Our computer simulations have shown that our four main attributes of greenhouse gas emissions, oil consumption, air pollution and total societal costs all follow the same pattern:

• Hybrid electric vehicles (HEVs) make modest reductions in each attribute
• Plug-in hybrid electric vehicles (PHEVs) further reduce each attribute
• BIomass-powered PHEVs cut pollution and societal costs even further
• Hydrogen-powered fuel cell electric vehicles (FCEVs) cut pollution and societal costs the most, and FCEVs are the only major option that can achieve the goal of 80% reductions in GHGs below 1990 levels
• Battery-powered electric vehicles (BEVs) could reach an 80% reduction in GHGs later this century, assuming that affordable batteries could be developed that could be used for all light duty vehicles including SUVs, vans, and light duty trucks even with limited range and long refueling times.
• Hydrogen-powered hybrid electric vehicles. Similarly, hydrogen HEVs might achieve the 80% reduction in GHGs toward the end of the century if most LDVs could be converted to hydrogen. Indeed, the hydrogen HEV would reduce GHGs faster than BEVs due to the length of time it takes to reduce the carbon footprint of the existing electrical grid, whereas hydrogen made from natural gas immediately cuts GHGs even before lower carbon and renewable hydrogen enters the mareketplace.