Georgia Magazine - June 2020 - 12

GEORGIA'S Energy Outlook

By David Gattie

Nuclear power: green and efficient

Georgia Magazine

June 2020

GEORGIA POWER CO.

he United States is having a debate over the
future of its electric power sector. And since
coal, natural gas, nuclear, wind and solar
power will be at the center of the debate, it's important to be informed about some basic differences
among these resources and their technologies.
In coal and natural gas plants, hydrocarbons
are combusted in an energy-conversion process
that drives a turbine to generate electricity. This
process produces emissions such as sulfur dioxide,
nitrogen oxide and particulate matter, which are
regulated and managed on-site by environmental
control technologies. Carbon dioxide is also emitted
but currently isn't regulated. Wind turbines require
high-speed winds to turn large blades connected to
a turbine-generator, whereas solar panels employ
photovoltaics (PV) to directly convert sunlight
photons into electricity. Lastly, nuclear plants
are driven by splitting atomic nuclei in a process
called fission, releasing energy that's used to drive a
turbine-generator.
Wind, solar and nuclear are zero-emission
technologies, with nuclear accounting for 55 percent
of zero-emission electricity in the U.S. What can
be mistaken for emissions are what appear to be
white clouds rising from cooling towers employed at
some nuclear plants to cool the water used in power
generation. However, this is pure water vapor-not
smoke, combustion byproducts or radiated gases.
One of the most important characteristics of
an energy resource is energy density, which is a
measure of how much energy is concentrated in the
resource itself. This has much to do with a technology's capacity to maximize the amount of electricity
generated from each unit of energy consumed.
For fossil fuel plants, 1 kilogram (kg) of coal
generates about 2.3 kilowatt-hours (kWh) of electricity, while 1 kg of natural gas generates about 6.8
kWh. For a typical U.S. nuclear plant, 1 kg of nuclear
fuel generates about 353,547 kWh of electricity.
Wind and solar have very low energy densities and
don't compare with coal, natural gas and nuclear on
a per-kilogram basis.
Since power plants are sized based on megawatts (MW) of generating capacity, they can be
compared based on the megawatt-hours (MWh) of
electricity generated for every MW of plant capacity.
Last year, U.S. nuclear power accounted for 809.4
million MWh of electricity from a capacity of

This aerial view shows the Alvin W. Vogtle Electric Generating Plant units 1 and 2
in Burke County near Waynesboro. Units 3 and 4 are under construction.

98,788 MW. This translates to 8,193 MWh of electricity generated for every
MW of installed capacity. The chart below compares nuclear power with
several other fuel sources.

MWh of electricity generated for every MW of installed capacity
Source

MWh generated

Nuclear power
Natural gas
Coal
Wind
Solar PV

8,193
4,976
4,102
3,073
2,168

While these differences partly reflect energy density, they also reflect
the annual capacity factor (ACF), or the percentage of a year that a power
generating plant is actually operating. For 2019, the ACFs were 24.5 percent
for solar, 34.8 percent for wind, 47.5 percent for coal, 56.8 percent for
natural gas and 93.5 percent for nuclear. The lower values for solar and
wind, can be attributed to the variability and intermittency caused by
weather, time of day and season.
Each of these fuel resources adds value to a power generation portfolio, but the one resource that exceeds all others in all categories is nuclear
power.
David Gattie is an associate professor of engineering at the University
of Georgia (UGA) in Athens and a senior fellow with UGA's Center for
International Trade and Security.

Georgia Magazine - June 2020

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