A dry reservoir is a local problem until the country depending on it has nowhere else to buy electricity. A transmission line to a neighbor can change that. But only if the neighbor will still sell power when conditions become difficult.
That tension sits at the center of a peer-reviewed study published on September 17 in Nature Communications. Luis Ramírez and colleagues model electricity systems across 21 Latin American countries. Their striking result is not a new generator: coordinating existing kinds of generation, storage and cross-border connections could save up to roughly $32 billion a year by 2045 in the scenarios studied.
Those are modeled system savings, not money already saved or a promise about household bills. The useful insight is that trust has an engineering consequence. It changes what infrastructure countries build.
Different weather can become a shared resource
Electricity systems must continually match supply with demand. Solar output follows daylight; wind varies; reservoirs can store water for later generation, but cannot produce water that never arrives. Connecting places with different resources lets one system help another instead of requiring each to cover every shortfall alone.
The International Energy Agency’s 2021 hydropower assessment explains why this matters particularly in Latin America. Its climate projections did not show one uniform regional outcome: some subregions faced persistent declines, while others had different rainfall and runoff prospects. Geographic diversity is potentially valuable precisely because the weather does not fail everywhere in the same way.
Imagine two towns sharing backup equipment instead of each buying enough for its worst day. They can spend less together. Electricity networks work similarly, provided the connection can carry enough power and help is available when needed. The difficult part is deciding who pays for that shared capacity and what happens when both sides need it.
The new study tests that proposition with an optimization model: a calculation that searches for the least-cost combination of investments and operation under specified constraints. It compares fuller regional cooperation with systems largely limited to today’s interconnections, and examines intermediate cooperation among regional blocs. It varies water availability in the Andean and Southern Cone regions.
A large saving is not the same as an easy bargain
The supplementary cost table makes the comparison concrete. With low hydropower availability in both regions, modeled annual system costs in 2045 are $162.0 billion without further integration and $130.1 billion with it: a difference of $31.9 billion. Investment in generation, storage and transmission is included; the result is not simply cheaper fuel.
Sharing changes where it makes sense to build. A country may need less domestic backup if reliable imports can cover a shortage. Another may build more generation to serve its neighbors. The region can become cheaper to supply overall even though individual countries take on different dependencies.
The authors therefore examine both the cost of refusing cooperation and the exposure created by trusting a shared system that might underperform. Their analysis identifies Bolivia and Uruguay as particularly exposed in the latter comparison. That is an argument for designing guarantees, not evidence that either country should accept whatever deal produces the lowest regional total.
There is also a narrower sovereignty comparison: requiring countries to preserve more self-sufficiency raises modeled costs even when transmission investment is allowed. It is a different calculation from the $31.9 billion integration comparison. Treating every headline number as the same “cost of mistrust” would blur the choices the study is trying to separate.
The agreement is part of the power system
This remains scenario analysis. Each country is represented as a single network node, so the model cannot settle every internal bottleneck or local siting dispute. Full cooperation is an idealized condition. Future demand, technology costs and hydrology are assumptions, not observations from 2045. A related preprint appeared in 2025; this week’s journal publication is a new occasion to examine the work, not the first appearance of the idea.
The authors’ political argument—that climate stress creates an opportunity for deeper integration—is an interpretation alongside the modeling. The computation does not prove that governments will agree, or that savings will reach consumers fairly. The study also discloses support from Chile’s transmission-industry association.
For readers, the practical distinction is between a line on a map and a dependable shared service. A credible project needs rules for funding, emergency supply, compensation and distributing gains. The next meaningful advance would be an interconnection agreement that specifies those obligations and finances the infrastructure to honor them. That is when a modeled regional advantage begins to become something people can rely on.
Keep exploring
- Why finishing a solar farm is not the same as delivering its power — the practical role of grid commissioning.
- Google’s geothermal deal puts the power plant first — another approach to dependable low-carbon supply.
- Who pays for new grid capacity? — the distribution question behind infrastructure expansion.
AI-assisted. Sources checked.
