16 Aug 2011

Wynand Oosthuysen

KDC Energy Conservation

AMRE-SACEA JOINT MEETING

• Impact of Electricity on KDC

•Escalation on Electricity Cost

•Make-up of the Bill

•Counter measures taken

Content

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Impact of Electricity on KDC

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kWh

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KDC Energy Consumption

Reduction of and average of 44 MW

Impact of Electricity on KDC

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Electricity cost increase year on year even though theenergy consumption is decreasing.

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KDC Energy Cost

Escalation on Electricity Cost

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Low Season Tariff

Peak Standard Off Peak

Expect increase of 28.5%

Escalation on Electricity Cost

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hHigh Season Tariff

Peak Standard Off Peak

Expect increase of 28.5%

Make-up of the Bill

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25.7%

15.0%

27.6%

9.3%

5.4%0.0%

8.0%

8.6% 0.3% Consumption: Off Peak

Peak

Standard

Electrification and Rural SubsidyRetail Enviromental Levy ChargeReactive Energy Charge

NAC and TX NAC

Network Demand Charge

Admin / Serv / Fix

Make-up of the Bill

8

83.0%

8.0% 8.6%

0.3%

Total Energy Dependant Charges

NAC and TX NAC

Completed Initiatives:• Pump scheduling.• Geyser Load switches in low density residential

areas.• In line heater at high density residential areas.• Energy efficient lighting.• Guide vane control on main ventilation fans.• Re-evaluate power factor correction installations.• Compressed air load control.• KDC East 1# Water System Optimization• Energy recovery turbines K3 & D5 - ±6.5 MW• Introduction / extension on closed loop cooling.• Extensive installation of ventilation seals.

Counter measures taken

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Pump Scheduling at 5 Shaft KDC WestCompleted Initiatives

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Intelligent Pump Scheduling and ControlOpportunities • East 5#

Scheduling out of Eskom evening peak time i.e. 6pm to 8pm4 Stages to surface with 6 pumps per stage/level into dams on 52L, 42L, 23L and IPC with current dam capacity

Max Demand Load Shift 8.22 MW

Pump Scheduling at 5 Shaft KDC WestCompleted Initiatives

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12.547 MW Shifted

Geyser Load switches in low density residential areas-Completed Initiatives

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Village Geyser Control

Opportunities • East Village (~976)• PhomolongVillage (~215)• LetsasingVillage (~354)•West Village (~160)• Single Quarters (~16)• Other (~9)

TOTAL ~ 1,730Households

Max Demand Load Shift between 18h00-20h00

1.06 MW

Geyser Load switches in low density residential areas-Completed Initiatives

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1.095 MW Shifted

In line heater at high density residential areas.Completed Initiatives

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In line heater at high density residential areas.Completed Initiatives

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0.943 MW Shifted

Energy efficient lighting.Completed Initiatives

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Original installed lighting capacity on KDC West

Post implementation installed lighting capacity on KDC West

Reduction in installed capacity was 5961.6kWAt a load factor of 33.33% (8 hours/day) resulted in an average savings of 1.987MW

Guide vane control on main ventilation fansCompleted Initiatives

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Guide vane control on main ventilation fansCompleted Initiatives

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MW

KDC West Main Ventilation Fan Demand

Demand clipping during evening peak of ± 5MWAverage demand saving of 1.88 MW per month

Completed Initiatives

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KDC West - Reactive Energy - Total Mine

Excess Reactive Energy (kVARh) Off Peak Standard Peak

Re-evaluate power factor correction installations

16.6 Mvarh to 12.9 MVarh to 7.7 MVarh

Compressed air load control.

• 50 Valve installation done on various shafts.

• Compressor guide vane control upgraded.

• Individual compressor load sharing and between compressor houses

Completed Initiatives

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Compressed air load control.Completed Initiatives

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KDC East 1# Water System OptimizationCompleted Initiatives

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3.219 MW Average Weekday saving

New Initiatives:.• More Energy recovery turbines at K4 21 lev. – 0.5 MW.• Reverse flow pumps at KDC West 4 shaft 2 MW• Refrigeration plant load shifting K4 & D5 – 9 MW.• Introduction of an Ice Plant at K3 - 7.65 MW• DSM Air project at K7 - 1.5 MW• Heat pumps at industrial change houses – 1.5 MW• Additional Geyser Load switches in low density residential

areas – 1.26 MW• Compressor intake filter refurbishment – 2.2 MW.• Concentrated Solar Power (CSP) for Gold Plant• Compressed air leak detection and fixing at KDC West.• KDC fans Impeller efficiency – axial flow fans.• Heat recovery from compressors.• 3CPS.

Counter measures taken

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New InitiativesHeat recovery from Compressors

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Pump 1

Existing Cooling Tower

Existing Aftercooler

Existing Aftercooler

Existing Aftercooler

Compressed Air To

Underground Users

New Heat Exchanger

New Heat Exchanger

New Heat Exchanger

Compressor with Intercoolers

Compressor with Intercoolers

Compressor with Intercoolers

Pump 2

Pump 3

Hot Water (60°C) to Storage Tank

Cold Water Return

Thermal Storage Tank (typically >400m3)(to absorb variations in

supply and demand of hot water)

Pump 4

Cold Water from RWB

ILH ILH

Showers Showers

Change House

Calorifier

Hot Water Return

Hot Water Supply A B A B

Valve opens when flow to

showers is zero, and vice

versa

Valve A normally open and Valve B closed.

When no hot water in Storage tank or when no discharge pressure on Pump 4, then Valve A closed and Valve B open.

HOSTEL AREA

COMPRESSOR HOUSEExisting In-Line Heaters (ILH) are only on standby. Their electrical energy consumption are replaced by the thermal energy from the compressor heat recovery system.

•KDC West 5 Shaft - 4.337 MW

•KDC West 1 Shaft – 5.843 MW

•KDC East 4 Shaft – 3 MW

3CPSNew Initiatives

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New Initiatives

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New Initiatives3CPS.

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FRIDGE SURFACE

PRVPRVPRVPRVPRV

50,5L

42L44L46L48L50L

23L

21L

IPC3.8 MW Turbine

3CPS

|c

c

42 L

23L

42L

LP filling pump

1.0Ml Balance dam

FRIDGE SURFACE

PRVPRVPRVPRVPRV

50,5L

42L44L46L48L50L

23L

21L

IPC

3CPS

|c

c

|c

c

42 L

23L

42L

LP filling pump

21L Booster pump

Bypass dissipator

KDC West 5# 42L--De-watering reticulation after 3CPS

Questions ?

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