POWER October 2014 - 26

TOP PLANTS
Prefecture (see " Does IGCC Have a Future? "
in the July 2014 issue).
As part of its goal to maintain a modern,
balanced generation portfolio, TEPCO in the
late 1990s chose a site in the village of Tokai
in Ibaraki Prefecture for its newest, most advanced
coal plant. Construction of Hitachinaka
Thermal Power Station (HTPS) Unit 1
began in July 1999. The plant was built on reclaimed
land in a section of the North Wharf
of Hitachinaka Port.
Built by Hitachi's power generation division
(now part of Mitsubishi Hitachi Power
Systems) the 1,000-MW USC plant employed
a variable-pressure, spiral-wound Benson
boiler supplied by Babcock-Hitachi K.K.
and equipped with Hitachi's newly designed
low-NOx NR-3 burners and advanced steam
temperature controls. To enable the plant to
fire a variety of coals, superheater attemperators
were installed between each superheater
section. To meet strict national environmental
regulations, the plant was equipped with a
flue gas denitrification system (supplied by
Hitachi) and a desulfurization system and an
electrostatic precipitator (the latter two supplied
by IHI). The plant was also equipped
with a fully digital large-scale monitoring
system.
At the start of commercial operations in
December 2003, Unit 1 achieved one of the
highest efficiencies of any coal plant in the
world: 45% LHV.
TEPCO's plans for HTPS included future
expansion, and space was left adjacent to
Unit 1 for another unit. Planning for it began
not long after Unit 1 came online, and
construction began in October 2009. After
competitive bidding, Hitachi was again chosen
to lead construction and supply the major
components, with Babcock-Hitachi K.K.
also supplying the boiler. Like its sister unit,
Unit 2 would employ an USC variable-pressure
boiler, but Unit 2 also would include a
low-pressure turbine using the same 41-inch
blade design used in Unit 1's high-pressure
turbine.
A Major Shake-Up
Construction of Unit 2 was proceeding on
schedule in March 2011 with framing of the
boiler and turbine buildings under way.
At 2:45 p.m. Japan Standard Time on Mar.
11, a roughly 300-mile-by-120-mile section
of the subduction zone offshore of northern
Japan ruptured. The epicenter of the resulting
9.0 magnitude earthquake-the largest quake
ever recorded in Japan and the fifth-largest
recorded quake in modern history-was just
155 miles northeast of the plant site.
More than 15,000 people across Japan lost
their lives in the earthquake and subsequent
tsunami, and the economic losses have been
26
estimated by the World Bank at more than
$230 billion. Though Ibaraki Prefecture did
not sustain the widespread devastation experienced
by the Tohoku region farther north-
in part because it did not suffer as heavy an
inundation from the tsunami-the damage
was still enormous. Though only a few dozen
lives were lost, tens of thousands of buildings
were destroyed or heavily damaged. Peak
inundation from the tsunami was recorded
at 13.7 feet at the town of Oarai a few miles
south of HTPS.
HTPS suffered substantial damage from
the quake and flooding (Figure 1). Unit 1
tripped offline when the quake struck, but
the impact was only beginning. Because the
site was on reclaimed land, it suffered serious
liquefaction, causing elements of the
plant to sink into the soil. Four workers at the
construction site fell to their deaths when the
scaffolding they were working on collapsed
underneath them. The coal-unloading terminal
suffered heavy damage, with the main
crane toppling over and the coal conveyer
belt knocked out of service because of liquefaction
of the ground underneath. Much of
the site was left under water even after the
tsunami receded.
Construction of Unit 2 had to cease as the
plant, and the nation as a whole, struggled to
recover from the disaster.
More than 4 million people in Japan had
lost electricity, and TEPCO saw approximately
25% of its generating capacity knocked offline.
While most of the world's attention was
focused on the damaged nuclear plants to the
north, the crews at HTPS shifted from construction
to repair in order to get the plant's
critical generation back into service.
Despite the heavy damage, Unit 1 returned
to operation in just two months, restarting
on May 15. Though the coal transfer
equipment was still damaged, crews were
able to supply fuel to the plant with some
creative measures. With the coal-unloading
crane still out of service, coal was delivered
by bulk carriers equipped with their own
cranes. The coal was unloaded into trucks
instead of onto the conveyer, and the trucks
delivered the coal to a hopper that then fed
it into the plant. To support plant reliability,
this operation ran 24 hours a day.
Construction of Unit 2 resumed in late
May. The disaster had caused a two-anda-half
month delay in the schedule, but the
now-urgent need for new generation because
of the nationwide nuclear shutdown meant
the plant had to be completed as soon as
possible. TEPCO staff and the construction
crews worked around the clock to get things
back on track, and amazingly, despite the incredible
upheaval caused by the earthquake,
Unit 2 was finished and put into commercial
www.powermag.com
operation on schedule on Dec. 18, 2013, after
51 months of construction.
Running Smoothly
Unit 2 has performed as expected since
coming online, even during periods of peak
summer demand. It has achieved one of the
world's highest thermal efficiencies, 45.2%
LHV, for coal-fired thermal power stations,
according to a TEPCO statement.
TEPCO, though, is not standing still. It announced
shortly before Unit 2 came online
that it had agreed with Chubu Electric Power
Co. to build a third, albeit slightly smaller
(600 MW) USC unit at the HTPS site. That
unit will be 96.55% owned by Chubu Electric
and 3.45% owned by TEPCO. Construction
is planned to start in 2016, with operation
slated for 2020. ■
-Thomas W. Overton, JD is a POWER associate
editor (@POWERmagazine,
@thomas_overton).
POWER | October 2014
1. Walloped. The Hitachinaka Thermal
Power Station suffered heavy damage from
the March 2011 earthquake and tsunami, with
its coal transport system knocked out of service
and much of the site flooded, as these
images show. Courtesy: TEPCO
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POWER October 2014

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