Justice at Itaipu

The story behind the numbers

Itaipu has generated more electricity than any other hydropower plant in history. According to Guinness World Records, it is also the most expensive single object on Earth.

A binational dam, owned in equal parts by Paraguay and Brazil, Itaipu is one of Paraguay’s greatest assets: its main source of electricity and a major foreign-exchange earner for the national treasury.

For the past decade, DEMOS has studied its accounts. More than half a century after the signing of the 1973 Treaty, we seek to answer questions that remain unanswered: how much the dam really cost, why it cost so much, who bore that cost, and how much Paraguay would have received if the energy it ceded to Brazil had been sold at market prices.

Through this research, DEMOS seeks to improve public debate on Itaipu. We contribute new data developed through rigorous research and a measured assessment of an issue at the heart of the relationship between Paraguay and Brazil.

We undertake this work without hostility, guided by a firm commitment to transparency, justice, and mutual respect for each nation’s sovereignty. These principles are the foundation of a stronger relationship and closer ties between the people of these two neighboring countries.

How much Itaipu really cost

The binational entity reports several figures for the dam’s cost. They measure different concepts and yield different totals. Using its own balance sheets, we reconstructed the amounts actually paid, year by year.

Why it cost so much

In addition to construction costs, the study examines the cost of borrowing: the debt, interest rates, and financial terms that made financing more expensive over half a century.

Decisions, not just context

The oil shocks, the debt crisis, and Brazilian inflation shaped this period. But the study highlights the impact of specific decisions—made or not made by identifiable institutions at particular moments.

Who paid

We trace how the cost of the debt was passed on through Itaipu’s electricity tariff to the bills paid by households and businesses on both sides of the Paraná River.

Paraguay’s ceded energy

Paraguay cedes most of its share of Itaipu’s electricity to Brazil. The study compares what it received in return with the value of that energy in the Brazilian market.

What Itaipu does not publish

Itaipu does not publish all the information needed for an audit. Several data series had to be reconstructed from official sources. This lack of information is itself a finding.

Why the study matters now

Paraguay and Brazil are reviewing Annex C of the Treaty, which establishes Itaipu’s financial framework. The study provides evidence to inform that discussion.

How we work

We describe this work as a financial archaeology of Itaipu. Using scattered and incomplete records, we have reconstructed half a century of accounts and analyze them in light of the historical context and the power relations at play.

The study draws on official sources: Itaipu’s balance sheets, annual reports, and contracts, and statistics from public institutions in Brazil and Paraguay. Using these sources, we have built dozens of databases. Every reconstructed series is identified as such, and all monetary values are expressed in constant 2024 U.S. dollars. It is an honest reading of the numbers: we report what the data show.

To assess the impact of excess construction costs and financing costs, we use counterfactual scenarios: what would have happened to the debt, the electricity tariff, and electricity bills if certain decisions had not been made. These methods are used in forensic accounting.

The study is now undergoing final verification and peer review.

We presented preliminary findings in Asunción in 2018 and 2019, in Ciudad del Este and to electricity-sector unions in 2019, and before Paraguay’s National Congress in 2022 and 2023. In August 2026, President Santiago Peña received an update on the study at Mburuvichá Roga, the presidential residence. Members of his cabinet also attended, as did the president of ANDE, Paraguay’s state electricity company and co-owner of Itaipu.