By Beth Rush
Electric vehicles (EVs) are often positioned as an eco-friendly solution to cars that burn fossil fuels. However, their potential to reduce emissions depends on the performance of the lithium-ion batteries that power them. Many of those batteries rely on nickel-rich chemistries, which have created intense demand for high-grade ore, largely mined in Indonesia.
This overview walks you through how the mining process, processing parameters and tailings disposal methods contribute to widespread water contamination across Indonesia.
The Unseen Eco Costs When Nickel Is Crucial for EVs
You may not see the environmental cost when you look at an EV on the road, but the impacts of this demand become apparent far from manufacturing plants. Indonesia, where you’ll find the world’s biggest nickel reserves, has rapidly expanded its mining and refining operations to meet demand. This growth is threatening entire coastal ecosystems, with “dead zones” emerging in regions where mining waste enters rivers and marine environments.
Nickel plays a central role in the energy density of EV batteries. It is used in common cathode chemistries such as nickel-manganese-cobalt (NMC) and nickel-cobalt-aluminum (NCA). These chemical combinations enable EVs to travel longer distances between charges, helping manufacturers balance performance and affordability. High nickel content increases storage capacity, which is one reason EV companies continue to seek reliable supplies of battery-grade nickel.
Where you could easily calculate miles per gallon of fuel with a combustion engine car and budget appropriately for your road trip, an EV requires a larger charge capacity, and that’s where nickel comes in.
How is Nickel Used in EV Batteries?
Nickel helps stabilize the cathode structure and enables higher energy density. A battery with a nickel-rich cathode stores more energy without significantly increasing weight. That matters when designers are under pressure to create EVs that can travel further without relying on oversized, heavy battery packs. With more than half of all vehicles expected to be battery-powered by 2055, designing better, more efficient batteries sits at the center of the industry.
Building these batteries also requires materials beyond the cathode’s metals. EV battery packs contain engineered layers that include adhesives, insulation, separators and thermal management components. Design choices must balance performance, safety and life cycle requirements for future-forward efficiency. EV design considerations underscore the need for battery manufacturers to use consistent, high-quality materials at specific purity levels.
As EV production grows, the scale and intensity of upstream extraction magnify. When a country like Indonesia holds the largest mineral deposits but lacks sustainable mining parameters, the environmental cost can escalate quickly.
Indonesia — The World’s Nickel Epicenter
Indonesia has become the world’s largest producer of nickel. It accounts for a third of the world’s supply, which has led to extensive mining operations in rural areas, such as Sulawesi and Halmahera, where widespread deforestation now affects the region.
As mining accelerates, the landscape changes with it. New smelters, access roads and open-pit mines reshape coastlines and forests. These rapid changes increase sediment loads in nearby rivers, especially during flash floods and landslides triggered by erosion on exposed land.
Indonesia’s downstream strategy — keeping raw ore in the country to process it into semi-finished products — requires a large industrial footprint. More smelters, processing plants and infrastructure also mean increased energy use and emissions. Many facilities sit directly on the coastline to reduce transport costs, but this increases the risk of polluted runoff entering rivers or the sea when storms hit.
Seaside smelters produce runoff contaminated with heavy metals such as iron, chromium, nickel and arsenic. These metals can damage ocean ecologies and accumulate in marine food chains. Tailings are often pumped into enormous containment ponds, but just like your home pool, even well-built ponds can leak. When groundwater contamination flows into the ocean, fish and other marine life are affected.
The downstream study mentioned above shows that each ton of ore production generates about 1.6 tons of tailings. This volume of waste reduces the economic benefit of nickel extraction for local communities and challenges the environmental gains associated with EV adoption.
The Process From Red Earth to Toxic Seas
Nickel extraction involves several stages, and each one affects nearby water systems. The parameters that most directly contribute to “dead zones” — places where sediment, acidity and heavy metals eliminate marine life — are outlined here.
Pit Mining and Deforestation
Most of Indonesia’s ore comes from open-cast or surface pit mines. These operations require clearing large areas of forest, which leaves the soil unprotected. When heavy rainfall occurs, loose sediment washes into rivers and coastal zones.
Water samples from areas near mines and smelting stations in Sulawesi and Sorowako contain large quantities of contaminated sediment, including hazardous chromium VI and nickel. These substances harm living things, from microorganisms and fish to humans.
High sediment loads reduce water clarity, block sunlight and slow coral growth. You also see plumes of turbid water stretching several miles offshore near major mining corridors. This changes coral reefs and seagrass beds, which are essential habitats for fish nurseries that local communities depend on.
Pyrometallurgy Pollution
Pyrometallurgy is often used for higher-grade sulfide ore that cannot be refined through simpler methods. The process uses chemicals and high heat through steps like smelting, drying and refining.
