Overview of Eskom’s System Operator

Presented by: Mr Bernard Magoro

Date: 7 June 2018

What is the System Operator?

Generation makes

the electricity

Transmission & Distribution transports the electricity

Customer Services

sells the electricity

System Operator ensures

continuous delivery of quality

electricity by maintaining a stable

Grid

The System Operator is

the electricity transport

and distribution

supervisor.

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Eskom Grid in relation to Europe

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Provincial demand at time of System Peak (30 May 2017)

Province Provincial demand at time of

2017 System Peak

Eastern Cape 2 367 MW

Free State 1 132 MW

Gauteng 10 900 MW

KZN 6 630 MW

Limpopo 2 260 MW

Mpumalanga 4 710 MW

North West 3 805 MW

Northern Cape 714 MW

Western Cape 3 095 MW

10 900

1 132

2 367

6 630

2 260

4 710

3 805

714

3 095

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National Control • 765 kV – 132 kV

• Frequency control

• Voltage control

• System security

Regional Control • 132 kV – 66 kV

• Voltage control

• System security

Regional Control • 66 kV – 11 kV

• Customer supply

Hierarchical control responsibility

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49.5

50.0

50.5

Generation Load

Generation output is changed every 4 seconds to match customer demand.

When there is insufficient generation available, customer demand is

reduced to ensure system stability is maintained.

Balancing supply and demand in Real-Time is the critical role of the SO

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Cold weather can cause up to a

10% change in the load.

Accurate demand forecast is key in the planning phase

When Gauteng becomes

overcast during the day, the

demand increases by up to

1200 MW (nationally). This

includes the Solar PV effect.

The Eskom forecast considers a

multitude of factors, but weather

and the economy are the most

dominant factors.

• Season

• Day of week

• Public holiday

• School holiday

• Strikes

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Cost of generation

Demand forecast

Unconstrained

schedule

(Cheapest mix)

Network constraints

Day ahead contract

Generation scheduling process

Operating reserves

Renewable forecast

Unconstrained schedule

(Least cost)

Constrained schedule

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Installed Generation Resources (by Technology) (January 2018)

Type Number Nominal capacity

Coal-fired 15 stations 38 023 MW

Gas/liquid fuel turbine 4 stations 2 409 MW

Hydroelectric 6 stations 661 MW

Pumped storage 3 stations 2 724 MW

Nuclear 1 station 1 860 MW

Wind energy 1 station 100 MW

Total Renewable IPP 64 stations 3 811 MW

Total IPP Gas 2 stations 1 010 MW

Wind IPP 22 stations 1 998 MW

Solar PV IPP 33 stations 1 482 MW

CSP IPP 4 stations 300 MW

Total Eskom 30 stations 45 777 MW

Small Hydro IPP 2 stations 14 MW

Landfill IPP 3 stations 17 MW

Biomass IPP 0 stations 0 MW

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Station build-up for a typical day demand profile

To meet the peak ,resources utilised were as follows ,Eskom(including HCB) 34070

MW, 439 Renewables IPPs and 344 VPS. No Eskom and IPPs Gas was utilised

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Seasonal and weekly demand profiles

• Outages are planned around the peak demand

• The summer load profile is a lot “flatter” than the winter profile

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Annual Demand Profile

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25000

27000

29000

31000

33000

35000

37000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53

Website Demonstration: Eskom weekly system status report

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Enquiries:

Mediadesk@eskom.co.za

+27 011 800 6050 / 3343 / 6103

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