pwr_july-2024 - 28

HYDROPOWER
Hydropower Remains Renewable
Leader Despite Climate Challenges
As the oldest renewable energy resource, hydropower is well-established as a reliable
source of dispatchable energy. Yet, it is often overlooked and taken for granted. It's
commonly believed that hydro's potential is tapped out in the U.S., but many
opportunities exist to add capacity at non-powered dams and on repowering projects.
Darrell Proctor
H
ydropower installations worldwide
have been increasingly impacted
by drought conditions. The World
Economic Forum in a recent report noted
that while hydro for many years has
provided most of the globe's renewable
energy, its output has slowed due to the
effects of climate change, including what
the International Energy Agency (IEA)
calls " erratic " rainfall. The IEA has said
global investment in hydropower generation
capacity has fallen in the past few
years, and the group expects that trend
will continue.
Despite that, new projects-including
large installations-are being built.
China and the U.S. in recent years have
experienced drops in the percentage of
hydro as part of those countries' generation
mix, but China for its part continues
to invest in hydroelectricity as part of that
country's strategy to increase all forms of
power generation. China is home to most
of the largest hydropower dams in the
world, led by Three Gorges Dam, a 22.5GW
behemoth that has produced power
since 2003. Next is the Baihetan hydropower
station (Figure 1), a 16-GW facility
that became fully operational in 2021.
Climate Change Impacts Hydro
Chinese officials, though, earlier this year
said the country's hydro generation has
been essentially flat for the past three
years despite several new large power
stations coming online, including the Lijiaxia
Hydropower Station No. 5, one of
the world's biggest hydropower plants
in a dual-row turbine layout. That facility
entered operation in October of last year.
Officials in China have acknowledged the
need to continue to support hydropower,
even as prolonged drought has markedly
reduced river flows in the southwestern
part of the country.
" Hydropower generation critically depends
on how much water runs in rivers
and hence hydro climatological conditions.
In the decades to come, there are
likely more frequent and severe droughts
globally, threatening sustainable hydropower
operations and installations, " said
Dr. Hong-Yi Li, associate professor of
1. Chinese officials said the Baihetan Hydropower Station, the world's second-largest hydro
dam with 16 GW of generation capacity, represents an investment of about $34 billion. Courtesy:
China Three Gorges Corp.
28
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civil and environmental engineering at the
University of Houston. Li told POWER,
" To tackle this challenge, other forms
of renewable energy such as solar are
worthy of more consideration than ever,
particularly for those places that already
often experience water shortages. " China
has certainly recognized this; the country
added 226 GW of new power extra generating
capacity last year, with 129 GW
from solar, 39 GW from thermal, 33 GW
from wind, and 8 GW from hydro, according
to the National Energy Administration.
Dimitrios Kalliontzis, assistant professor
of civil and environmental engineering at
the University of Houston, told POWER:
" Hydropower accounts for more than 25%
of the renewable electricity generation in
the United States. The risk hydropower
is facing underlines the need to rethink,
adapt, and transform. While drought is
a threat to hydropower facilities, climate
change and the associated sea level rise
may create opportunities to adapt existing
technologies to the offshore marine
environment, harvesting tidal streams,
currents, or even waves. While offshore
harvesting is still in the early stages, it can
potentially compensate or exceed the current
hydropower supply. "
Ember, an energy think-tank based
in the UK, last year reported that global
output of hydropower had a historic drop
in the first half of 2023. The group said
drought conditions led to an 8.5% decrease
in global hydro output during that
period; China accounted for about 75% of
the worldwide decline. The IEA has said
hydropower eventually will be overtaken
by solar and wind energy output, though
the agency doesn't expect that to happen
for at least another decade. The group
said a slowing of the industry's growth
puts global net-zero targets in jeopardy.
The International Renewable Energy
Agency reported that hydropower generation
capacity must double by 2050 for
the world to remain on track to limit global
warming to 1.5C by mid-century.
POWER | July 2024

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