Nickel can have complex supply chains. Refined nickel production can be split into Class I (nominally pure nickel metal) and Class II products, with several intermediates used in different process routes. Intermediates and Class I and II products can be converted to nickel sulfate hexahydrate, the battery industry product of choice.

LCAs can quantify the environmental impacts of a production process or manufacturing a product and account for direct impacts such as greenhouse gas emissions from the process and embodied impacts of the necessary energy, chemicals, raw materials and transportation. This latter aspect is more important for production routes with higher reagents and energy mineral use. It is important to note that LCA covers a broad range of environmental impact categories that should be considered.

The study's results indicate a wide range of climate change impacts per kilogram of nickel in nickel sulfate hexahydrate. Sulfide resources allow for the lowest climate change impact nickel products, and laterite resources generally have a higher climate change impact.

This study has shown that for each major process technology for producing battery-grade nickel products to battery-grade nickel products, it is not appropriate to assume an average climate change impact. Understanding process technology, resource characteristics, and energy sources associated with a unique nickel supply chain is critical to understanding the exact climate change impact of that supply chain.