leaves thedryerat3%moisturecontent.Thecrushed tea enters the drier at about 90°C from the fermentation process and spendsabout15to20minutesinsidethefluidbeddryeratatemperatureof150°C.Afterdryingtheteasleavesarethensortedbysizeandfibercontent.

The Chomoganday tea factory has more than 6 wood-fired boilers for processing operations, with the number operational depending on the amount of tea processed. Most boilers are twin drum 3 pass smoke tubeThermaxLtd.(India)boilers(Figure9),ratedat2.8MW,producing4.5MTofsteam and operating at between 10 and 30 bar. The boilers operate on a closed systemusingriverwaterheatedanywherefrom178to220°C(tooperatethefluidized bed dryers), with an 80°C return temperature. The boilers are turned on one hour before the workers arrive for the morning shift and shut off one hour after they leave for the day. The wood residue is cleaned out from the boilers one day a week.

TheChomogandayteafactoryusesabout500m3 per week of firewood, or about2.7m3 of firewood per ton of tea produced. In Kericho, firewood (with VATgoesforaboutUS$28/m3. Thus, the value of firewood used per ton of tea isapproximatelyUS$87 (aboutUS$814,320peryear).Theplantmaintainsa4-month supply of firewood on-site (~10,000 m3) to guard against fuel wood

Figure 10Crushed tea fermenting/oxidizing on its

slow trip to the fluid bed dryer in the background.


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shortages. Optimally one kg of firewood produces about 4.1 kg of steam, butproductioncanbeaslowas3.5kgofsteam,dependingontheburner’sefficiencies.

Electrical LoadsMost mechanical drying systems are also reliant on electricity for fans,conveyors, elevators, burners, etc. and the electrical load is case specific for each application. Reliability IssuesThe reliability of electric utility power is a major concern to the crop drying industry in Kenya, where frequent power outages require the use of diesel poweredbackupgenerators.ThisisanaddedO&Mcostestimatedat10%ofthe total electric cost.

3. Geothermal Energy Direct-Use Potential for Crop Drying

Tea Drying Direct-Use Potential Sinceenergycostsrepresent25to40%ofthecostofKenyanteaproduction,alternatives such as geothermal energy for improving the efficiency and reliability of energy for Kenyan tea factories are attractive and can have a dramatic competitive impact. Kenyan tea farmers can use geothermal energy for tea drying and processing. Presently, other than electricity and generators, wood is being used to process the tea, which is also bad for the environment and creates large CO

2 emissions. Potential may also exist for using binary

type geothermal power systems for tea factories to reduce electricity costs byapprox.25-50%andbemorereliable.SometeafactoriesintheGreatRiftValley may have access to as yet unknown geothermal resources.

Grain Drying Direct-Use Potential One of the world’s continuously operated geothermal driers has been

Figure 11Part of Finlay’s Sousa tea factory’s acres of firewood storage used to power the boilers.

wood is being used to process the tea, which is also bad for the environment and creates large CO2 emissions

CO2 emissions

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operated forover75years inEburru.Similardryers,ofamoremodernandenergy efficient design, could be built for use by villages in rural area to provide employment and a source of income for their products. These would be especially important for the drying of maize, to overcome the problems associated with open air/solar drying that is current practice in many area.

Geothermal Processing—DU Equipment RequirementsA geothermal heating system for driers typically consists of a geothermal supply (well, separator, steam pipe, hot water pipe), geothermal fluid disposal (injection well, surface pond), heat exchanger, storage tank, circulation pumps, valves, heat tubing or pipes and control systems. All equipment will require importation form Europe and/or USA

Geothermal Processing—Resource Co-location PotentialAs the temperatures required for crop drying are relatively low, there is potentialforresourceco-location;theoptionsinclude,butarenotlimitedto,the following:

• Locationclosetoawellheadgeneratorutilizingtheseparatedbrineforheating.

• Locationnearalargepowerplantandutilizingthewasteheatfromthepower plant, the brine and the condensate.

• More thanoneDirect-Use application canalsobe supplied from thesame source by cascading the thermal fluids according to the application temperaturerequirementsoftheindividualapplications.Forexample,aquaculture (fish farms or ponds) and/or vegetable greenhouses may be located together with the crop drier to maximize the energy use.

Geothermal Processing—Temperatures, Flows and Chemistry The geothermal resource needs to be evaluated in regard to temperature, flow rates, water quality and water chemistry, well data, and disposal methods of spent fluids. Crop drying in the Great Rift Valley can be easily accomplished with temperatures of 70°C to 90°C.

Geothermal Environmental Impacts The main environmental impacts from geothermal development are site preparation for drilling and completion and disposal of geothermal fluids afterheatextraction.Byreinjectionofspentfluids,theenvironmentalimpactof geothermal fluid withdrawals can be minimized. The impacts from factory constructionandoperationaresitedevelopment(levelingandroadbuilding);site run-off; water use and its impact on local water resources. A detailedimpact statement should be developed for any specific site. But by usinggeothermal energy instead of diesel-burning back-up generators, there will be less air and noise pollution around the sites.

