Life-Cycle Energy and Greenhouse Gas Emission Benefits of Lightweighting in Automobiles: Review and Harmonization

Abstract

Replacing conventional materials (steel and iron) with lighter alternatives (e.g., aluminum, magnesium, and composites) decreases energy consumption and greenhouse gas (GHG) emissions during vehicle use but may increase energy consumption and GHG emissions during vehicle production. There have been many life cycle assessment (LCA) studies on the benefits of vehicle lightweighting, but the wide variety of assumptions used makes it difficult to compare results from the studies. To clarify the benefits of vehicle lightweighting we have reviewed the available literature (43 studies). The GHG emissions and primary energy results from 33 studies that passed a screening process were harmonized using a common set of assumptions (lifetime distance traveled, fuel-mass coefficient, secondary weight reduction factor, fuel consumption allocation, recycling rate, and energy intensity of materials). After harmonization, all studies indicate that using aluminum, glass-fiber reinforced plastic, and high strength steel to replace conventional steel decreases the vehicle life cycle energy use and GHG emissions. Given the flexibility in options implied by the variety of materials available and consensus that these materials have substantial energy and emissions benefits, it seems likely that lightweighting will be used increasingly to improve fuel economy and reduce life cycle GHG emissions from vehicles.

Driving Behaviour and Sustainable Mobility—Policies and Approaches Revisited

“…The light-weighting policy unanimously has fewer trade-offs in adoption of novel and new materials and technologies [160,165]. Lightweight vehicles use aluminium, magnesium alloy, carbon-fibre reinforced polymer (CFRP) and other materials, which have lower GHG and CO 2 emissions over vesicle's life-cycle than iron and steel [165][166][167]. For example, replacing steel Mg has led to 5.7% weight reduction that decreases the vehicle fuel consumption and life cycle emissions by 1.3% and 0.8%, respectively.…”

Sustainable Supply Chain Management: The Influence of Disposal Scenarios on the Environmental Impact of a 2400 L Waste Container

“…[30]. This is the reason why LCA is being more often used during the early stages of a product's life cycle [31][32][33]. LCA focuses on the environmental pillar of sustainability [34].…”

Lightweight Design Solutions in the Automotive Field: Environmental Modelling Based on Fuel Reduction Value Applied to Diesel Turbocharged Vehicles

“…"Light-weighting" is unanimously recognized as one of the key measures in order to lower car use stage FC and environmental burden [19][20][21][22][23]; on the other hand, the adoption of novel materials and innovative technologies often shifts the impacts to other LC stages (e.g., production and End-of-Life (EoL)) [24,25]. In this regard, plastics, composites, aluminium, high-strength steel and magnesium and sandwich materials are expected to play a leading role in the future.…”