Domestic aluminium players would need a substantial increase in their renewable energy or low carbon-intensive power sources to meet their ambitious targets of 25 per cent reduction in carbon emissions in the next five-seven years and achieve net-zero status by 2050, ICRA said on Monday. "Domestic aluminium manufacturers have the highest carbon intensity of nearly 17-20t CO2e/tonne of aluminium, owing to the significant use of coal in generating captive power," ICRA said.