A pact designed to keep the lights on across South America could instead spread a shortage across borders, according to a paper published on Thursday. Its authors say the draft rules for Brazil, Argentina, Paraguay and Uruguay may push governments to export power just as low reservoirs leave them struggling to meet demand at home.
The paper models a severe dry spell hitting the four countries at once and warns that 12 million electricity connections could enter a critical reserve zone if emergency exports are triggered without a clear limit. It does not predict certain blackouts, but says the proposed accord has no agreed method for rationing power when every member is short.
When help becomes a hazard
The Southern Current Accord is due to be signed at a 17 October summit in Montevideo. Its aim is to speed emergency electricity trades and coordinate reserves among the four countries, which already exchange power through cross-border links. Bolivia and Chile have asked to join a wider coordination arrangement, prompting negotiators to discuss expansion before the original rules are settled.
The authors examined hourly rainfall and generation records from 1990 to 2025, then tested how the draft’s “available surplus” language might work during drought. In the model, a shared dry spell cuts hydropower output across the region by 23%. A 12% reserve threshold then activates export requests in more than one country at once, even as each grid operator tries to protect local supply.
“The pact treats surplus as if it were a stable number. In a drought, it can disappear between the morning forecast and the evening peak,” said Raisa Adriansyah, the paper’s lead author and a power-systems modeller at the South Current Research Institute in Curitiba. She said the accord could still prevent isolated failures, but only if members agree in advance on who gets scarce power and when exports stop.
In a drought, the pact could turn four national emergencies into one shared emergency.
Raisa Adriansyah, power-systems modeller
The analysis is a stress test, not a forecast of the next dry season. But Efe Menemencioğlu, a grid analyst who reviewed the paper for the institute, said the authors had identified a “dangerous gap” in the draft: it sets out how members should offer electricity without defining a common emergency cutoff. “No operator wants to be the first to close the tap,” he said.
A rulebook under pressure
Brazil’s negotiators face a political trade-off. A binding export ceiling could reassure voters that domestic supplies come first, but might leave a smaller neighbour without help during a local breakdown. An open-ended promise, meanwhile, could expose Brazilian consumers to decisions made under pressure at a regional control desk.
Orrin Shanahan, an adviser to Brazil’s energy ministry, said the paper would be discussed by technical teams before the summit. “We are not signing a blank cheque,” he said, adding that any agreement must include measurable reserve triggers, public reporting and a way to pause exports during simultaneous shortages. Delegations from Argentina, Paraguay and Uruguay have not yet announced their positions.
The stakes reach beyond one treaty. Hydropower remains central to electricity supply in the region, and rainfall shifts can strain generation across national boundaries at the same time. If the pact grows to include more countries, its members will need to settle whether it is a promise to share spare power or a framework for sharing scarcity. The paper argues that the difference must be written down before the next dry season tests it.
