This chapter analyses the energy-intensive process of carbon fibre manufacturing and how process parameters affect fibre properties, emissions, and energy use. These relationships are assessed by examining fibre properties, emitted gases, and energy consumption under varying processing conditions on a continuous production line. The work shows that carbon fibre production time can be reduced by up to 33% while maintaining mechanical properties, leading to up to 30% less energy use and a cleaner process. However, this efficiency gain is limited to specific time and temperature ranges, beyond which yield and material properties decline. The findings are subsequently scaled to commercial quantities, highlighting potential improvements in energy efficiency, environmental impact, and cost through process optimization.