7 Modern Wonders
of the World
Itaipu is a hydroelectric
dam on the Paraná River located
on the border between Brazil and Paraguay.
The name "Itaipu"
was taken from an isle that existed
near the construction site. In the
Guarani language, Itaipu means "the
sound of a stone". The American
composer Philip Glass has also written
a symphonic cantata named Itaipu in
honour of the structure.
Itaipu Binacional is
a company that runs the largest operational
hydroelectric power plant in the world.
It is second only to the Three Gorges
Dam in generating capacity. It is
a binational undertaking run by Brazil
and Paraguay at the Paraná
River on the border section between
the two countries, 15 km north of
the Friendship Bridge. The project
ranges from Foz do Iguaçu,
in Brazil, and Ciudad del Este in
Paraguay, in the south to Guaíra
and Salto del Guaíra in the
north. The installed generation capacity
of the plant is 14 GW, with 20 generating
units of 700 MW each. In the year
2008, it achieved its generating record
of 94.68 billion kilowatt-hours (kWh),
which supplied 90% of the energy consumed
by Paraguay or 19% of that consumed
by Brazil
Negotiations
between Brazil and Paraguay
The concept behind Itaipu Power Plant
is the result of heavy negotiations
between the two countries during the
1960s. The "Ata do Iguaçu"
(Iguaçu Act) was signed on
July 22, 1966, by the Brazilian and
Paraguayan Ministers of Foreign Affairs,
Juracy Magalhães and Sapena
Pastor, respectively. This was a joint
declaration of the mutual interest
in studying the exploitation of the
hydric resources that the two countries
shared in the section of the Paraná
River starting from and including
the Salto de Sete Quedas to the Iguaçu
River's watershed. The Treaty that
gave origin to the power plant was
signed in 1973.
Construction starts
In 1970, the consortium formed by
the companies IECO (from the United
States of America) and ELC Electroconsult
S.p.A. (from Italy) won the international
competition for the realization of
the viability studies and for the
elaboration of the construction project.
Work began in February 1971. On April
26, 1973, Brazil and Paraguay signed
the Itaipu Treaty, the legal instrument
for the hydroelectric exploitation
of the Paraná River by the
two countries. On May 17, 1974, the
Itaipu Binacional entity was created
to administer the plant's construction.
The works began in January of the
following year.
Paraná River rerouted
On October 14, 1978, the Paraná
River had its route changed, which
allowed a section of the riverbed
to dry so the dam could be built there.
Agreement by Brazil, Paraguay
and Argentina
An important diplomatic settlement
was reached with the signing of the
Acordo Tripartite by Brazil, Paraguay
and Argentina, on October 19, 1979.
This agreement established the allowed
river levels and how much they could
change as a result of the various
hydroelectrical undertakings in the
watershed that was shared by the three
countries. At that time, the three
countries were ruled by military dictatorships.
Argentina was concerned that, in the
event of a conflict, Brazil could
open the floodgates, raising the water
level in de la Plata River and consequently
flood the capital city of Buenos Aires.
Formation of the lake
The plant's reservoir began its formation
on October 13, 1982, when the dam
works were completed and the side
canal's gates were closed. Throughout
this period, water rose 100 meters
(330 ft) and reached the gates of
the spillway at 10:00 AM on October
27 due to the heavy rains and flooding
that took place at the time.
On May 5, 1984, the
first generation unit started running
in Itaipu. The first 18 units were
installed at the rate of two to three
a year; the last two of these started
running in the year 1991.
The last two of the
20 units started operations in September
2006 and in March 2007, thus raising
the installed capacity to 14,000 MW
and completing the power plant. This
increase in capacity will allow for
18 generation units to remain running
all of the time while two stay down
for maintenance. Due to a clause in
the treaty signed between Brazil,
Paraguay and Argentina, the maximum
number of generating units allowed
to operate simultaneously can not
exceed 18 (see the agreement section
for more information).
The rated nominal power
of each generating unit (turbine and
generator) is 700 MW. However, because
the head (difference between reservoir
level and the river level at the foot
of the dam) that actually occurs is
higher than the design head, the power
available exceeds 750 MW half of the
time.
Each turbine generates
around 700 megawatts; for comparison,
all the water from the Iguaçu
Falls would have capacity to feed
only two generators.
Power transmission
Of the currently 18 generator units
installed, 9 of them generate in 50
Hz, the grid frequency of Paraguay
and 9 generate in 60 Hz, the Brazilian
grid frequency. There's also a power
converter on the Brazilian side that
allows the transformation of 50 Hz
into 60 Hz energy that is not used
in Paraguay.
"Wonder of the Modern
World"
In 1994, the American Society of Civil
Engineers elected the Itaipu Dam as
one of the Seven Wonders of the Modern
World. In 1995, the American magazine
Popular Mechanics published the results.
