Energy Security in Isolated Systems: The Case of Brazil's Legal Amazon

Most of Brazil’s electricity flows through one of the largest interconnected power grids in the world, the Sistema Interligado Nacional (SIN). A large share of the country’s territory, however, is not connected to it. In the Legal Amazon, many towns and communities are served by isolated systems: local power plants and networks that are not linked to the national grid.

What an isolated system is

An isolated system is a self-contained electricity supply for a locality or group of localities. Distance, dense forest and river geography make transmission lines expensive or impractical, so electricity is generated close to where it is used.

According to the federal government’s latest planning cycle for isolated systems (2026–2030), around 160 localities, home to roughly 1.97 million people, are still served this way, down from 212 isolated systems in 2022. The largest change came in September 2025, when Boa Vista, the capital of Roraima, was connected to the national grid, roughly halving the load of the isolated systems. Sixteen more localities are planned to be connected by 2030.

Historically, that generation has relied heavily on diesel engines. Fuel often travels long distances by river or road before it reaches the power plant, which makes supply vulnerable to droughts, floods and logistics disruptions.

Why it matters

Isolated systems raise three connected issues:

• Cost. Generating electricity from transported diesel is expensive. In Brazil, part of that cost is shared by all electricity consumers through a sector fund, the Conta de Consumo de Combustíveis (CCC), so the issue has national, not only regional, relevance.
• Reliability. Outages and capacity limits constrain public services, such as health care, schools and water supply, and the productive activities that could generate income locally.
• Emissions. Diesel generation emits greenhouse gases and local air pollutants.

For a remote municipality, energy is rarely just an energy question. It shapes whether a fish-processing plant can keep a cold chain, whether a clinic can store vaccines, or whether a small industry can expand.

The options being studied

There is no single solution. Planners and operators in Brazil have been examining combinations of:

1. Hybrid systems. Solar generation combined with batteries and existing diesel units can reduce fuel use while keeping supply stable.
2. Local renewable sources. Depending on the location, these may include biomass from agricultural and forestry residues or small hydropower.
3. Grid connection. Where demand and distance justify it, connecting a system to the national grid can replace local generation altogether.
4. Programs for remote communities. Federal programs such as Mais Luz para a Amazônia have focused on bringing electricity from renewable sources to remote communities that had no access.
5. Emerging technologies. Small modular reactors and microreactors are discussed internationally as a possible long-term option for remote, high-demand sites. They remain at an early stage, and any role in the Amazon would require extensive technical, regulatory and social assessment.

Questions that decide the outcome

Choosing between these options depends less on technology than on a few practical questions: How much demand is there today, and how much will productive activity add? Who will own and operate the assets? How will costs be shared between local consumers, the sector fund and public budgets? And who will maintain the equipment in places that are hard to reach?

These are institutional and financial questions as much as engineering ones. Answering them well requires coordination between federal planners, state and municipal governments, utilities, communities and, often, international partners with experience in similar settings.

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This article is part of World Funding’s work on energy security for remote and isolated regions. It describes the general context and does not refer to any specific project.

Sources and further reading

1. MME/EPE — Planejamento do Atendimento aos Sistemas Isolados, ciclo 2026–2030 (as reported by Cenário Energia, Jan 2026)
2. ONS — Sistemas Isolados (Brazilian National Electric System Operator)
3. EPE — Planejamento do atendimento aos Sistemas Isolados (Energy Research Office)
4. Ministry of Mines and Energy — Programa Mais Luz para a Amazônia

This article is for general information and education. It is not legal, financial, investment or engineering advice.