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Will your Fuel-Efficient Car Pay for Itself? Ask the Clean Car Calculator.
Bren course gives rise to cost-comparison tool

With gas prices high, more people are shopping for high-efficiency vehicle, and that leads to comparison shopping. But how do you know if an electric car, a hybrid, or a fuel-efficient gasoline vehicle is the best deal in the long run? Does it make sense to purchase a high-efficiency vehicle? And which one is best?

Now, thanks to the efforts of Bren assistant professor Sangwon Suh and a team of students in his Energy and Resource Productivity course, it's easy to find out by using the "Clean Car Calculator."

The tool grew out of a class assignment in which Professor Suh had students compare two vehicles — one having a conventional gas engine and the other a high-efficiency engine — in terms of their total lifetime costs. Since then, it has been expanded so that anyone can calculate the lifetime cost of any car and compare it with the lifetime cost of other cars.

This net present value (NPV) calculation yielded surprising results. Most of the students had anticipated that purchasing a high-efficiency vehicle, such as a Toyota Prius or Chevrolet Volt, would cost more over the lifetime of the vehicle (i.e. that savings from the higher fuel efficiency would not be enough to offset the higher upfront cost of the vehicle).

Instead, writes Christin Chen on the website, "We were surprised to find not only that established hybrids paid themselves back in fuel savings, but also that newly released vehicles, such as the Volt and the Leaf, were extremely affordable to begin with."

As a result of the initial findings, Professor Suh formulated a team of students to delve deeper. Over the course of five months, Phd candidate Zack Donohew and Christine Chen, Jake MacArthur, Ryan Smith, and Brock Treece (all MESM 2011) gathered data, tested assumptions, and constructed a comprehensive spreadsheet calculator that would compare the total lifetime costs of any two vehicles.

With funding from th eBren School and the UCSB Institute for Energy Efficiency IEE), the team designed and then commissioned CleanCarCalculator.com to share these interesting results. The resulting website was created to simply and robustly communicate that high-efficiency vehicles are an affordable option that will save consumers money over time.

The calculator has fields for entering such information as the make and model of car, average annual mileage, and the type of driving you do most often. There are also fields for more detailed information, such as the average distance between charging stations in your area. Realizing that most people don't know that, the team provided default values so that users can use the calculator using only basic information.