Reducing global warming from county vehicle fleets  

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Baltimore County, Maryland’s fleet of 1,500 light-duty vehicles emits an estimated 7,000 metric tons of CO2 per year.  

The CO2 enters the atmosphere and causes the outgoing “thermal” radiation, which is naturally emitted by the Earth, to be reflected to Earth. The reflected radiation results in increased temperatures that cause increased frequency of coastal flooding and stronger storms in the Baltimore area. This is known as the “Green House Effect.” 

To reduce Baltimore County’s contribution to global warming, the municipal government seeks to transition the vehicle fleet from fossil fuel Internal Combustion Engines (ICE) to no or low carbon emission vehicles. 

A team of systems engineering students worked with Baltimore County staff in more than six departments. For their project entitled "Design of a Decision Support Tool for Developing EV Fleet Transition," the team of Evan Anderson, Khiem Duong, Rebecca Quintero, and Hein Naing won first place in the Social Engineering Track at the Fourth Annual Andrew P. Sage Memorial Capstone Design Competition.

“It’s a lot more complicated than you would think,” says Rebecca Quintero. “Like most organizations, the county has strict accounting practices for purchasing vehicles. These practices account for only the acquisition costs, not the total life-cycle costs.” The team worked with county personnel across departments to modify the purchasing and acquisition process to consider total life-cycle costs. 

“The difference between acquisition costs and total life-cycle costs is very important,” says SE team member Khiem Duong. “Electric vehicles are more expensive to purchase but have lower operating costs than fossil fuel-burning vehicles. Electric vehicles have fewer moving parts, so their maintenance costs are lower. Also, electricity costs for charging the vehicle batteries are lower than gasoline costs. The total life-cycle cost model is complex.” 

“The other complexity is in the choice of vehicle and charging station infrastructure,” says team member Evan Anderson. “There are three categories of electric vehicles: hybrid ICE/Electric, plug-in hybrid, and plug-in electric. Each department has different vehicle needs that can be serviced best by one category, manufacturer, and vehicle model. There are also different types of charging stations.” 

The team developed and thoroughly tested a decision support tool (DST) that allows non-technical department personnel to provide information on how the vehicles are used, cabin and cargo space, carrying loads, towing capacity, and other attributes. The tool then uses forecast gasoline and electric costs, estimates of CO2 emissions, estimated maintenance costs, and more to generate a ranked list of recommended vehicles and their acquisition and total life-cycle costs. 

The DST is in use by Baltimore County staff. Seth Blumen, Baltimore County energy and sustainability coordinator, says, "The thorough assessment and detailed analytics provided in a user-friendly tool has helped the county tremendously. We can now explore options for which vehicles to consider meeting sustainability goals. It was a privilege to work with such a sophisticated and dedicated team." 

“The project is not over,” says SE team member Hein Nang. “We have developed a business plan and hope to create a start-up to provide the tool and consulting services to other municipalities to make the safe and cost-effective transition to electric vehicles.” 

“We are very proud of systems engineering students,” says Systems Engineering and Operations Research Department Chair and Professor John Shortle. “These are complex system problems that require sophisticated engineering and analytical skills. This project, and other SE senior design projects, show how graduates from this department are making the world a better place one project at a time.” 

Advising for this senior design project was provided by Systems Engineering Associate Professor Lance Sherry and Professor George Donohue.