Despite the attraction of battery power two stubborn obstacles remain. End-of-life recycling is troublesome and not currently cost effective, meaning alternatives such as so-called ‘second life’ use are being touted.
Also acquiring the materials for manufacture in the first place has a significant carbon cost. However, details of a project to examine the benefits of extracting the materials from the sea have been published and it makes for interesting reading. The project leader is Daina Paulikas from the University of Delaware's Centre for Minerals, Materials and Society. Paulikas explained, “We wanted to assess how metal production using either land ores or polymetallic nodules can contribute to climate change. Looking from mining to processing and refining, we quantified three indicators for each ore type: direct and indirect carbon-dioxide-equivalent emissions, disturbance of existing sequestered-carbon stores, and disruption of future carbon-sequestration services. These three indicators directly impact the remaining global carbon budget to stay below 1.5 degrees C warming.”
Polymetallic nodules from the Clarion Clipperton Zone in the Pacific Ocean contain rich concentrations of the four metals required for EVs in a single ore, including nickel, a crucial ingredient in EV batteries, which will increasingly be mined from beneath large forested carbon sinks in tropical areas like Indonesia and the Philippines. It studied the demand scenario for producing nickel and cobalt, manganese and copper to supply one billion 75KWh EV batteries with a cathode chemistry of NMC 811 (80% nickel, 10% manganese, 10% cobalt). It then compares the climate change impacts of supplying these four metals from two sources: conventional ores found on land and polymetallic rocks found unattached on the seafloor at 4-6 km depth.
Paulikas continued, “Terrestrial miners are handicapped by challenges like falling ore grades, as lower concentrations of metal lead to greater requirements of energy, materials and land area to produce the same amount of metal. Furthermore, the actual collection of nodules entails a relatively low energy, land, and waste footprint compared to a conventional mine. When it comes to emissions, even when we assume a complete phase-out of coal use from background electric grids for process inputs, our model shows that metal production from high-grade polymetallic nodules can still produce a 70% advantage. The study found that producing battery metals from nodules can reduce active human emissions of CO2e by 70-75%, stored carbon at risk by 94% and disruption of carbon sequestration services by 88%.”
• Read more about deep sea mining here.