Project Phases - Phase I

The first phase of the Plug-in Hybrid Electric School Bus Project required us to gather information and demonstrate the feasibility of the technology. We consulted industry experts, school bus fleet supervisors and regulatory agencies. This group formed an advisory panel to guide us and help answer questions.

Our gathering of experts agreed that the notion of a plug-in hybrid electric school bus had great potential. But would hybrid technology really work specifically for school buses? One option was to build a prototype and gather test data. But our goal is to change the marketplace and we felt that goal could not be achieved through another prototype demonstration. In order to convince a major school bus manufacturer to produce these vehicles, we had to approach the problem the same way they would. That required using software simulation to evaluate the options and determine an optimum configuration. The result of our efforts was the technical feasibility study.

To model the performance of a plug-in hybrid electric school bus, we used software called ADVISOR developed by the National Renewable Energy Laboratory. Most major manufacturers use this program to simulate hybrid and other advanced vehicle drive systems. It requires a wide variety of technical information and inputs such as drive cycles, emission profiles, engine specifications, accessory load, vehicle dynamics, battery type, passenger weight, and motor specifications.

The results of this modeling showed that hybrid drive systems would significantly improve fuel economy and emissions over a conventional school bus. This study also demonstrated that plug-in hybrid school buses would have improved performance over standard hybrids. The full technical feasibility study can be downloaded here.

But just because a technology will perform well does not mean that it is cost effective. This need to demonstrate economic viability led to a business feasibility study. Using standard life-cycle costing methodology, we compared the present value of all the costs and benefits associated with a conventional school bus, a hybrid electric school bus and a plug-in hybrid electric school bus. The analysis compared initial costs, fuel costs, maintenance costs and the benefit of avoided emissions. The report included a spreadsheet that allowed school districts to enter data specific to their operations and compare life-cycle costs using their local price for diesel fuel, their local maintenance costs and other specific data. The analysis demonstrated that the higher initial cost of a plug-in hybrid electric school bus is recovered within the lifetime of the vehicle through reduced operating and maintenance costs. The full business feasibility study can be downloaded here.

The Technical Feasibility Study and the Business Feasibility Study include many details that are not of interest to a general audience. In order to convey our message in a less technical manner, we authored an overall Feasibility Study. This document reviews the reasons behind the project: air quality and dwindling oil supplies. It also summarizes other technologies that reduce pollution or reduce petroleum consumption. That report may be downloaded here.

As the project developed, the advisory group decided to pursue a group purchase of plug-in hybrid school buses and formed a subset of school districts. This Buyers’ Consortium consisted of districts, state agencies and other purchasing entities. Members agreed on their common purpose to gather funding, write a technical specification and issue a Request for Proposal (RFP) to the school bus industry. Representing 20 buses and 11 different states, members of the Buyers’ Consortium worked diligently for several months and issued the RFP in June 2006.

Advanced Energy would like to thank the organizations that sponsored this phase of our project and enabled us to start the transformation of the school bus market. These groups include Duke Energy, Progress Energy, Dominion North Carolina Power, the Electric Cooperatives of North Carolina, and the North Carolina State Energy Office.