613 A key sensitivity variable is the electricity grid assumption, which affects both the RACER process and upstream concentrate production. Three scenarios were evaluated (Table 3): Table 3 – Climate change impact for various power purchase agreements. Electricity Scenario Climate Change Impact Arizona Renewable Grid (base case) 4.68 kg CO₂ eq. WECC Average Grid 6.24 kg CO₂ eq. WECC Renewable Mix (PPA) 4.67 kg CO₂ eq. The result is highly sensitive to electricity sourcing. The Arizona Renewable Grid scenario—in which 100% of electricity across the mining, RACER, and SX/EW stages is matched by renewable suppliers—is the primary basis for this analysis, reflecting Still Bright’s operational approach and unique ability to utilize renewable electricity as an input compared to other copper processing methods. The climate change of impact of RACER is further analyzed as a function of process stage, as well as input to the process. Table 4 – Climate change impact by stage. Stage Share kg CO₂ eq. per kg Cu Cathode Copper Concentrate (upstream) 80% 3.77 RACER Process 16% 0.74 SX/EW 4% 0.18 The dominant finding is that 80% of the total climate change impact originates upstream of Still Bright—in the mining and flotation of copper concentrate. Within that upstream burden, electricity consumption in mining and beneficiation is the largest driver. RACER’s own direct process footprint is small. The electrochemical reduction step accounts for only a fraction of total impact, and Still Bright’s commitment to utilizing renewable electricity renders SX/EW’s electricity contribution negligible. This pattern reveals the leverage available when applying RACER to lower-intensity upstream feedstocks, as explored in Section II.
RkJQdWJsaXNoZXIy MTM0Mzk2