When a customer purchases an item, it moves from the manufacturing category to the use category. For some products, the impact during the use phase may be small (such as for furniture). For others, however, the majority of their impact may occur during this phase (such as appliances and clothes).
But this still isn’t the whole story. When products are disposed of, they require more material and energy to collect, recycle, and dispose of. Some, in fact, have as big an impact in this phase as in any of the others. Nuclear waste and CRTs are notoriously difficult to dispose of appropriately, generating greater-than-aver- age materials and energy impacts in doing so (mostly due to their toxicity). Recycling materials is a good idea, but it also requires energy and materials for collection, sorting, reclaiming, cleaning, and transportation. These, too, must be factored into the equation.
Using recycled material or energy can often create a positive impact on LCA calculations, lowering overall material and energy impacts.
However, this only occurs for the recycled material or energy that is actually used in the manufacturing phase, not for the potential recycling that might occur because a product is designed to be recycled. In other words, just because that PET bottle can be recycled into other bottles or other products, doesn’t mean it will be. It could, just as easily, be dropped into the waste stream, end up in a landfill, or float endlessly in the ocean for years. The only recycled content that counts is that which gets recycled.
As daunting as an LCA seems to be, it is possible to conduct one, and there are two basic approaches.
… just because that PET bottle can be recycled into other bottles or other products, doesn’t mean it will be.
Process-based LCA, developed by the Society for Environmental Toxicology and Chemistry, the U. S. EPA, and the International Organization for Standardization (ISO) breaks down
the process for producing a product into its constituent activities, and evaluates the environmental impact of each individual step. The diagram in Figure 3.11 shows the hierarchy of process activities that must be identified in a process-based LCA. For each process in the diagram, materials and energy used, as well as emissions produced, must be identified, and the totals rolled up to create a full picture of
|
OVERALL PROCESS
SUB-SYSTEM SUB-SUB-SYSTEM FIGURE 3.11. http://www. flickr. com/photos/rosenfeldmedia/3259024392 Hierarchy of process activities in process-based LCA. |
the environmental impact of a product. These models require a considerable amount of work to develop, since they can require reaching far back into a product’s supply chain to collect relevant data. Because systems are interconnected, it’s not always clear where to consider a process’s boundaries, when to stop collecting data, and how to collect the data in similar formats so that all of the data can be used in the same assessment.
Economic Input-Output LCA (EIO-LCA) is an attempt to simplify this arduous process by focusing on the likely inputs and outputs that will have the most impact. Rather than measure actual materials and energy from the product or service’s life cycle (which is often unknown during development), designers and engineers use proxy data from common sources that average the impacts (see Figure 3.12). Developed by Wassily Leontief, who won the Nobel Prize in 1973, it represents a “general interdependency” model. This drastically simplifies the process, both in time and expense, but delivers estimates that are not as accurate.
 |
FIGURE 3.12. http://www. flickr. com/photos/rosenfeldmedia/3259008940 Averaging the financial impact of a product.
Nonetheless, it’s the only way to approach an LCA during the design and prototyping processes, when a finished, actual solution doesn’t yet exist. Data is available publicly at Web sites like www. eiolca. net
LCA is very much an engineering framework and can be cost – and time-prohibitive for smaller organizations and individuals to complete. In addition, the more complex the solution, the more difficult the assessment is, often in an exponential relationship to the number of parts and materials. In addition, the realities of manufacturing and distribution make the reporting difficult, if not impossible. For example, the same product produced in San Diego will have a drastically lower transportation impact when used locally than when distributed to San Francisco, Denver, and Portland, Maine. In order to accurately portray this impact in labeling and in order to make informed decisions (for both manufacturers and customers), each location of consumption would have to be calculated and displayed separately. For contemporary products created in multiple locations, shipped all over the world, with switching supply chains at the whim of last – minute market changes, this becomes nearly impossible.
Not only are LCAs time-consuming, but most manufacturers and service providers also don’t yet record or report the minute data needed to make these deep assessments possible. Current accounting methods for manufacturing, distribution, and maintenance operations just don’t require this data, and as such, most organizations don’t see the need to pay attention to it. This may change in the future, especially as organizations feel the need to increase their efficiency and effectiveness. But, for now, LCA input data simply isn’t available for the vast majority of solutions.
