Glossary of terms

AEL – Atmospheric Emission License

Available Dispatchable Capacity (Incl Non-Comm Units)
 – The capacity that is available from all dispatchable generation resources, and includes non-commercial generation, as it is dispatchable energy available to support the system.


CO2
 – Carbon dioxide 


CSP
 – Total contracted Concentrated Solar Power generation.

DEA
 – Department of Environmental Affairs

DEFF
 – Department of Environment, Forestry and Fisheries (Ministry)

Dispatchable IPP OCGT
 – OCGT plant that is owned by an IPP and is dispatched by Eskom National Control.

EAF
 – Energy Availability Factor of Eskom plant. It is the difference between the maximum availability and all unavailabilities (PCLF, UCLF & OCLF) expressed as a percentage. This excludes renewables, IPPs and international imports.

ESP
 – Electrostatic Precipitator

FGD
 – Flue gas desulphurisation

Financial Year
 – This is Eskom’s financial year, which starts from 01 April until 31 March of the following year. In some instances, data is shown for full weeks. In these cases, the period will start on the closest Monday to 01 Apr, and ends on the closest Sunday to 31 March. 

Gen Unit Hours
 – The amount of hours that one unit at pump storage stations can generate based on the amount of water still available in the dams or the number of hours that one unit at an OCGT power station can generate based on the fuel available at that power station. 

GT 
– Gas Turbine. Generation from small gas turbine power stations, and sent-out onto the Transmission network.

GW
 – Gigawatt = 1 000 megawatts

GWh
 – Gigawatt-hour = 1 000MWh

Hydro Generation
 – Generation from large hydro power stations, and sent-out onto the Transmission network.

ILS
 – Interruptible Load Shed. This is consumer load(s) that can be contractually interrupted without notice or reduced by remote control or on instruction from
Eskom National Control. Individual contracts place limitations on usage.

International Exports
 – Energy that is exported from RSA to neighboring countries.

International Imports
 
– Energy that is imported into RSA from neighboring countries.

IOS
 
– Interruption of Supply. It is all contracted as well as mandatory demand reduction resources utilised by Eskom National Control. This includes interruption of supply due to Transmission network faults. 

IPP
 
– Independent Power Producers that Eskom has contracts with.

kt 
– Kiloton = 1 000 tons

kV
 – Kilovolt

kWh
 – Kilowatt-hour = 1 000 watt-hours

kWhSO
 – Kilowatt-hour sent out

LNB
 – Low NOX Burner 

Load Factor 
– The ratio of the energy generated over a specific time versus the maximum generating capability over the same period.

MES
 – Minimum Emission Standards (published under the National Environmental Management: Air Quality Act (NEM:AQA) (Act No 39 of 2004)

MLR
 – Manual Load Reduction. It is an estimation of the demand that has been reduced due to load shedding and/or curtailment.

Mt
 – Million tons

MW
 – Megawatt = 1 million watts

MWh
 – Megawatt-hour = 1 000kWh

MWhSO
 – Megawatt-hour sent out

NAAQS
 – National Ambient Air Quality Standards

NAQO
 – National Air Quality Officer
NEMA – National Environmental Management Act, 1998 (Act No. 107 of 1998) 

NEMAQA – National Environment Management: Air Quality Act, 2004 (Act No. 39 of 2004)

NO
 – Nitrogen oxide

NO2
 – Nitrogen dioxide 

Non-Dispatchable Conventional IPP 
– IPP that uses conventional fuel sources to generate energy. These IPPs are contracted with Eskom but not dispatched by Eskom National Control.

NOX
 – Oxides of nitrogen (NOX = NO + NO2) 

Nuclear Generation
 – Generation from nuclear power stations, and sent-out onto the Transmission network.

OCGT – Open Cycle Gas Turbine. Generation from open cycle gas turbine power stations, and sent-out onto the Transmission network. These power stations use diesel as their primary resource.


OCLF
 – Other Capability Loss Factor of Eskom plant. It is the ratio between the unavailable energy of the units that cannot be dispatched, due to constraints out of the power station management control, over a period compared to the total net installed capacity of all units over the same period.

Other RE
 – Generation from other smaller contracted renewables (small hydro, biomass, landfill gas, etc.).

PCLF
 – Planned Capability Loss Factor of Eskom plant. It is the ratio between the unavailable energy of the units that are out on planned maintenance over a period compared to the total net installed capacity of all units over the same period.

PM
 – Particulate Matter

PM10
 – Particulate Matter with a diameter of less than 10μ

PM2.5
 – Particulate Matter with a diameter of less than 2.5μ

Pumped Water Generation
 – Generation from pumped storage power stations, and sent-out onto the Transmission network.

Pumping
 – During off-peak periods and when the system allows, water is pumped from the bottom dams at pumped storage stations to the top dams so that this water is available to generate with again. During this process, energy is used from the Transmission network.

PV
 – Total contracted Photovoltaic generation.

REIPP
 – Renewable Energy (RE) Independent Power Producer.

Residual Demand
 – The hourly average demand that needs to be supplied by all resources that can be dispatched by Eskom National Control. It includes Eskom generation, international imports, dispatchable IPPs and IOS. Normally expressed in MW.

Residual Energy
 – The total residual demand that is summated over a period of time. Normally expressed in MWh or GWh.

Residual Forecast
 – The forecast of what the expected residual demand will be in the future.

RSA Contracted Demand
 – The hourly average demand that needs to be supplied by all resources that Eskom has contracts with. It is the residual demand including demand supplied by self-dispatched generation (such as the renewables).

RSA Contracted Energy
 – The total RSA contracted demand that is summated over a period of time. Normally expressed in MWh or GWh.

RSA Contracted Forecast
 – The forecast of what the expected RSA contracted demand will be in the future. 

SCO
 – Synchronous Condenser Operation. The energy used (MW per hour) to overcome the frictional losses when plant is used to assist in stabilizing the network by supplying or absorbing reactive power.

SO2
 – Sulphur dioxide 

Thermal Generation
 – Generation from coal fired power stations, and sent-out onto the Transmission network.

Total Available Capacity (Incl Non-Comm Units and Renewables)
 – The capacity that is available from all generation resources that Eskom has contracts with, and includes non-commercial generation, as it is energy available to support the system.

UCLF
 – Unplanned Capability Loss Factor of Eskom plant. It is the ratio between the unavailable energy of the units that are out on unplanned outages over a period compared to the total net installed capacity of all units over the same period.

Wind 
– Total contracted Wind generation.

μ
m – 1 μm = 10-6 m