Can Solar and Hydrogen Replace Diesel in the Amazon’s Isolated Grids?

A new study finds that solar power combined with batteries or green hydrogen could cut emissions in Amazon’s diesel-dependent isolated grids by up to 92 percent, and in some cases even lower electricity costs. However, land availability is a critical constraint, making renewable transitions feasible in some towns but spatially limited in others.

In much of Brazil, electricity is already relatively clean. But deep in the Amazon, nearly 200 isolated power systems still depend heavily on diesel generators. Fuel must travel long distances by river or road to reach remote communities, making electricity expensive, unreliable and highly polluting. In some cases, more than a liter of diesel is effectively used just to deliver one liter to its destination.

Now, researchers from the National Institute for Space Research, the Federal University of São Paulo and the Federal University of Santa Catarina are asking a bold question: can the Amazon’s isolated towns run fully on renewable energy instead?

Their new study examines whether solar power, supported by batteries and green hydrogen, could replace diesel in two real communities in Amazonas state: Careiro da Várzea and Rio Preto da Eva.

Can Solar Power Do the Job?

The researchers built a detailed energy model using eleven years of hourly solar data, real electricity demand figures and up-to-date technology costs. They tested three scenarios: continuing with diesel, switching to solar plus batteries, and switching to solar plus hydrogen plus batteries.

The results show that solar energy can technically meet all electricity demand in both towns. But there is a catch. Renewable systems need much more installed capacity than diesel plants. Compared to optimized diesel systems, total installed capacity would need to increase more than six times in battery-based systems, and more than ten times in hydrogen-based systems.

Why so much more? Solar panels do not produce power at night and output drops on cloudy days. To ensure a reliable supply, systems must be oversized and combined with storage.

Batteries vs. Hydrogen

In Rio Preto da Eva, a town of about 35,000 people with available pastureland, the findings are encouraging. A solar-plus-battery system could cut greenhouse gas emissions by more than 90 percent and even reduce electricity costs by around 13 percent compared to diesel.

Adding hydrogen changes the picture. Hydrogen works as long-term storage: excess solar power splits water into hydrogen, which is stored and later converted back into electricity. This allows energy to be saved for longer periods, but it also adds costs and energy losses.

Under normal conditions, hydrogen systems were more expensive than battery-only systems. However, both options still reduced emissions dramatically compared to diesel.

When Land Becomes the Problem

The biggest surprise in the study is how important land availability is.

Solar farms need space. The researchers limited installations to pasture and already cleared areas within one kilometer of each town. In Careiro da Várzea, which is surrounded by rivers and floodplains, there simply is not enough suitable land to install the number of solar panels required. Large-scale ground-mounted solar systems are practically impossible under current conditions.

Rio Preto da Eva has more land, but even there, limits change the outcome. When solar expansion was restricted to the minimum required area, storage needs increased sharply. In the battery scenario, storage capacity had to expand dramatically, pushing electricity costs much higher. Hydrogen systems handled land limits slightly better because hydrogen can store large amounts of energy more cheaply over long periods compared to scaling up batteries.

In fact, under strict land constraints, the hydrogen system became slightly cheaper than the battery-only option. This does not mean hydrogen is always cheaper. It simply means different storage technologies respond differently when space is limited.

A Clean Energy Future, With Local Realities

The study shows that deep decarbonization in the Amazon is technically possible. Emissions can be reduced by up to 92 percent compared to diesel systems. In some towns, renewable systems could even lower electricity costs.

But geography matters. Some communities have enough land for solar farms, while others face natural barriers like rivers and wetlands. In places with limited space, alternatives such as rooftop solar, floating solar panels or hybrid systems may be needed.

The research makes one thing clear: switching from diesel to renewables in the Amazon is not just about sunlight or technology prices. It is about land, local conditions and smart planning. With the right mix of solutions, even remote rainforest towns could move toward cleaner, more secure and more affordable electricity.