POWER October 2016 - 53

GENERATION TRANSITIONS
crucial mineral industries output, reduced
demand to the point where Eskom was able
to avoid new rolling blackouts. But last year,
with world demand for minerals rising, and
after a collapse of the coal storage silos at a
major power plant in 2014, rolling blackouts
reappeared. Eskom beefed up its maintenance
program and also worked with the municipalities
that distribute much of its power
to reduce meter bypass and power theft.
According to the most recent update by
Molefe, " Energy availnew
CEO Brian
ability reached record highs of 81% for the
month of June. This was last achieved in
July 2013. " He added that " Eskom has been
able to meet demand this financial year even
during the week where demand was higher
than last year. " Except for 2 hours and 20
minutes, noted Molefe, " No load shedding
has been implemented since August 2015. "
Eskom also was able to cut output from its
diesel-fired gas turbines from 1,801 GWh to
16 GWh, slashing its expenditures for diesel
fuel by 98%.
The utility and its critics disagree over how
to credit the recent increased reliability. Eskom
points to the utility's actions. The Mail
& Guardian newspaper disagrees, commenting,
" But, when it comes to Eskom, even such
seemingly good news can be bad. Industry experts
say the reprieve the power grid and the
utility have been afforded is largely compliments
of an economy in the doldrums. "
The newspaper quoted " an independent
energy consultant " saying that " what we are
seeing are the effects of a rather deep downturn
in the economy. ArcelorMittal South
Africa has closed some mills; Lonmin is not
producing in many of its mines, Highveld
Steel shut down. Thousands of megawatts
have become available. "
Eskom's Matshela Koko, group executive
for generation, rejected that analysis.
" There should be no denying of the fact that
Eskom performance has improved over the
last 10 months, " he said. " This performance
improvement is easily visible to the naked
eye, but not to ideologues in whose eyes a
state-owned company is incapable of delivering
basic services as effectively as Eskom
currently does. The improved performance is
a result of strong leadership from the top and
hard work by Eskom employees. "
Koko added, " The assertion that it is not
Eskom's performance but rather the economic
slowdown that has kept the lights on
for the past 10 months is disputed. The facts
speak for themselves. The peak demand so
far in 2016 was 34,899 MW, which is 418
MW higher than peak demand experienced
in 2015. To put this in context, 418 MW is
almost equivalent to one unit at the Kriel
[coal-fired] power station. Peak demand for
October 2016 | POWER
Eskom's Generation Profile
Coal remains king at South Africa's Eskom.
The utility has about 39 GW of coal-fired
capacity at 14 generating stations, producing
over 80% of the utility's power. The
largest is the 3,990-MW Matimba plant in
Limpopo province, the largest dry-cooled
power station in the world, according to
Eskom.
Hydro has long been an important component
of Eskom's generating mix. The
utility has two conventional hydro generating
projects, Gariep (360 MW, Figure
2) and Vanderkloof (240 MW), both on
the Orange River, the largest river in the
country. Both were developed in the early
1970s. Eskom also has run-of-river hydro:
the 42-MW Collywobbles plant, the 6-MW
First and Second Falls project, and the
2-MW Nicora project. Pumped storage is
part of Eskom's hydro portfolio, with the
1,000-MW Drakensburg and 400-MW Palmiet
projects in service.
Eskom owns and operates Africa's only
nuclear plant, the two-unit, 1,800-MW
Koeberg plant, employing pressurized water
reactors on the Atlantic coast some 20
miles north of Cape Town. Construction
began on the French-designed units in
1976. The first unit went into service in
1984 and the second in 1985. In 2014,
Eskom awarded Areva a R5 billion (about
$385 million) contract to replace the aging
plant's steam generators in 2018. But
Westinghouse has challenged the contract.
Eskom documents indicate that the
steam generator job is on hold (see sidebar,
" Suspended! " ).
In 2004 the utility decided to add open
cycle gas turbine capacity to meet anticipated
winter 2007 peaks-largely because
turbine plants can be constructed faster
than other traditional options and can use
either natural gas or diesel. The nine-unit,
1,338-MW Ankerlig and five-unit, 746-MW
Gourikwa units came online between fall
2007 and early 2009. A corporate fact
sheet
notes that the units use diesel,
electricity in South Africa is during winter
and is driven predominantly by the cold
weather conditions. "
Work in Progress
Eskom is working to increase generating capacity,
with two major coal projects under
way. The utility also has two new pumped
www.powermag.com
2. Conventional clean energy.
This January 2011 shot shows the Gariep
Dam on the Orange River. Four 90-MW turbines
generate about 889 GWh annually.
The plant went online in 1971. Courtesy:
Aliwal2012, own work, Creative Commons
3. Turning point. Aside from a threeturbine
experimental wind-study facility
developed in 2003, the 100-MW-rated Sere
Wind Farm in the Western Cape of South Africa
was the first renewable capacity owned
by Eskom. It went into commercial operation
in 2015. Courtesy: World Bank Group
" trucked in from a supplier in the Cape
Town area " but can be converted to combined
cycle operation " should natural gas
be found in any major quantities on the
West Coast. " The company also has two
171-MW kerosene-fired plants, Acacia and
Port Rex.
Eskom has one wind project, the 100MW
Sere Wind Farm, which went into service
in the Western Cape province in 2015
(Figure 3). It uses Siemens turbines and
was financed by the World Bank Group.
As of March this year, Eskom's total
nominal capacity was 42,710 MW (total
installed capacity of 45,075 includes the
wind farm and hydro capacity run by the
Renewable Energy Division).
storage projects in the works, although one
is on hold.
Eskom is building the six-unit, 4,800-MW
Medupi supercritical coal-fired plant; the
first unit, Unit 6, was commissioned in 2015.
The utility announced the plant in 2007, at an
estimated price tag of R80 billion (roughly
$6 billion). The most recent cost estimate is
53
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POWER October 2016

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