IN SUMMARY
Nickel is a cornerstone of the battery supply chain, and demand is rising as cathode chemistries shift toward higher nickel content. But “nickel” is not a single product with a single carbon number. The same battery-grade material, nickel sulfate hexahydrate, can be produced through several routes, each with its own resources, energy sources and chemistry. Minviro’s white paper measures this variability and explains why knowing the source and production route is essential to understanding a supply chain’s true climate change impact.
Carbon intensity varies widely. Across the modelled routes and transport scenarios, nickel entering the battery value chain ranges from roughly 5 to 105 kg CO₂e per kg nickel.
Route matters more than ore type alone. Laterite nickel via HPAL can carry a lower footprint than sulfide nickel via pyrometallurgy, depending on energy source and resource characteristics.
Averages hide the real picture. Up to a third of the total impact can be missed if only Scope 1 and Scope 2 emissions are counted, which is why full LCA is necessary rather than optional.
Two ore types, many routes to the same product
Refined nickel is generally split into Class I (nominally pure nickel metal) and Class II products, with a range of intermediates in between. All of these can be converted to nickel sulfate hexahydrate, the battery industry’s feedstock of choice, and the route taken depends first on geology. Sulfide ores carry nickel grades from 0.25% up to 4% and are usually concentrated by flotation, then treated pyrometallurgically through smelting and conversion to nickel matte. Laterite ores are surface deposits split into limonite and saprolite: saprolite is processed pyrometallurgically into ferronickel or nickel pig iron, while limonite is leached under high pressure and temperature with sulfuric acid (HPAL) to recover nickel and cobalt. In 2019, laterites supplied roughly 70% of global nickel and sulfides 30%, and the laterite share is expected to grow, led by new Indonesian capacity.
Measuring impact with life cycle assessment
Life cycle assessment (LCA) captures this complexity. It quantifies direct process emissions alongside the embodied impacts of energy, chemicals, raw materials and transport, and that embodied portion matters most for reagent- and energy-intensive routes, where ignoring it would understate the true footprint. For Nickel’s Carbon Challenge, our team modelled six production routes across three technologies, covering best and worst cases for each: sulfide via pyrometallurgy, laterite via HPAL, and laterite via RKEF. The system boundary is cradle to plant gate, with a functional unit of one kilogram of battery-grade nickel sulfate hexahydrate at 22% nickel. Background data came from Ecoinvent 3.9.1, using the Environmental Footprint 3.0 method.