POWER October 2020 - 31

TOP PLANT
The Osman Khan, the latest in the
1. The Karadeniz Powership Osman Khan,
which has a capacity of 470 MW, supplied
450 MW to Tema, Ghana, burning heavy fuel
oil between 2017 and 2019. In late 2019, the
Powership was relocated to Sekondi Naval
Base, about 300 kilometers away on Ghana's
southern coast, where it continues producing
power using indigenously produced natural
gas. Courtesy: Karpowership
locked country, which received 10% of its
power from a Powership located in Nacala
for two years via a tripartite agreement
with Mozambique. Other countries include
Sierra Leone, Guinea, Gambia, Senegal,
Sudan, and Guinea Bissau (which
has received 100% of its power from a
34-MW Powership since February 2019).
Most have been delivered within 90 days
following financial closure.
A Focus on Flexibility and
Efficiency
However, the allure of a Powership is not
rooted in the " fast-power, plug-and-play "
aspect alone, as Harezi explained. Because
Karpowership fully executes all aspects of
a turnkey Powership project-starting from
design to delivery, including construction,
site preparation, commissioning, operation
and maintenance, and even fuel supply, if
requested-it has substantial control over
efficiency optimization.
" Because of our compact design and
seawater cooling [up to 10,000 cubic meters
a day can be desalinated depending on
the Powership model using evaporators],
we're even more efficient than land-based
power plants that can be constructed with
the same technology, " she said. And because
the ships are at sea level and contracts
are typically for baseload power,
production suffers minimal derating.
But flexibility, too, can be key to " ensure
the lowest cost of delivered power
with no capital outlay, " she noted. That's
why all but the first generation of the
company's Powership fleet use dual-fuel
engine technologies that can operate at
efficiencies of up to 51% in combined cycle
mode and consume a variety of fuels,
including low-sulfur HFO, natural gas, or
liquefied natural gas (LNG), she said.
October 2020 | POWER
" Khan " class, for example, uses 24
18.32-MW Wärtsilä engines and 30 MW
of steam turbines. Dual-fuel engines,
which Karpowership also sources from
MAN Diesel, offer specific advantages
for floating Powerships over gas turbines
because they are modular, and can provide
ancillary, black start, durability, voltage
and frequency control, and other
benefits, she said.
Flexibility, and specifically fuel flexibility,
is emerging as such an important
priority for some regions that Karpowership
has developed an offshore " gas-topower "
solution for its Powerships that
pairs the engines with a floating storage
and regasification unit (FSRU) to bridge
power gaps. The company is currently
working on converting two Powerships
currently deployed in Mozambique and
Senegal to LNG via its FSRU offering
over the first half of 2021, Harezi said.
" Our aim is never to profit from the
LNG molecules. We want to transfer
the lowest cost of molecules to the customer "
and give them more options, she
said. Even in countries that do not have
indigenous gas or large capacity requirements,
" LNG can be the perfect solution, "
she noted. " It is very compatible
and complimentary to renewables, as
well as baseload requirements. "
The Backbreaking Costs of
'Dumsor'
Karpowership's fuel flexibility was especially
a key consideration for Ghana.
However, ensuring the best use of the
resource proved costly. After decades
of reliance on the 1965-completed 912MW
Akosombo and the 1977-built 140MW
Kpong hydro plants, and owing to
a reduction in gas flows from Nigeria
due to unpaid debts, and transmission
losses, the government had struggled
to provide adequate power to its citizens.
Locals even coined a term for the
constant outages: " Dumsor. "
In 2015, Ghana moved to diversify its
power portfolio. In an effort to attract independent
power producers (IPPs), it
entered into long-term PPAs for 2.3 GW
with a " take-or-pay " clause-essentially
obligating the Ghana National Petroleum
Corp. (GNPC) to purchase 90% of a predetermined
quantity of gas produced from
the Sankofa offshore gas project, whether
it was able to use it or not. By the end
of 2018, the country expanded its power
portfolio to 19 power plants, nearly half of
which were developed by five IPPs. However,
only 3.9 GW was " dependable. "
www.powermag.com
POWER POINTS
Winning Attributes
✔ Providing Ghana with electricity
delivery options that furnished two
locations with power that was much
needed for growth.
✔ Inspiring an efficient, fuel-flexible
" plug-and-play " model that today
makes up a significant generation
component in many countries and
remote regions that lack power
infrastructure.
✔ Developing forward-looking
technology solutions to enhance
cost-savings, and promote energy
security and sustainability.
In mid-2019, finally, Ghana Gas, the
entity responsible for operating the infrastructure
required for the gathering,
processing, transporting, and marketing
of natural gas resources, completed the
required 11-kilometer gas pipeline from
a regulating and metering station in Takoradi
to the Sekondi Naval Base, where
the Osman Khan arrived from Tema and
was connected to the grid via a new 330kV
transmission line in September 2019.
As the Energy Commission noted last
year, while the Osman Khan's power
production with HFO at Tema was much
needed, it was expensive to fuel it. In
2019, Karpowership used about 2.3 million
barrels of HFO at an average delivery
price of $65.40 per barrel, the Ministry
of Energy noted. " With Karpowership
taking approximately 50% of the volume
of the take-or-pay Sankofa gas for power
generation over the remaining period of
the [PPA], Ghana will save a whopping
monthly take-or-pay cost of US $40 million
and projected annual savings of US
$480 million, " the ministry said.
Still, Ghana remains bullish on gas. The
growth of gas infrastructure, including
successful projects over the past year,
now leaves only one power plant-the
260-MW AKSA project-reliant on HFO.
" The use of natural gas helps bring down
the cost of electricity, saves our country,
and makes it possible for us to look at
a secure source of powering the transformation
of our country's economy and
for the industrial development of Ghana, "
noted President Nana Akufo-Addo in a
statement earlier this year. " That is our
main goal. " ■
-Sonal Patel is a POWER senior
associate editor.
31
http://www.powermag.com
POWER October 2020

Table of Contents for the Digital Edition of POWER October 2020