70°C - 90°C Crop drying in the Great Rift Valley can be easily accomplished with these temperatures.


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Water Recovery PotentialDepending on the geothermal source characteristics and the reservoir balance there could be the potential of utilizing the condensate or brine for other applications like aquaculture and or greenhouse vegetable production.

Geothermal Crop Drying Conclusions and Recommendations Geothermal appears to offer particularly great promise for the future of the Kenyan tea industry. There are no technical impediments to transporting tea greater distances (e.g., 100 km vs. 10 km at present) to tea factories. KTDA energy managers are interested in geothermal energy for tea processing and drying potential and the sustainability of the smallholder tea grower.

1. DU Crop Drying SWOT Analysis

A Strengths-Weaknesses-Opportunities-Threats (SWOT) analysis shows thatthe potential geo-crop drying development in Kenya has a high probability ofsuccess.TheSWOTanalysisshowsthatthereisacompetitiveadvantagetodryingcropswithgeothermalenergy.(SeeTable2)

2. The Business Case for Geothermal Crop Drying

Further research intoeachvaluechainor agricultural cropwillbe requiredbefore we can analyze each specific business case for using geothermal energy for crop drying, but our initial analysis demonstrates that there is an excellent potential to apply geothermal heat directly for a wide variety of crop drying processing operations.

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• Kenyahasalargegeothermalresource• Largeexportmarketfortea,coffeeandpyrethrum• Kenyanqualityteaandcoffeewellknownabroad• Goodinfrastructuretomainmarkets• Insufficientfoodcropproductiontomeetlocal

demand of expanding population• Competitiverenewableenergysource• Environmentalbenefitsofreducingthereliance

on wood fuel

• Unreliableelectricalpower• GeothermalcropdryingrequirestrainingforO&M• Highcapitalcost• Largelyuntrainedlaborpool• Unknowngeothermalresourcesandaccessto

geothermal areas

• CarbonCreditsthroughCDM• Possibleincreaseinexportopportunities• UseofgeothermalresourceattractivetoFairTrade

market• Lowresourcetemperatureoptions• ProtectionofKenyaforest• SurvivalofthesmallholderteagrowerandKTDA

factories.

• Geothermalresourcelocationrelativetomarketand infrastructure

• Unreliablegridpower-Stand-bypowerrequired• ReplacementequipmentnotavailableinKenya• Geothermalcropdryingrequireshightech

approaches–needstrained,investedpersonnel

Strengths

weakness

Opportunities

Threats

Table 2. Geo-Crop Drying SWOT Analysis


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ReferencesMinistryofAgriculture,“EconomicReviewofAgriculture2011”,preparedby:TheCentralPlanningandProjectMonitoringUnit,RepublicofKenya.

Lund,J.W.,Freeston,D.H.,andBoyd,T.L.,2011.“DirectUtilizationofGeothermalEnergy2010,WorldwideReview,”Geothermics,Vol.40,Elsevier,Amsterdam,Netherlands,pp.159-180.

Mburu,M.andKinyanjui,S.,2012.“CascadedUseofGeothermalEnergy:EburruCaseStudy,”Geo-HeatCenterQuarterlyBulletin,Vol.30,No.4(February),KlamathFalls,Oregon,pp.21-26.

Lund,J.W.andLienau,P.J.,1998.“IndustrialApplications”,Chapter16,GeothermalDirect-Use Engineering and Design Guidebook, 3rd edition, Geo-Heat Center, KlamathFalls,Oregon.

Lund,J.W.,1998.“OnionDehydration”,Geo-HeatCenterQuarterlyBulletin,Vol.15,No.4,(July),KlamathFalls,Oregon,pp.15-18.

Lund,J.W.,1996.“DesignofSmallFruitDrierUsingGeothermalEnergy,”Geo-HeatCenterQuarterlyBulletin,Vol.17,No.1(February),KlamathFalls,Oregon,pp.24–26.

Andritsos,N.,Dalampakis,P.,andKolios,N.,2003.“UseofGeothermalEnergyforTomatoDrying”,Geo-HeatCenterQuarterlyBulletin,Vol.24,No.1(March),KlamathFalls,Oregon,pp.9-13.

Lund,J.W.,2012.TripReporttoKenya(19-31October),WinrockInternational,articleonEburruplantandtheNationalCerealandProductionBoardsiteatNakuru.

Boyd,T.,2013.TripReporttoKenya(24Mayto31May),WinrockInternational,articlesontheNationalCerealandProductionBoardmaizeplant,Nakuru,andthepyrethrumand maize drying plant at Eburru.

Boyd,T.,2013.Direct-UseTripReport(July7-19),WinrockInternational,articlesontheLesioloGrainHandlersandmeetingnoteswiththeMinistryofAgriculture.

Foster,R.,2013.TripNotes(July),WinrockInternational,notesontheFinlayTeaFactory

and Kenya Tea Development Authority.

A Pre-feasibility Study for Crop DryingOctober2013

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