^^ Mining, refining, ore processing
^^ Drilling, distillation, processing
^^ Cement manufacturing
^^ Asphalt pavement
^^ Pavement base manufacturing
^^ Concrete pavement manufacturing
^^ Melting, casting
Casting, forming, machining
(H Paint manufacturing
(13 Bridge manufacturing
(14 Stamping, shaping, joining
Infrastructure component manufacturing
(16 Release for service
([7 Bridge and component manufacturing
(¿9 Asphalt shredding
(20 Concrete crushing
1 Bridge disassembly and demolition
22 Infrastructure disassembly and recycling
¡23 Magnetic separation
Figure 34.3 The life cycle of the automotive infrastructure, and the processes that occur during that cycle inventory (LCI) component of LCA has been applied to cars and car families with some success (Sullivan et al. 1998; Finkbeiner et al. 2000). However, a variety of uncertainties and assumptions render the results somewhat problematic (Keoleian et al. 1998; Lave et al. 1998; Saur et al. 1998). To improve the efficiency and communicability of LCAs, streamlined LCAs (SLCAs) have been developed over the past several years (for example, Graedel 1998) and can readily be applied to cars. In the approach we will use here, the SLCA assessment system has as its central feature a 5 X 5 assessment matrix, one dimension of which is life cycle stages and the other of which is environmental stressors. (In the present case, the life stages are defined as pre-manufacture, manufacture, product delivery, product use and end of life. The environmental stressors chosen are materials choice, energy use, solid residue generation, liquid residue generation and gaseous residue generation.) To use the SLCA matrix tool, the assessor studies the product design, manufacture, packaging, in-use environment and likely disposal scenario and assigns to each element of the matrix an integer rating from 0 (highest impact, a very negative evaluation) to 4 (lowest impact, an exemplary evaluation). In essence, what the assessor is doing is providing a figure of merit to approximate the result of the more formal LCA inventory analysis and impact analysis stages. She or he is guided in this task by experience, a design and manufacturing survey, appropriate checklists and other information.
As an additional aid to analysis and interpretation, 'target plots' can be constructed. In these displays, the value of each element of the matrix is plotted at a specific angle. (For a 25-element matrix, the angle spacing is 360/25= 14.4°.) A good product or process shows up as a series of dots bunched toward the center, as would occur on a rifle target in which each shot was aimed accurately. The plot makes it easy to single out points far removed from the center and to mark their topics out for special attention by the design team. Furthermore, target plots for alternative or evolutionary designs of the same product permit quick comparisons of environmental attributes.
Model T Fords were produced in the 1920s at the River Rouge Plant south of Detroit. Henry Ford's policy was to centralize manufacture and to control the supply of materials needed. As a result, the Ford Company owned iron mines, forests, a railroad, a glass plant and Great Lakes shipping companies. The Rouge Plant to which this material flowed was the largest manufacturing facility in the world. It provided substantial opportunities for environmental degradation, but Henry Ford's obsession with avoiding waste (Jensen 2000) resulted in a number of recycling activities that we would today call forward-looking: recovery of coke oven gases and use of wood scraps for fuel, for example. The vehicles themselves were evolutions of horse-drawn carriage design, and utilized relatively simple materials and processes.
By the 1950s, manufacturing activities were decentralized, massive vehicles with little recycling potential were common, and Henry Ford's legacy of waste minimization had largely been forgotten. Emissions to air, water and soil were substantial, and recycling activities were generally absent.
The 1980s saw major changes. Design attention was focused on the manufacturing and product use life stages, and environmental regulations and the oil crisis encouraged much-improved emissions performance and on-road fuel efficiency.
By 1998, the ubiquitous presence of automotive electronics had further improved the efficiency and reliability of vehicles, and pollution prevention programs in manufacturing were reducing environmental impacts at that life stage as well. Many plastic parts were being made of salvaged material. Much effort was being made to design vehicles with recycling in mind.
During this 80-year period, the materials from which cars were made evolved substantially. As with the carriages and wagons that provided much of the inspiration for early designs, the 1920s car frame was largely of iron, the engine and control linkages of steel, and the body of wood. By weight, early vehicles were about three-fourths iron and steel, with wood, seats, tires and fluids making up most of the remainder. By the 1950s, wood was no longer in use, and the amount of iron and steel contained in the car had doubled. Materials used in the mid-1980s were very different: iron and steel content per vehicle was almost back to the 1920s level as cars became smaller. Some of that loss was compensated for by aluminum and plastic, however, both of which were in the 90kg per vehicle range. The late 1990s vehicles were heavier than those of a decade earlier; much of this increase comes from enhanced control, safety and convenience features, though increasing vehicle size was a factor as well.
Making use of the information described above, streamlined life cycle assessments have been conducted on the Ford sedans from four eras. In this section the summary information derived from the comprehensive assessments will be presented and commented upon. Figure 34.4 shows the results for each of the four vehicles, presented individually for each of the five life stages and then collectively over the entire lives of the vehicles.
Recall that the maximum score for each matrix element is four and, since each life stage has five different environmental concerns, the maximum score for each life stage is 20. The top panel in Figure 34.4 evaluates life stage 1, pre-manufacture. Here the 1920s and 1998 vehicles are essentially equivalent at about 10 out of 20, while the 1950s vehicle scores about half as well and the 1980s vehicle only slightly better. In general, the higher scores for the 1920s vehicle reflect the use primarily of benign materials and of highly integrated manufacturing. Those for the 1998 vehicle reflect intensive use of recycled and energy-efficient materials, and of close supervision of the environmental attributes of supplier components.
The manufacturing life stage is shown in the second panel of Figure 34.4. The 1998 vehicle clearly scores better than the others, and is more than three times better than the 1950s vehicle. As with life stage 1, the 1920s vehicle ranks second, the 1980s vehicle third. Manufacturing in the 1920s involved little in the way of chemicals, and re-use of scrap materials was extensively practiced. A steady increase in scoring (from a low start) occurred after the 1950s. Among the reasons are the introduction of CFC solvents in the 1940s (and their eventual elimination by the 1990s), the increasing control of volatile organic carbon compounds (VOCs) from painting operations, and the increasing amounts of recycling that occurred toward the end of the 20th century.
The third panel - the packaging and shipping life stage - continues to show the 1998 vehicle as environmentally superior. The rest are bunched more closely than before, with the 1920s and 1980s vehicles essentially equal. The scoring essentially reflects the short time and small environmental impacts that occur during the product delivery stage, and the fact that approaches to delivering vehicles have changed less over time than have approaches to other life stages.
The product use stage reflects principally the degree of exhaust emissions control implemented on the vehicles. As a result, the 1998 vehicle has the highest score, the 1980s vehicle the next highest. The 1920s vehicle scores higher than the 1950s vehicle, not because of
Score for stage 1
Was this article helpful?