The most well-known reason of global warming is equivalent carbon dioxide (CO2equ) emitted from fossil fuels combustion in on-road and off-road vehicles. An appreciable portion of off-road pollution is allocated to farm implements. All cited studies have shown that renewable based electric vehicles (EVs) decrease petroleum consumption and consequently reduce criteria emissions under nearly all circumstances. Considering this, a Solar Assist Plug-in Hybrid electric Tractor (SAPHT) was designed, constructed and evaluated. This research evaluated the life cycle analysis of SAPHT project and compared the results with that of an internal combustion engine tractor (ICET). The life cycle was analyzed based on economical cost and environmental emissions. The externality of environmental pollutions was calculated to derive the life-cycle costs (LCC). The results showed that substituting each ICET by SAPHT can prevent 14 ton CO2equ emission to atmosphere annually. Also it prevents a high volume of other emissions such as CO, NOx and PM10 entering the atmosphere. LCC assessment emphasizes on economical effectiveness of SAPHT rather than ICET at any diesel fuel price, therefore, increasing fuel unit prices leads to more effectiveness. It is concluded that levelized cost of energy (LCE) in (sic)/kW h for ICET is almost twice as that of SAPHT. Some of these advantages for SAPHT are offset in part by high purchase costs, heavy and massive batteries and low operating range. (C) 2010 Elsevier Ltd. All rights reserved.