Abdelhamid, M., Haque, I., Pilla, S., Filipi, Z. et al., "Impacts of Adding Photovoltaic Solar System On-Board to Internal Combustion Engine Vehicles Towards Meeting 2025 Fuel Economy CAFE Standards," SAE Int. J. Alt. Power. 5(2):237-248, 2016, doi:10.4271/2016-01-1165.
The challenge of meeting the Corporate Average Fuel Economy (CAFE) standards of 2025 has led to major developments in the transportation sector, among which is the attempt to utilize clean energy sources. To date, use of solar energy as an auxiliary source of on-board fuel has not been extensively investigated. This paper is the first study at undertaking a comprehensive analysis of using solar energy on-board by means of photovoltaic (PV) technologies to enhance automotive fuel economies, extend driving ranges, reduce greenhouse gas (GHG) emissions, and ensure better economic value of internal combustion engine (ICE) -based vehicles to meet CAFE standards though 2025. This paper details and compares various aspects of hybrid solar electric vehicles with conventional ICE vehicles. Different driving locations, vehicle sizes, various driving patterns and different cost scenarios are used in order to enhance the current understanding of the applicability and effectiveness of using on-board PV modules in individual automobiles and ensure an accurate representation of driving conditions in all U.S states at any time. These times and location-dependent results obtained over a year show an increase in the combined mile per gallon (MPG) at noon in the range of 2.9-9.5% for a vehicle similar to a Tesla S, and a significant increase in the range of 10.7-42.2% for lightweight and aerodynamic efficient vehicles. In addition, by adding on-board PVs to cover less than 50% of the projected horizontal surface area of a typical mid-size vehicle (e.g., Toyota Camry or Nissan Leaf), up to 50% of total daily miles traveled by an average U.S. person could be driven by solar energy. Also, the return on investment (ROI) of adding PVs on-board with ICE vehicle over its lifetime shows only negative values when the price of gasoline remains below $4.0 per gallon and the vehicle is driven in low-solar energy area (e.g., Boston, MA). The same ROI is more than 250% if the vehicle is driven in high-solar energy area (e.g., Arizona), even if the gasoline price remains low. For future price scenarios, this ROI is much higher - nearly 10 times the investment cost under some scenarios, with the assumption of an eventual decline in battery costs. With regard to environmental impacts, significant gasoline gallons savings (∼500-3400) and CO2 emission reduction (∼5.0 to 34.0 short tons) are achieved.