are using what is known as Tier 2 diesel engine technology which is outdated and in need of upgrading . The use of Tier 2 diesel engines in these vehicles results in significant emissions , negatively impacting airside air quality at the airport .
As a result , the Authority has been evaluating its options to electrify these vehicles over the coming years subject to availability of both internal and external funding . We hosted Industry Days in both 2019 and 2020 with large vehicle manufacturers to explore the various electrification options at our disposal and expect to issue a formal Request for Proposal in 2020 . Any effort to electrify these vehicles is longer term in nature ; we will need to finance the development of a prototype first to ensure that these unique vehicles will work as effectively as our original systems before committing to large-scale production .
If we determine that electrification of the PTVs is not a feasible alternative at this time , either due to a lack of funding support from the Federal Aviation Administration ( FAA ) or technical limitations of electric PTVs and their ability to meet our daily service requirements for passengers at Dulles International , the Authority will then upgrade a certain number of PTVs to newer , Tier 4 , diesel engine technology . 9 This upgrade will have air quality benefits and reduce our operating costs associated with these vehicles .
Benefits of Upgrading to Tier 4 Diesel Technology
Updating to current diesel emissions technology ( Tier 4 ) will not result in the degree of air quality improvements and fuel savings expected from eventual electrification . However , the benefit of phasing out older technologies is significant with drastic reductions in visible emissions and other invisible contaminants . A summary of what we have calculated as the benefits of upgrading to Tier 4 technology is as follows :
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Nitrogen oxides ( NOx ): 95 % reduction in tailpipe emissions � Particulate matter : 95 % reduction in tailpipe emissions � Sulfur oxides ( SOx ): 0 %– 5 % reduction in tailpipe emissions 10 �
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Reduction in annual diesel consumption by approximately 5 % which translates into a modest reduction in CO 2 emissions Improvement in air quality for employees , passengers , and the broader community Reduction in operational costs and frequency of breakdowns
Our base case assumption is that it will cost approximately $ 200,000 to upgrade each of the PTVs to Tier 4 technology implying a total investment of $ 9.2 million dollars were we to upgrade all 46 vehicles . However , only a certain percentage of the fleet will be upgraded if we choose this strategy with the remaining vehicles being designated for decommissioning . In return for such an investment , we would expect material savings in operations and maintenance ( O & M ) costs and a modest reduction in diesel fuel consumption . However , it is the opportunity to further save on O & M and eliminate diesel use in the PTVs that motivates us to pursue electrification .
9 Tier 4 relates to U . S . Environmental Protection Agency regulations regarding minimum emissions requirements for diesel engines . 10 The current use of low-sulfur diesel fuel already minimizes the emissions of SOx .
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