Efficient Electrical Energy Management in the Mining Industries 1

8/9/2019 Efficient Electrical Energy Management in the Mining Industries 1

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Paper presented at the

First UMaT International Mining andMineral Conference

Solomon NunooDepartment of Electrical and Electronic

EngineeringUniversity of Mines and Technology, Tarkwa


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Introduction

Background of Mining Sector of Ghana

The Need for Energy Management

Energy Management Principles

Case StudyConclusions


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Introduction






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Ghana is located in Western Africa, has landcoverage of 238,500 km2 with approximately 23.4million people (2008 estimate) and about 54 % ofthe population live in rural areas (2005 estimate)(Owusu-Ansah, 2008).

The economy of Ghana mainly depends on mining,agricultural production, industrial and small businessactivities which largely depend on electrical energy.

Electrical power generation, transmission anddistribution are mainly carried out by Volta RiverAuthority (VRA), Ghana Grid Company (GRIDCo),the Electricity Company of Ghana (ECG) andNorthern Electricity Department (NED) of VRArespectively.


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Figure 1 Installed Electricity Generation Capacity of Ghana


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Figure 2 Electricity Generating Capacity of Ghana Based on the

Fuel Used


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Although, electrical energy is a limitedcommodity, consumers can enhance its usage byapplying energy management (EM) strategies.

Definition: EM is a set of activities, which aim toreduce or shift electricity use to improve systemreliability and manage electricity costs (Bjorke,1986).

The aim of this research is to analyze the potentialareas for electrical EM in the mining sector, andhighlight it as a challenge to the utility industry aswell as to the end user.


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Introduction

Background of Mining Sector of

Ghana


Energy Management PrinciplesCase Study

Conclusions


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Minerals mined in Ghana include gold,manganese, diamond, bauxite, andlimestone.

Among the mining industries, gold miningcompanies dominate.

The four major gold mining companies in

Ghana, who account for over 90 % ofnational gold output (Hassan, 2008), areGoldfields Ghana Limited, AngloGoldAshanti, Newmont Gold Ghana Limited,and Golden Star Resources.


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Mining is closely associated with largeenergy (fuel and electricity) use.

According to Accenture (2003), energyaccounts for up to 35 percent ofoperating budgets in the mining andmetals industries.

Hassan (2008) also estimates that 7percent of electricity production in Ghanagoes to the mining companies of whichgold mining companies require in excessof 120 MW.


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Introduction




Case Study

Conclusions


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Energy management is the key to savingelectrical energy in an organization.

Much of the importance of energy saving stems

from the global restrictions on powerproduction, transmission and distribution.

This global need affects energy prices,emissions targets, and legislation, all of which

lead to several compelling reasons whyorganizations need to save energy.

Energy management is the means to controllingand reducing an organizations energyconsumption.


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Introduction






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The essence of EM is to enhance quality of powerwhile simultaneously reducing energy waste.

An EM plan should consider energy usage in all itsforms, its impact on the environment, and

importantly, the costs associated with its use.

EM is a logical, planned method of ensuringeconomic use of energy through a variety ofinitiatives, without affecting productivity andcausing inconvenience to staff.

A comprehensive EM plan should provide clearstrategies that will allow any organization to reduceenergy consumption through the formulation of anaction plan and effective supervision.


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Introduction






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Generally, the concept of energyconservation and management in industriesin Ghana is still at the developmental stage.

Case Study: AngloGold Ashanti, IduapriemMine.

The company has an organised energy dataon electricity usage.

The average total energy consumed by themine from January 2007 to January 2009 is7407.348 MWh.

M th GAG Sit T b bi Sit O l d Sit T t l E C d


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Month GAG Site

(MWh)

Teberebie Site

(MWh)

Overland Site

(MWh)

Total Energy Consumed

(MWh)

Jan-07 4975.5 522.9 199.0 5697.4

Feb-07 4152.7 522.9 169.6 4845.2

Mar-07 5169.4 539.4 81.7 5790.5

Apr-07 5748.3 489.8 169.5 6407.6

May-07 7001.2 490.2 179.2 7670.6

Jun-07 7183.7 535.8 83.9 7803.4

Jul-07 7706.2 555.9 94.7 8356.8

Aug-07 7809.0 489.0 96.8 8394.8

Sep-07 6795.7 406.2 80.0 7281.9

Oct-07 5692.7 405.9 72.6 6171.2

Nov-07 6697.0 490.8 90.3 7278.1Dec-07 7349.6 395.1 96.2 7840.9

Jan-08 7610.7 468.3 98.4 8177.4

Feb-08 6773.0 441.0 90.2 7304.2

Mar-08 7649.6 470.0 97.7 8217.3

Apr-08 7464.7 442.9 90.7 7998.3

May-08 7789.7 508.8 121.7 8420.2

Jun-08 7190.7 441.8 104.7 7737.2

Jul-08 7462.7 478.8 125.0 8066.5

Aug-08 7678.4 493.8 110.0 8282.2

Sep-08 7032.4 376.0 123.7 7532.1

Oct-08 7721.2 534.3 131.3 8386.8

Nov-08 7363.2 519.6 137.2 8020.0

Dec-08 6575.7 506.1 123.7 7205.5Jan-09 5663.6 514.0 120.0 6297.6


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The most dominant electrical load inmining industries is inductive.

Correct sizing of electrical appliancespresents another avenue to reduceenergy used.


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In the case of the Iduapriem mine, the ten pumps usedin the sumps are always in operation.

It has been established that most of these pumpsremain in operation even when there is no water in thesumps, which are characterised by high levels ofenergy wastage.

The motors running these ten pumps are all oversized.

The use of level switches to detect the level of water inthe sump to determine when to switch the motor on/offwill help to save energy.


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The main plant is composed of inherentlyenergy consuming loads (thus poor powerfactor).

Motors that are more efficient can replace oldmotors.

Also efficiency of any motor can be improvedthrough better controls and maintenance.


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The major uses of electrical energy in buildings are forlighting, cooling, and power delivery to office appliances.

Lighting is the most obvious source of energy wastage.

More sport lights should be used in the work shop.

Use of natural illumination should be enhanced.

Finally, cooling systems must be used judiciously toenhance EM.

Institutions can plant shading trees around officebuildings to give natural cooling effect and thus help inthis regard.


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Introduction






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This paper presented a general overview of EMand its implementation in the mining industries ofGhana.

Energy accounts for 35 percent of the operatingbudget in mining industries and seven percent ofthe electricity produced in Ghana goes to themining industries, of which gold mining companiesrequire in excess of 120 MW.

The global need to save energy will help reducedamage to the environment due to pollutantsemitted from the thermal plants.


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There is a great potential for energy conservationin the mining industries because the mostdominant electrical loads are inductive andoversized motors account for the most losses.

Notable places for energy conservation in themining industries include the sump, main plantand office complex and plant workshops.

Implementing EM measures will increase theinitial installation cost but there will be immensesavings in the end.


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Efficient Electrical Energy Management in the Mining Industries 1

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