Power October 2022 140th Anniversary Supplement - 21

GAS TURBINES
How Gas Turbine Technology Is
Leading the Way to Net Zero
Gas turbines have come a long way since the first design to produce a positive power
output was constructed in 1903. Today, models with simple cycle capacities greater than
410 MW are available with combined cycle efficiencies greater than 64%. Furthermore,
there are good reasons to be optimistic about even more advanced technology in the
future.
Kennedy Maize and
Aaron Larson
T
he
Greek
power
system
provides
an interesting energy transition
case study. Lignite, the lowest-ranked
coal in terms of heat content,
was for many years the leading source of
power generation in Greece. In fact, the
International Energy Agency (IEA) reports
that nearly 72% of Greece's electric power
was generated from lignite in 1990.
Like many countries around the
world, the Greek government has acted
in response to climate change to reduce
carbon dioxide emissions, and lignite is
a prodigious producer of these. Therefore,
Greece aims to eliminate most lignite-fired
power plants by 2023, and all
units by 2028.
Greece has made great strides in
reducing its lignite usage. The IEA says
only about 13% of Greece's electric
power generation came from lignite in
2020, while natural gas, which accounted
for less than 0.3% of generation in
1990, supplied almost 39% of Greece's
power in 2020.
Adding a State-of-the-Art Gas
Turbine
In an industrial area in northeastern
Greece, a power plant is under construction
that exemplifies just how and
why gas turbine technology is supplanting
coal, both economically and to the
benefit of the environment. It is the Komotini
plant, a gas-fired combined cycle
plant, producing power from a Siemens
Energy SGT5-9000HL gas turbine, coupled
with a heat recovery steam generator
(HRSG), to produce 877 MW
of electric power. It's notable that the
Siemens Energy gas turbine has an
efficiency of up to 64%, compared to
lignite plant efficiencies that often have
percentages in the low 30s.
Construction on the Komotini project
started in 2021, and the station is scheduled
to enter commercial operation
in 2024. The heart of the project-the
SGT5-9000HL gas turbine-is an advanced
air-cooled, heavy-duty machine
launched by Siemens Energy in May
2020. The first 50-Hz SGT5-9000HL gas
turbine was delivered by Siemens Energy
to the Keadby 2 combined cycle
power project in the UK (Figure 1).
Replacing high-emission coal with
cleaner gas-fired generation is a logical
step in the energy transition, while not
forestalling the growing share of renewable
energy. The Komotini plant is expected
to reduce annual CO2
emissions
1. Keadby 2's SGT5-9000HL gas turbine is
shown here being delivered to the combined
cycle project's site in the UK. Courtesy:
Siemens Energy
October 2022 | POWER Supplement
by up to 3.7 million tons compared to a
conventional Greek lignite plant.
Other benefits of relying on gas power
through the energy transition revolve
around its load balancing and dispatch
capabilities, something lacking in most
renewables and nuclear power. Furthermore,
many gas turbine manufacturers,
including Siemens Energy, are developing
upgrades to designs that will allow
using e-fuels in the future, such as
100% hydrogen (H2
), which means generating
companies can avoid burdening
customers with stranded assets.
www.powermag.com
2. Siemens Energy's HL-class consists of
two engines: The SGT5-9000HL for 50 Hz,
and the SGT6-9000HL for 60 Hz. A modular
design approach allows for a substantial
number of common parts. The HL-class is
designed for high operational flexibility. Courtesy:
Siemens Energy
Derived from proven Siemens Energy
H-class technology (see sidebar),
the SGT-9000HL (Figure 2)-available
in both 50-Hz and 60-Hz models-is
the most powerful gas turbine design
available from Siemens Energy's extensive
gas turbine portfolio. In fact,
Duke Energy announced on Aug. 23,
2022, that its Lincoln Combustion Turbine
Station in North Carolina, powered
by the first 60-Hz SGT6-9000HL,
which Siemens Energy delivered to the
site in November 2019, has been certified
with the official Guinness World
Records title for the " most powerful
simple-cycle gas power plant " with an
output of 410.9 MW.
" The key to helping our customers
in the energy transition is not just by
providing high power output but doing
it with the highest efficiency and
flexibility possible. Our HL turbine,
with the benefit of advanced combustion
and
cooling
technologies,
leveraging additive manufacturing, advanced
coatings, and more, makes a
difference for customers and for the
environment. And the HL turbine can
ramp up quickly, to provide power to
the grid when renewables aren't availPAST,
PRESENT & FUTURE 21
http://www.powermag.com
Power October 2022 140th Anniversary Supplement

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