Heat engine/electric hybrid passenger vehicles have been shown in five independent studies to have potential for substituting electrical energy for 40% to 80% of the petroleum fuel consumed by conventional ICE passenger vehicles. The hybrids were projected to exceed their conventional counterparts in initial coat (purchase price) by 21% to 62%, but be much more competitive In terms of life-cycle costs: 0-27% greater than the conventional counterparts. Hybrid versus conventional cost comparisons varied significantly among the five studies. All five found the cost competitiveness of the hybrid to be inversely correlated to its petroleum fuel displacement capability and highly sensitive to petroleum fuel prices with all five selected hybrid designs achieving break-even life-cycle cost at petroleum fuel prices of $2.70 per gallon (in 1978 dollars) or less.