Luckily, there are, at least, a number of software tools (such as, www. gabi-software. com, www. ecoinvent. ch, and www. simapro. com)
available to enable LCAs, and more are being developed all the time. Some tools are more geared toward specific industries, such as the Pharos system for buildings developed by the Cascadia Region Green Building Council (www. pharosproject. net). Likewise, the Leadership in Energy and Environmental Design (LEED) Green Building Rating System (U. S.
Green Building Council 2008) also provides guidance to new building designers to improve the environmental performance of buildings (www. usgbc. org/leed). However, most industries are sorely lacking in tools specific to their needs.
While LCA tools can help developers roughly assess the environmental impacts of their designs, there are still issues that aren’t easily addressed by integrating these tools, such as quality, durability, and consistency. For example, reducing the wall thickness of a part might reduce its impact but might also drop its structural integrity beyond quality targets. Substituting a different material might make the part stronger but will create a completely different impact. These are the choices (and the attention to detail) required of designs and engineers if they hope to reduce the impact of the solutions they design.
How important is life-cycle analysis? Let’s use an example to illustrate in the following sidebar.
Which Is Better for the Environment-the Toyota Prius or the Hummer H2?
This sounds like a ridiculous comparison, doesn’t it? Most people (as well as common sense) would tell us that the Prius is definitely, even unquestionably, better than the Hummer H2 (see Figure 3.13). However, how do we actually know this? On what basis are we making this assessment? I’ve used this example because it’s a famous controversy in the sustainability world. As we found with the bag example in Chapter 2, even a one-piece product can bring up surprising issues. Consider how much more complex cars are.
TOP IMAGE:
http://www. flickr. com/photos/ rosenfeldmedia/3258981512
BOTTOM IMAGE:
http://www. flickr. com/photos/
rosenfeldmedia/3258169361
FIGURE 3.13 Which is better for the environment? It’s not always clear.
Which Is Better for the Environment-the Toyota Prius or the Hummer H2? (continued)
To do an adequate evaluation, it’s important to look at the life cycle of these products. For example, in the use phase of each (in this case, driving), it’s obvious that the Prius is better because it gets significantly better mileage (45 mpg for the Prius, 17 mpg for the Hummer). It doesn’t get much clearer than that.
But what happens if we look at the phases of each, namely, the manufacturing phase, (including sourcing raw materials and components, assembling them—often in different places—and transporting them to buyers) and the disposal phase (what happens to them when we’re finished with them, including any recycling of their components). Miles per gallon won’t help us here. How do we measure these impacts and where do we find the data?
This presents another critical challenge: customers don’t have access to this data. Again, we need to rely on experts, but in this case,
Which Is Better for the Environment-the Toyota Prius or the Hummer H2? (continued)
experts don’t have this data either. The only place to get the data (and it’s incredibly complex data) is from the manufacturers themselves, and for the most part, they don’t track this information. Even when they have partial data, they certainly aren’t sharing it. So where does that leave us?
Industry experts can estimate this data and probably get reasonably close at figuring out which is more cost-effective, but this is conjecture, not real data. And, when experts do estimate, we have to question what their intentions are. In the Prius vs. Hummer example, one industry group did just this, to controversial conclusions.[18]
This particular study showed that, when you take into account the entire life cycle of each car, the Hummer’s impact is less than the Prius. How can that be?
|
|
|
Which Is Better for the Environment-the Toyota Prius or the Hummer H2? (continued)
account the types of fuel used as well. For now, let’s just call it a wash.
In the use phase, the Prius clearly wins. Even though it carries around two drivetrains, it’s still lighter and its regenerative breaking captures otherwise lost energy. Score a big one for the hybrid.
However, once we get to the disposal phase, things flip around. Hybrid batteries use highly toxic chemicals that must be disposed of carefully. For those that get junked properly (or will when they start to get old), the costs are much higher than for conventional cars. Proper disposal or not, these chemicals represent a higher cost, both financially and environmentally.
To start, although the Prius excels in the use phase, there are questions about the manufacturing and disposal phases. The issues look something like Table 3.1.
Which Is Better for the Environment-the Toyota Prius or the Hummer H2? (continued)
|
TABLE 3.1
|
Which Is Better for the Environment-the Toyota Prius or the Hummer H2? (continued)
This last point, how many miles to rate each car at, is the focus of the controversy. It’s undeniable that the Prius excels in the use phase. It is probably a tie in the manufacturing phase (a case could be made that either is better, based on material amounts or types and the distance they travel). However, the study in question assumed the Prius would only last 100,000 miles based on the ratings on the battery (implying that the entire battery pack, a critical component, must be replaced after 100,000 miles in order to continue achieving the performance in its use phase).
