Science & Technology
April 27,
2022
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This undated photo provided by Consumers Energy shows an aerial view
of the Ludington Pumped Storage Plant near Ludington, Mich. Advocates
of pumped storage call such facilities the "world's largest
batteries." (AP Photo/Consumers Energy)
The United States hydropower
industry considers pumped storage the best answer to a
question surrounding renewable energy: where to get power when the sun
is not shining or the wind is not blowing.
But pumped storage faces an unclear
future. Even though experts predict growing demand for power storage,
the industry’s growth has slowed.
What is pumped storage?
Pumped storage is when water is sent from
a lower reservoir to an upper one, then released
downhill through large machines known as turbines.
Pumped storage dates from the early
1930s. But most systems were built many years later to hold
electricity from nuclear plants.
Supporters call these systems “the
world’s largest batteries” because they hold large amounts of energy.
The U.S. has 43 pumped storage facilities
that hold about 22 gigawatts. Yet, just one small operation has been
added since 1995 — and it is unknown how many of more than 90 planned
facilities can overcome economic, legal and practical issues that
force long delays.
Three projects have received permission
from the Federal Energy Regulatory Commission (FERC), but none are
being built.
In contrast, more than 60 are being built
worldwide, mostly in Europe, India, China and Japan.
Malcolm Woolf, president of the National
Hydropower Association, complained during a January hearing of the
Senate Energy and Natural Resources Committee. He said official
approval involves too many agencies.
“The … process is crazy,” he said.
Criticisms of pumped storage
Environmentalists are worried about
pumped storage because reservoirs typically are formed by hydropower
dams. Such dams can block fish movements, damage water quality and
release methane, a greenhouse gas. Also, most plants continuously draw
water from rivers.
But recent designs include “closed-loop”
systems that use a surface or underground supply, then repeatedly
cycle that water between reservoirs. Water would be added only to make
up for evaporation or leaks.
The Hydropower Reform Coalition,
representing environmental groups, says it might support such projects
under “very limited circumstances.”
Yet some are drawing resistance,
including the Goldendale Energy Storage Project in Washington state.
It would send water between two 24.3-hectare reservoirs on opposite
sides of a hill.
The facility could power nearly 500,000
homes for up to 12 hours, according to Rye Development, which is
leading the project. It is seeking FERC approval and is scheduled to
go online in 2028 but still needs permission from Washington state.
Environmental groups fear harm to
wetlands and wildlife, while Native American tribes say the project
would cross onto a sacred area.
“What are we willing to sacrifice to get
this technology online?” said Bridget Moran, an associate director of
American Rivers.
Developers say the project would include
cleanup of the polluted, lower reservoir area.
Future
As the market for stored energy grows,
new technologies are appearing.
Texas-based Quidnet Energy, for example,
has developed a pumped storage system that forces water underground,
holds it amid rock layers and releases it to power turbines.
For now, batteries are the leading
competitor to pumped storage plants, which can generate power for
eight to 16 hours. Lithium-ion batteries usually last up to four
hours, but longer-lasting ones are in the works.
“Are we going to get to the point where
an eight-hour battery is cheaper than a pumped storage plant? That’s
the billion-dollar question,” said Paul Denholm, an expert with the
National Renewable Energy Laboratory.
A 2016 Energy Department report said the
U.S. network could have 36 gigawatts of new pumped storage capacity.
“We don’t think pumped storage is the
be-all, end-all but it’s a vital part of our storage
future,” said Cameron Schilling, vice president of markets for the
hydropower association. “You can’t decarbonize the
system without it.”
I’m John Russell.
John Flesher reported on this story
for the Associated Press. John Russell adapted it for VOA Learning
English.
____________________________________________________________________
Words
in This Story
hydropower – n.
of or relating to production of electricity by waterpower
reservoir – n.
an artificial lake where water is collected and kept for use
evaporation –
n. a change in state from a liquid to a vapor
vital – adj.
very important
decarbonize – v.
to remove carbon from
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