POWER October 2014 - 33

TOP PLANTS
1. Vital partner. The captive plant at Jharsuguda powers an adjacent 0.5-mtpa aluminum
smelter. Courtesy: Sesa Sterlite LLC
projects despite government efforts to relax
capital requirements for bidding.
The nation has also struggled with its transmission
infrastructure. The widely publicized
blackouts in July 2012 that knocked out power
for more than 60% of India's population, including
most of Odisha State, were blamed
on inadequate interregional transmission and
poor grid management. Nationwide, transmission
losses are estimated to be about 24%, according
to India's Central Electric Authority,
well above levels in developed countries.
Vital Operations
Aluminum smelting is one of the most power-intensive
industrial processes. The primary
method used, the Hall-Héroult process, involves
heating a mixture of aluminum oxide
and other compounds with electric current
in a smelting cell until the molten aluminum
separates out. Not only does this method consume
enormous amounts of electricity, but
the cells also must be continually heated or
the mix of materials will solidify and the cell
will be useless until repaired. This means a
power loss across an entire plant could spell
disaster, which is why aluminum smelters are
typically located near large power plants.
London-based Vedanta Resources is a
globally diversified natural resources company
with operations in India-where it is
the nation's largest mining firm-Australia,
South Africa, Namibia, and other countries.
Vedanta subsidiary Sesa Sterlite Ltd. (SSL)
is one of the country's largest commercial
power producers as well as a major natural
resources firm. Since the mid-2000s, SSL has
been developing a huge aluminum production
zone in Jharsuguda in the eastern state of
Odisha. Initial plans envisioned a 0.5 million
metric tons per annum (mtpa) smelter, to be
eventually expanded to 2.6 mtpa (Figure 1).
Odisha has abundant reserves of both bauxite
(aluminum ore) and coal. Phase 1 of the project,
comprising the 0.5-mtpa smelter, was
completed in 2009, while Phase 2, a 1.25mtpa
expansion, was completed in 2011.
October 2014 | POWER
Such a massive project would have equally
massive power demands, and relying on
the national grid for power, even if it came
from a nearby plant, would be risky. To ensure
reliable operations would mean building
a captive power plant to supply the project
directly. SSL soon drew up plans for what
would be the largest captive power plant in
the entire country.
Construction began in 2005, and the first
unit, Unit 3, came online in July 2008. The
last of nine units came online in early 2010.
The project was completed without a single
lost-time accident.
The plant consists of nine 135-MW subcritical
pulverized coal, single-reheat boiler
units, utilizing corner tangential firing and
natural circulation, supplied by Shanghai
Electric Co. Each boiler uses four bowl mill
pulverizers to prepare the coal for combustion.
The boilers are rated for 440 tons per
hour of main steam, at 2,070 psi and 1,005F
at the superheater outlet. Each boiler supplies
steam to a single double-cylinder, 39-stage,
double-flow, extraction and condensing
steam turbine.
The plant's environmental controls are
among the most advanced in India. Fly ash is
captured with electrostatic precipitators and
fabric filters and is recycled for use in road
construction and fill.
The plant is the first coal-fired unit in the
country to employ high-concentration slurry
disposal of dry and bottom ash. This system
combines both ash streams into a mostly
solid slurry to reduce water consumption and
fugitive dust, as well as requiring a smaller
footprint compared to conventional ashhandling
systems. The high concentration of
solids means the slurry forms a natural slope
in the disposal area without the need for mechanical
spreading.
The plant employs counter-flow forced
cooling towers and multi-flue stacks. Process
water is sourced from the nearby Hirakud
Reservoir, while coal is supplied from the
Mahanadi Coal Fields outside Jharsuguda.
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Exemplary Performance
Since coming fully online, the SSL's captive
power plant has received numerous honors
for excellence in operations and energy efficiency.
It has received the National Energy
Conservation Award bestowed by the Bureau
of Energy Efficiency in 2011 and 2012,
and in 2013 received both the Confederation
of Indian Industry's National Award for Excellent
Energy Efficient Unit and the India
Power Award from the Council of Power
Utilities. The overall Jharsuguda operation
was also honored for its commitment to sustainability
with a Green Manufacturing Excellence
Award from consulting firm Frost
& Sullivan.
These honors have come in large part from
the plant staff's relentless drive to improve
the plant heat rate and cut its fuel consumption.
The overall plant heat rate has been reduced
from 10,627 Btu/kWh in 2010 to 9,591
Btu/kWh in 2013, an impressive achievement
for a subcritical plant. Coal consumption has
been cut from 893 grams per kilowatt-hour
(g/kWh) to 806 g/kWh over the same period.
Environmental performance has also been
improved. Upgrades to reduce particulate
emissions have cut them from 181 mg/m3 in
2010 to under 30 mg/m3 currently.
The plant's biggest challenge, not surprisingly,
has been finding adequate fuel to
operate. To address its fuel challenges and
increased costs of imported coal, SSL has
begun blending and burning coal purchased
in spot-market auctions. This approach allows
it to balance its fuel costs depending
on the price of imported coal. Currently, the
plant burns up to 70% auction coal, and future
plans are to maximize this approach to
reduce overall fuel costs.
The plant has also gone beyond the call
of duty in other ways. Thanks to its reliable,
efficient generation, the adjacent 0.5-mtpa
smelter has been able to run above rated capacity
despite continuing difficulties with the
local grid. Meanwhile, the 1.25-mtpa expansion
has been unable to start up because of
ongoing disputes with the Odisha state government
over tariffs on the power it would
be using from SSL's 2.4-GW independent
power plant in the same industrial zone, but
because the captive power plant has a 100MW
surplus, Vedanta officials said in the
company's second quarter 2014 earnings call
that it plans to begin limited operations at the
larger smelter this year using power from the
captive plant.
For achieving exemplary performance in
a highly challenging environment, Sesa Sterlite's
captive power plant at Jharsuguda is a
deserving POWER Top Plant. ■
-Thomas W. Overton, JD is a POWER
associate editor.
33
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POWER October 2014

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