Many Indonesian smelters run on coal-fired furnaces. These furnaces release carbon dioxide and other greenhouse gases, adding to global warming and the country’s local air-quality challenges. With 79 units already operating, 74 under construction and another 17 planned or permitted, these emissions influence both air and water systems.
Hydrometallurgy and Acid Leaching
Lower-grade limonite ore requires high-pressure acid leaching (HPAL). This process uses sulfuric acid at high temperatures and pressure levels to separate nickel and cobalt. The resulting slurry contains acidic liquids and fine mineral particles. If released into waterways, this mixture alters pH levels and increases suspended solids.
HPAL waste must be stored in engineered systems strong enough to hold up during Indonesia’s heavy tropical rains. However, researchers have reported problems. On Halmahera, several tailings storage sites have overtopped during storms, sending acidic waste into nearby rivers.
Tailing Disposal and Water Contamination
Tailings, the leftover waste from ore processing, directly threaten marine ecosystems. Two disposal methods are widely used, each associated with significant risks.
1. Deep-Sea Tailings Placement (DSTP)
DSTP sends contaminated slurry to the sea floor. In theory, it is meant to stay there. In practice, particles resuspend and drift. When they settle on coral habitats, they smother fish and reefs and reduce oxygen exchange. Heavy metals in the tailings add long-term toxicity to the marine environment.
Early studies of DSTP in Indonesia and Papua New Guinea show that it has not prevented ecological harm, and damage continues. Instead, it moves pollution deeper into the ocean, where natural recovery is slow.
2. Land-Based Containment Systems
Storage dams should prevent waste from entering the ocean, but they depend on strong construction and consistent maintenance. High rainfall increases the chance of overtopping or seepage. When dam walls crack or leak, metals such as nickel, iron and manganese flow downstream, spreading contamination through river systems and eventually into coastal waters.
Over time, waterways near containment failures turn brown or reddish, signaling high sediment and metal levels. Fish diversity drops, and entire aquatic food webs shift.
The Human Cost of “Green” Energy
When water quality drops, local communities feel it quickly. Near mining zones, fish numbers fall, reducing income for households that rely on coastal fishing. Market research shows a 2.5% decline in local fishing production, tied largely to shrinking fish populations.
Water contamination also affects daily life. Higher acidity or heavy metal concentrations interfere with drinking, bathing and crop irrigation. Many mining operations overlap with Indigenous land, leaving residents with fewer places to fish or grow food. Despite the wealth generated from ore, nearby communities often see little improvement in their quality of life.
A Complicated Path Forward
The demand for nickel will continue as the world shifts toward EVs. Energy-dense batteries rely on materials that often come from places with vulnerable ecosystems, including Indonesia. Reducing the environmental burden of this supply chain requires coordination between governments, manufacturers and researchers.
Some companies are exploring alternative battery types such as lithium iron phosphate, which does not require nickel. These chemistries can also draw materials from North America, reducing reliance on international mining. Mines are experimenting with improved HPAL processes that neutralize toxicity before disposal. Better monitoring programs can help identify contamination earlier.
Recycling is another long-term solution. Improvements in metal recovery could allow up to 95% of certain battery metals to be sourced from old batteries instead of new ore. As a consumer, you can purchase an EV that has a recycling-approved battery to reduce the demand for raw materials.
Improve Nickel Mining for Safer Ecologies
Safer mining practices depend on international frameworks for tailings management. Independent audits, transparency requirements and community oversight can bring stronger accountability. For Indonesia, investing in safe storage, recycling initiatives and upgraded processing technologies could prevent future ecological damage.
As EV adoption grows, industry leaders must balance performance requirements with environmental protection. Understanding where battery materials come from and how they affect local ecosystems is essential to building a more sustainable path forward. So ask vital questions before you drive from the showroom floor with your new EV.
Indonesia’s battery ore boom highlights the complex trade-offs in the shift to electric transportation. Nickel remains essential for many EV battery chemistries, and its role in increasing energy density continues to drive demand. At the same time, open-pit mining, HPAL processing and tailings disposal practices place significant pressure on watersheds in Sulawesi, Halmahera and other regions.
Sedimentation, acidified runoff and deep-sea tailings have contributed to documented declines in marine life and reduced water quality for nearby communities. Addressing these impacts requires coordinated efforts across the supply chain, including improved oversight, safer waste management systems, continued research into alternative chemistries and expanded recycling capacity.
Driving Toward a Cleaner Future
As the EV sector grows, balancing performance with environmental protection will remain a central challenge for manufacturers, policymakers and communities that depend on healthy coastal ecosystems. Ultimately, the demand comes from your purchases, so choose wisely and ensure Indonesia’s waterways “dead zones” don’t happen.