IEEE Power & Energy Magazine - November/December 2014 - 62

Natural gas presents utilities and energy planners
with a cleaner alternative to coal at around the
same cost.
however, coal units are being ousted gradually as an energy
resource due to their adverse environmental effects. The battle
on clean-energy choices is more or less won in the Western
Hemisphere, but that is not the case in regions experiencing
rapid and significant energy growth, like China and India.
Natural gas presents utilities and energy planners with a
cleaner alternative to coal at around the same cost. Low natural gas prices coupled with recent discoveries of abundant
shale gas reserves in various countries have made it an exciting time for energy production. Shale gas reserves have led to
a broad consensus that countries like the United States have
enough domestic supplies of natural gas to power their cities
for generations. In essence, residential and commercial heating demand for natural gas is highly sensitive to the weather,
making weather the biggest driver of natural gas demand in
the short term. As a result, natural gas demand is highly seasonal in nature, with significant peaks during the winter heating
months. The seasonal nature of heating demand can cause the
price of natural gas to vary widely at different times of the year.
This can be detrimental to the supply of natural-gas-fired units
as natural gas pipelines and distribution companies work to
meet residential customers' needs during peak demand periods.
Increasing supplies of natural gas may facilitate the integration of clean-energy technologies. Sunlight, wind, rain,
tides, waves, and geothermal heat are now used for electricity generation and can also provide a primary energy source
for a variety of applications, such as heating water and buildings, powering transportation vehicles, and serving rural areas.
Renewable energy sources are environmentally friendly, but
their intermittency is problematic. This is because these
sources may be uncontrollably variable during normal operating conditions. Solar energy can be generated only when the
sun is shining brightly; wind power plants are idle when there
is no wind blowing. These types of units cannot be optimally
dispatched or committed for purposes of economic operation.
Most natural gas plants, on the other hand, have the flexibility to quickly change their dispatch and can manage the
variability of renewable energy units. The ability to adjust
power production within minutes has key advantages for
both the integration of renewable energy sources and as a
reliable supply for meeting peak demands. Natural gas can
be dispatched flexibly, which offers more capacity for system reliability. The quick ramping capability of natural gas
generators makes them ideal for complementing variable
renewable generation. One important factor is the speed with
which natural gas plants can be started when demand is high.
Some natural gas turbines can cold-start in five minutes.
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This flexibility may generate additional value as new ancillary service products are designed to accommodate increasing levels of variable generation on the grid and new regional
capacity or other ancillary services markets are developed to
meet future reliability needs.
Pipeline availability and natural gas storage are required to
supply natural-gas-fired units. These allow natural gas plants to
be built close to population centers, which provides reliability
and economic advantages. Wind farms can only be built where
the wind is blowing, and these areas are often in remote locations that require additional investments in costly transmission
and distribution infrastructure. Renewables will continue to
increase their market share, and these clean-energy industries
will be critical for long-term global economic development.
A balanced electricity portfolio of fossil-fuel and renewable energy assets is likely, and the exact mix will depend on
resource availability, fuel costs, and emission requirements.

For Further Reading
The Republic of Turkey Prime Ministry Investment Support
and Promotion Agency. (2014, Mar. 24). Economic outlook.
[Online]. Available: http://www.invest.gov.tr/en-US/turkey/factsandfigures/pages/economy.aspx
Planning and Coordination Department of TEI˙AS¸. (2013,
Nov.). Five year generation capacity projection of Turkey
(2013-2017). [Online]. Available: http://www.teias.gov.tr
"Natural gas sectorial report," Head of NG market department, EPDK, Ankara, 2013.
O. Tanidir, O. B. Tör, and C. Gencoglu, "Performance of
short-term load forecasting with ANN in Turkish Power System," in Proc. IEEE PES General Meeting, San Diego, CA,
July 2012.
C. Liu, M. Shahidehpour, Y. Fu, and Z. Li, "Securityconstrained unit commitment with natural gas transmission
constraints," IEEE Trans. Power Systems, vol. 24, no. 3, pp.
1523-1536, 2009.
M. E. Cebeci, U. Karaag˘aç, O. B. Tör, and A. Ertas¸, "The
effects of hydro power plants' governor settings on the stability of Turkish Power System frequency," in Proc. IEEE PES,
ELECO, Bursa, Turkey, Dec. 2007.

Biographies
Osman Bülent Tör is with EPRA, Ankara, Turkey.
Mohammad Shahidehpour is with the Illinois Institute
of Technology, Chicago, and King Abdulaziz University in
Saudi Arabia.
p&e

november/december 2014

http://www.invest.gov.tr/en-US/turkey/fact http://www.teias.gov.tr

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