Many people point to this as being unfair,[19] and, in fact, if the same numbers published in the report were amortized over 300,000 miles, just like the Hummer, the final impact scores would be very similar. In itself, this is surprising to most people who don’t know about the mechanics of
|
hybrid systems. Hybrids like the Prius are a kind of compromise. Essentially, they are an electric car with an on-board power generator that runs on gas. It’s a good compromise, based on our current expectations of car performance and the current state of technology, but it’s still a complex compromise that’s anything but ideal. Setting aside the issue of complexity, we don’t really know yet how to rate the longevity of the Prius. Surely, the body and engine should last as long as the Hummer. But how do we rate the batteries (which may last longer than 100,000 miles but surely not as long as 300,000)? Toyota’s response to the study was reactive and defensive and, rightly, challenged many of its assumptions, but it didn’t illuminate any of the questions, and it didn’t provide any data with which experts could recalculate the scores. If you read the response to Toyota’s response,7 written from the |
|
|
|
Which Is Better for the Environment-the Toyota Prius or the Hummer H2? (continued)
organization who created the study (funded by the U. S. automobile industry, by the way), it makes some important points that need to be addressed but it doesn’t make the question (or answer) any clearer.
The only way to know for sure is to have access to the data and let a lot of knowledgeable people fight over the assumptions and projections. The problem is that no one but the manufacturers has access to the data and, likely, they don’t even track the data to the level required to do a full – scale LCA. This is a serious problem because it destroys the possibility of claims on either side being validated. In essence, the experts aren’t able to tell us which is better.
There are other circumstances as well. For example, the Prius sales figures are sending a powerful message to the car industry about how interested drivers are in environmentally better solutions. That alone may be worth any difference in environmental impact.
Which Is Better for the Environment-the Toyota Prius or the Hummer H2? (continued)
It’s probably safe to say that the Hummer is worse for the environment than the Prius. (Although this doesn’t take into account other benefits buying a Prius may have, like the signal it sends to the automobile industry about environmental concerns on the part of customers.) However, the difference is probably not great, and it’s probably also safe to say that a non-hybrid five-person sedan, like Toyota’s own Corolla or Camry, may actually be better for the environment over its entire life cycle than the Prius. Even smaller cars, though not hybrids, like the Honda Civic that run on natural gas or the Smart ForTwo (at almost one quarter of the impact of the Prius) may be better overall (see Table 3.2). Again, we just don’t know because no one has access to the numbers to do a real evaluation (and none of the car companies is offering up their data).
Which Is Better for the Environment-the Toyota Prius or the Hummer H2? (continued)
|
TABLE 3.2
|
To be sure, driving any car less, carpooling, and driving more efficiently are better solutions. On the whole, driving lighter cars made closer to home is also better. But how many customers do you know who are able to source the data for where a car is manufactured—especially when most cars are made from subassemblies from all over the world?
The point is that we don’t have this data yet and even if companies have the data, they aren’t compelled to share it with us. And the data we use, and our assumptions about it, make all of the difference in our evaluations. That means we can’t make informed decisions.
Using an LCA as a tool in the design and development process requires that choices be made as to the types and amounts of materials that will be used in the product. LCA tools can be helpful in choosing among materials in the early phases of a project, but cannot be fully applied to assess the environmental impact of the finished product until it is fully specified and designed. This makes it difficult to use during the conceptual phases of development.
Shortcuts can sometimes be used to speed the process by concentrating on the biggest impacts, but this is hardly fool-proof since it’s based on assumptions that may be wrong. By looking at the largest components—and often the costliest materials—and involving experts with material impact experience, “rough guesses” of a concept’s impact can often be derived that are “good enough” for the purposes of concept selection. This is called matrix LCA (as opposed to full-scale LCA). Ecological footprint calculators, for example, work along the same principles. Proxy LCA uses average weightings of material impact with simplified accounting and is the most common type of LCA to be used by designers during conceptualization and prototyping.[20]
Despite some of the drawbacks, LCA tools are improving constantly, and they are still the best way to assess environmental and resource impact with any degree of accuracy. LCA tools focus on environmental impact, but don’t take into account the social impact of a product. We now will look at tools that evaluate social impact as well.
