POWER SUPPLY: Eskom Cape Beavering Ahead
Recent Western Cape Business News
MENTION Eskom and most all thoughts go the recent management upheavals and the steep price increases predicted over the next couple of years.
Security of supply is also of concern, yet the truth is that Eskom has done much to ensure that there is adequate supply of electricity in the Western Cape since the province experienced load shedding in 2008.
The Western Cape has various power plants to ensure the stability of the network and preventing the reliance of electricity needs from the North, the company says.
Koeberg Nuclear Power Station, the only nuclear power plant in Africa, produces 1 800 MW which forms part of the base load for the Western Cape. Situated in the West Coast, Koeberg Nuclear Power Station uses sea water for cooling purposes.
The Western Cape has a further three peaking generation power plants, one pumped storage scheme in Grabouw called Palmiet (400 MW), one gas station (150MW) and two open cycle gas turbines (2 083MW).
A further 2 400 MW can be transferred from up north using the transmission lines. In total, the Western Cape has 6 046 MW to meet its demand of 4 250 MW in winter and 3 900 MW in summer.
Eskom is currently working on strengthening the transmission lines of 400 KV lines to 765 KV lines, thus allowing for an additional 100 MW to be transferred via the transmission lines. The two open gas cycle turbines projects were built in just less than 18 months, a tremendous achievement considering that power stations of this nature are built in five years or more. They were built to form part of peaking stations to assist during evening peaks and thereby reducing the load on the transmission lines. They can also be used during emergencies when Eskom loses all supply on the lines and the Cape islands, to quickly recover.
Local generation comes in the form of the following power stations:
• Koeberg Nuclear station (for base load, 2 x 900MW);
• Palmiet pumped storage station (peaking station total 400MW),
• Two injections at Hydra namely VanderKloof (2x120MW units) and Gariep (4x90MW units). These hydroelectric power stations depend on the availability of water in the Orange River.
• Port Rex gas turbines in East London normally run in synchronous condenser mode for voltage support.
• Acacia gas power station (total of 3 x 57MW units with at least one unit dedicated for emergencies at Koeberg power station at any given time). Acacia power station also runs in SCO mode whenever additional MVAr support is required.
• Ankerlig Power Station (OCGT) > 9x150MW.
• Gourikwa Power Station (OCGT) > 5x150MW.
The 3x57MW unit Acacia power station dedicates two units to Koeberg power station for emergency supply. This serves to supply the auxiliary equipment during major outages (e.g. loss of second Koeberg generator during the refueling of the first unit). Palmiet power station has a capacity of 400MW (2x200MW units) and provides support especially during outages of Koeberg generators and high-load periods. Gariep and VanderKloof power stations have a full capacity of 600MW but normally run on an average combined output of 300MW – only average output has been simulated for these power stations for planning studies. Water availability often limits the output of Gariep and Van der Kloof hydro stations.
The new gas power stations (Ankerlig at Atlantis and Gourikwa at MosselBay) are used for supply peak demand and they are used continually in SCO (Synchronous operation) mode on a regular basis.
In December 2007 the Eskom Board approved the Cape Corridor 765kV Strengthening which will be fully commissioned by early 2011.
Eskom is currently building Tafelbaai Substation near Cape Town to be fully commissioned this month. This substation is specifically for 2010 strengthening which will provide much improved reliability of supply to the City centre and the Waterfront.
The new increased capacity will reduce the risks during peak load times. Eskom has invested approximately R285 million to ensure the reliability of supply in the city centre and its surrounding areas for 2010 and beyond, it points out.
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