Ranking the Options

Ranking and prioritizing these options required specific quantitative and sometimes qualitative data about each choice. Table VI provides estimated reduction in re- 

5a Install Sec. Seals on Gasoline Tanks 474.7 75.0 7 Source reduction 

6 Decrease Soils in Drainage Systems 530.0 50.0 4-7 Source reduction 

10 Sour Water System Improvements 18.0 100.0 1-3 Recycle/treatment 

AMOCO/EPA Pollution Prevention Project Financial Summary 

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Now that you have determined the likely savings in terms of annual process and waste-treatment operating costs associated with each option, consider the necessary investment required to implement each option. Investment can be assessed by looking at the payback period for each option that is, the time taken for a project to recover its financial outlay. A more detailed investment analysis may involve an assessment of the internal rate of return (IRR) and net present value (NPV) of the investment based on discounted cash flows. An analysis of investment risk allows you to rank the options identified. 

It might seem that, when there is a conflict of interest, majority voting will elicit or indeed constitute the popular will. But this proposal doesn t hold water. Suppose there are three blocs in the assembly, of approximately equal size, representing the business community, industrial workers and health and social service professionals. Let us also suppose that, conforming to the stereotype of these groups, they rank the options as follows ... 

Using these four factors to evaluate each chosen option will result in each option receiving a score. This score will rank the options from highest to lowest. This will produce an order for further exploring these options. 

Developing a system for evaluating and ranking the options in light of cost, risk, regulatory requirements, and other factors. 

Practical use of hydrogen in vehicles may never happen until there is a better method to store hydrogen, especially since onboard reforming of hydrogen at a reasonable cost may not be a possibility. The U.S. Department of Energy has worked with the auto industry and has ranked the options for hydrogen storage. The best candidate so far is compressed gas at pressures of about 700 bar. While not an ideal solution, it is probably marketable. 

One proposal focuses on a system known as Applications for the Environment Real-Time Information Synthesis (AERIS) that would help people make decisions about the best and most efficient mode of transportation to use for a particular trip. Under the proposal, AERIS would provide information comparing current travel times from one point to another depending on the mode of transportation. The information would be drawn from traffic data on highways and roads, public transit schedules, up-to-the-minute information on delays, and weather data. The system s interface might list a traveler s options by transportation mode, ranking the options by travel time, cost, or carbon footprint. These options could be viewed on a mobile device such as a cell phone. 

Because some sort of valuation and ranking of options always have and always will take place in decision making. The choice is between using economic values derived in a consistent and transparent way (environmental economics approach), or to use arbitrary and random economic or other values estimated in a case-by-case setting. And the authors of this chapter are in favour of a transparent approach that is open for improvements. 

Cases in which, for given beliefs and desires, there is no optimal action arise when people are unable to compare and rank all the options. If there are several actions than which none is better, I may be unable to say which of them I prefer am/ also unable to say they are equally good. This is incommensurability, not indifference. A simple test allows us to distinguish between the two. Assume that, for two options x and y, I have no preference for either. If I am indifferent between them, I should always prefer x together with an extra dollar every. If however, I do not prefer x-ptus-a-dollar over y. it shows that x and y are incommensurable. 

A variety of factors and methods were used to evaluate and rank the twelve options. For example, the study team considered the reduction in relative risk to human health achieved by different options. Generally, an option s effectiveness in reducing health risks was evaluated by calculating its effect on exposure to benzene emissions. The study team selected benzene emissions as an indicator because benzene can be found in all waste media (air, water, groundwater, and surface water) and poses a known threat to human health. 

When reducing benzene emissions was considered to be the primary goal, the study team calculated that six high-ranked options together reduced benzene exposure by 90% at an annual cost of 4.5 million. This was only 20% of the annual cost of all the options mandated by regulation. 

Rank and prioritize the options using a variety of criteria and perspectives. 

The project s Peer Review Committee suggested the options be ranked according to a single criterion risk reduction. In addition to risk reduction, two other single criterion rankings are of interest total tonnage reduction and cost. 

Fourth, evaluate each option within the context of the proposed hierarchy. Overall scores are determined for each option based on its performance on the criteria in the hierarchy. A comparative ranking of options among themselves is thereby established. 

Table XIII presents the results of the AHP ranking using the hierarchy and criteria weights developed by the study team. There appear to be three distinct groupings of options most preferred, least preferred, and a middle ground where no strong preference exists for one choice over another. Two major factors influenced the overall ranking of options exposure reduction and cost. Technical characteristics determine the rankings within the mid- and low-performance groups.

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