POWER July 2023 - 16

PLANT OF THE YEAR
3. Getting Estrella del Mar III to its destination in Santo Domingo involved a 46-day journey. The
transportation route took the plant through the Strait of Malacca, a narrow stretch of water between
the Malay Peninsula and Indonesia, past a wide stretch of the Indian Ocean, and around
Africa, where it entered the Atlantic Ocean, and finally, the Caribbean Sea. The plant reached its
destination on Ocoa Bay on April 28, 2021, and it was commissioned on June 1, 2022. Courtesy:
ST Engineering
achieved by channeling the exhaust from
the gas turbine through the OTSG to generate
pressurized steam to run the steam
turbine. The re-using of exhaust heat energy
allows the steam-water cycle to produce
cleaner energy. At the same time,
it significantly improves the plant's overall
efficiency from 37% up to 56%, " it said.
Meanwhile, Siemens Energy's industrial
gas turbine engineering and manufacturing
team in Finspång, Sweden, and
the steam turbine innovation campus in
Görlitz, Germany, set to work to tackle
the power plant's weight and size. To fit
on a barge 80 m long and 35 m wide,
the power barge needed to be 50% the
size of a regular comparable plant. But
though optimized for weight and size,
Estrella del Mar III weighs 9,300 tons,
Siemens Energy noted.
Siemens Energy's solution was to
utilize first-of-a-kind single-lift package
designs. " It's the gas turbine, the gearbox,
and the generator, all [placed] on
one base frame, " noted Tyroller. " And the
same for the steam turbine, " he said.
Components from Siemens Energy's
production facilities were sent to Hamburg,
where they were placed on a base
frame and then shipped to Singapore as
" three big pieces instead of multiples, "
he said. At the shipyard in Singapore,
the modules were further combined as
blocks on land before being lifted onto
the barge (Figure 2).
The innovative design also features
a three-point mount. " If you build on a
floating device, you have to address the
challenge of motion-roll and pitch, as
well as accelerations and deflection, "
noted Hamed Hossain, business owner
of Siemens Energy's SeaFloat segment.
" The three-point mount foundation de16
couples
the deflection of the hull and the
gas turbine itself. " Hossain noted that the
plant is designed with a three-degree roll
and pitch limitation. " That means in case
the power plant and the motions would
be higher, we would need to shut down
[the gas turbine] for safety reasons. But
the risk is exactly the same like on a
land-based power plant, and we have our
very reliable T3000 [instrumentation and
control] system, where you monitor the
entire power plant also in regard to vibration
and so on. "
Despite the tight configuration to optimize
power density, the plant is designed
to facilitate operations and maintenance,
Hossain added. " There's enough space
available, " he noted. " The beauty is there
is a sliding concept that means you just
open the doors of the SGT-800 package,
slide out the gas turbine core, and bring
in, for example, a spare core into the
gas turbine package-which could take
around 48 hours maximum. So, the exchange
is very fast, " he said.
Overcoming a Series of Challenges
The biggest risk the project faced, according
to Tyroller, was from its transportation
from the shipyard 14,000 nautical
miles to its destination in Santo Domingo
(Figure 3). When it set sail in March
2021 after a short dry-docking onboard
a heavy-lift semi-submersible vessel,
the plant was only missing its final stack
piece. " The concept was totally new
for us, " Tyroller noted. " It's the biggest
stress on the equipment because that's
where you have the [most] motion, going
overseas. At the final destination, where
it's a river, it's fairly calm, " he noted.
Compounding the challenge was
working within the limited time that the
www.powermag.com
4. Estrella del Mar III's arrival in the vibrant
city of Santo Domingo, the Dominican Republic's
capital. Courtesy: Siemens Energy
team had access to a dry-tow vessel,
which tugged the barge to its final site.
" The difficulty with a dry-tow vessel is
you have to book it well in advance to get
a window, and when they show up, you
better be ready, " said Tyroller. Dry-tow
vessels (Figure 4) are " very rare and very
expensive, so you could lose several
months if you miss it, " he said. However,
the 46-day journey was mostly smooth,
he noted.
Another insidious risk was posed by
the COVID pandemic. " Singapore was
shut down for many months, " Tyroller
recalled. " Then, at a certain time, you
could go in and get two weeks quarantine
in a hotel room. So, getting people
there and equipment there was incredibly
difficult during those times. "
Hot commissioning of the first-of-thekind
project also furnished the project with
new challenges. During commissioning,
two hurricanes passed closely in the Caribbean
Sea, though the plant suffered no
damage. The global supply chain crunch
exacerbated by the Russian-Ukraine war
in early 2022, meanwhile, rendered new
difficulties to replace the project's first-ofa-kind
gearboxes owing to a shortage of
cargo planes. The delays were costly, but
the effort paid off immensely.
" As a consortium, we always have
the common goal in mind-to deliver
the SeaFloat to Seaboard and show how
we can make a difference, " said Tyroller.
" This is a groundbreaking project for us,
which has now been transferred to commercial
operation. Together with our customer
and partners, the entire team has
shown immense strength and perseverance
throughout the project, through the
various phases. We should all be proud of
this common success and celebrate this
great achievement of our first highly efficient
hybrid power barge. " ■
-Sonal Patel is a POWER senior
associate editor.
POWER| July 2023

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POWER July 2023

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