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Show Overall, on a yearly basis, a plant can count on requiring additional personnel to handle the maintenance for analyzers. In addition, depending on the number of systems installed, more personnel may be required to maintain the mechanical equipment. HOW TO USE COST EFFECTIVENESS Now that we have the tools available for calculating cost effectiveness, the proper use of the analysis will be discussed. The first thing that needs to be done prior to conducting any cost effectiveness analysis is screening of alternatives. The local air quality district regulations will influence the mix of technologies that will be applicable. Cost effectiveness analysis can be used in two different types of situations: unit reduction regulations and bubble or average plant wide emission regulations. Unit Reduction Regulations In this case, the regulations require that NOx emission are reduced on a source by source basis. Once the project team knows what level of N O x reduction is required, the appropriate technological options can be developed. This analysis is generally self explanatory since technological limits determine which types of technologies to evaluate. Cost effectiveness analysis will prove to be valuable for the situation where competing technologies, capable of achieving the same required N O x reduction, are being evaluated. A word of caution about unit reduction regulations is to consider what the future holds. In many regions future regulations have become more severe or have been "ratcheted down". The problem with regulations that ratchet down is that a project may install a technology that may be obsolete in regard to achieving higher N O x reduction if the rules change. If ratcheting down has happened in your region, the project may want to plan for this by reducing N O x to some lower value with this project in anticipation of a future change. To do this, the project would extend the cost effectiveness analysis on options to reduce N O x to some lower number and compare the marginal cost difference between spending money in this project versus later. Bubble or Average Reduction Regulations Average or bubble based reduction result from regulations where the agency requires some level of N O x reductions from the entire plant. In these cases, the project must determine what the compliance plan (units to be retrofitted) will be, which is a perfect application of cost effectiveness analysis. ( For discussion purposes, these regulations can be further grouped into two categories; Less Than 5 0 % Reduction and Greater than 5 0 % Reduction. Each of these type regulations will require a different cost effectiveness analysis approach. Less Than 50% Reduction. In this case, the cost effectiveness analysis will be very conventional. The project would follow this procedure: 1. List all fired units in the plant by current NOx levels and either design or average firing rate. 2. Determine all possible technological options to reduce N O x from each unit and calculate the cost effectiveness of each. 3. Select and implement NOx technologies on fired units in order of lowest to highest cost effectiveness. This will be your compliance plan. 4. Continue to select fired units until the desired N O x reduction level is achieved. If the proje has included all factors in the cost effectivenesb analysis, it will be clear which options will be selected first. Greater Than 50% Reduction. In this case the cost effectiveness analysis becomes a little more difficult to apply since the N Ox reduction limitation of the various technologies start to alter how you use cost effectiveness. The procedure the project should follow with these types of regulations is similar to that presented above. The only exception would be that once you list all the technological options you must determine what contribution each option will make towards meeting compliance. The fundamental flaw in the cost effectiveness analysis is that it only looks at cost, as a function of N O x reduced, not the resultant N O x level. For regulations requiring plant wide average N O x reductions greater than some individual technologies can provide, the analyst much use some other means in conjunction to the cost effectiveness analysis to determine the most effective compliance plan. In many cases, this ; where a series of trial and error options must li evaluated to ensure the most cost effective compliance plan. Again, the actual reduction KTI CORPORATION, CONCORD THE REAL COST OF NOx EMISSION REDUCTION AFRC/JFRC 1998 SYMPOSIUM |
