Cradle-to-gate greenhouse gas (GHG) burdens for aluminum and steel production and cradle-to-grave GHG benefits of vehicle lightweighting in China
Greenhouse gas (GHG) burdens of steel and aluminum production and life cycle benefits of vehicle lightweighting in China were evaluated. Production of advanced high-strength steel (AHSS) and wrought aluminum (Al) have average cradle-to-gate GHG emissions of 3.9 and 17.5 kg CO2eq/kg. Lightweighting benefits for eleven passenger car models over five driving cycles (including real-world and regulatory cycles) were determined. Lightweighting using AHSS to replace conventional steel has cradle-to-grave GHG savings in all cases, mainly attributed to savings in material use. Wrought Al has a much higher GHG production burden than AHSS and requires greater fuel savings in the use phase to achieve net cradle-to-grave GHG savings. Maximum GHG savings occur with Al versus AHSS in cases where the powertrain is resized, travel is congested, or lifetime travel distance is long. A typical Beijing peak-hour driving cycle with low speed and frequent stop-and-go has higher fuel reduction values (FRVs) and GHG savings than other cycles. Congested travel conditions make lightweighting a particularly effective emissions reduction strategy in China.