ModelingRenewableMicrogrids inSouthAfricaBassConnections

inEnergy

Kerim Algul (Pratt '17), Nitish Garg (Pratt MEMP '17), Ryan Hussey (Trinity '17), Cassidee Kido (Pratt '17), Ashley Meuser (Pratt '19), Savini Prematilleke (Pratt

'19), Tyler Wakefield (Trinity '18)

We would like to thank Bass Connections in Energy for the resources they have provided and thank Dr. Emily Klein, Dr. Josiah Knight, and Chris Dougher for their invaluable guidance.

1.1 billion people around the world have little tono access to reliable electricity. Electricity accessis essential to economic growth and development,but cost and physical barriers make it such thatconnection to the central grid is years away formany rural communities. As shown in Figure 1,many areas in South Africa are still unelectrified.Microgrids can bring power to these communitiesat a smaller scale, giving them the economicbenefits of electricity access without the costs ofconnecting to the larger grid. Powering themicrogrid with energy sources already found inthese communities, including wind, solar, andbiogas from cattle waste, makes this system self-sustaining with a low environmental impact. Thisproject evaluates the potential for improvingelectricity access in the KwaZulu-Natal andEastern Cape regions of South Africa (circled inFigure 1) through the implementation of amicrogrid. HOMER, a program developed by theNREL that models microgrids' physical behaviorsand costs, was the main tool used in evaluatingdifferent microgrid configurations. This analysisproposes three different microgrid configurationsand assesses their technical and economicfeasibilities.

Rural microgrids using combinations of wind, solar PV, andbiogas combustion for this region of South Africa aretechnologically feasible, but will require subsidization fromgovernment or NGO sources to be economically viable.However, all three models produce high quantities ofexcess electricity given their dependence on variable windand solar coupled with storage. If communities were ableto take advantage of unpredictable excess electricitythrough flexible manufacturing operations that generatedincome, the systems may become economically viablewithout subsidization. Likewise, the high likelihood of gridconnection throughout SA within 25 years presentsopportunities for communities to sell excess electricity tothe grid, increasing the economic viability of the systems.Sensitivity: All models are highly sensitive to theavailability of cattle waste. In areas that have concentratedlivestock operations, the higher availability and lower costof biomass alter the composition of energy resources tofavor biogas combustion, lowering the system cost.

CommunityA:75Households

CommunityB:400 Households

CommunityC:1250Households

• ElectricLoad:linearincreasewithcommunitysize• CattleWaste:linearincreasewithcommunitysize,2.5

Cattle/Household,15kgwaste/cattle/day,25%wastereclaimed

• Annualelectric loadincreaseof1.5%(Multi-YearModel)• Inflation=6.5%,NominalDiscountRate=8%• Controllercapital,replacement,andoperationand

managementcostsunknown;assumedzero• Conversionrate:1USD:0.07ZAR• Averagehouseholdincome:USD$1080.4• Doesnotconsidercostoftransmissioninfrastructure

• <0.01%CH4reductionperyear• Potential25%N2Oreductionperyear• Minimalnegativebatteryimpacts• Spatialimpactsofthewindandsolarresourcescould

affectagricultureinthearea

CommunitySize(households)

ElectricLoad

(kWh/day)

PeakLoad(kW)

PV(kW)

Wind(kW)

BiogasGenerator(kW)

Storage(kW)

Converter(kW)

CostofEnergy

NetPresentCost(25years)

OperatingCost InitialCost

75 98.1 13.81 83.1 0 2 79.47 14.5 $0.273 $204,628 $3,364 $134,145400 523.3 73.68 349 96 10 298.01 68.1 $0.25 $999,365 $13,815 $709,9491250 1635.0 230.2 874 207 30 1,142.38 228 $0.243 $3,030,000 $38,622 $2,230,000

Multi-YearModel• PVincreasesto 130kW• Nochangein biogas• Storageincreasesto 119.16kW• COEincreasesto $0.317

• Converterincreasesto 21kW• NPCincreasesto $285,797• OCincreasesto $4,054• ICincreasesto $200,866

Multi-YearModel• PVincreasesto420kW• Windincreasesto900kW• Nochangeinbiogas• Nochangeinstorage

• COEincreasesto $0.276• Converterincreasesto90kW• NPCincreasesto $1.10M• OCincreasesto $14,190• ICincreasesto $805,204

Multi-YearModel• PVincreasesto1600kW• Wind increasesto 375kW• Nochangeinbiogas• Storageincreases to 1,490kW

• COEincreasesto $0.304• Converterincreasesto350kW• NPCincreasesto $4.56M• OCincreasesto $53,726• ICincreasesto $3.44M

Introduction

Conclusion

ModelAssumptions

EnvironmentalImpacts

Figure1:ElectricityAccess MapofSouthAfrica

PaymentMethodology COE($/kWh) AnnualRevenue PresentValue(25Years)

NPC($3,030,000)minusPV

HH'spayavg.COEinSA $.100 $59,678 $1,250,240 $1,779,760HH'spayavg.of8%ofincome $.181 $108,040 $2,263,431 $776,569HHpayenoughtomeetNPC $.243 $145,016 $3,030,000 -

PaymentMethodology COE($/kWh) AnnualRevenue PresentValue(25Years)

NPC($999,365)minusPV

HH'spayavg.COEinSA $.100 $19,100 $400,153 $599,212HH'spayavg.of8%ofincome $.181 $34,573 $724,298 $275,067HHpayenoughtomeetNPC $.250 $47,751 $999,365 -

PaymentMethodology COE($/kWh) AnnualRevenue PresentValue(25Years)

NPC($204,628)minusPV

HH'spayavg.COEinSA $.100 $3,581 $75,014 $166,405HH'spayavg.of8%ofincome $.181 $6,482 $135,806 $135,430HHpayenoughtomeetNPC $.273 $9,775 $204,628 -

Unelectrified

Unelectrified withoutsignificantpopulation

Electrified