A National Research Council report determined that the US can achieve this goal with continued pursuit of biofuels and hydrogen, strong government policies, and more efficient vehicles on the road.
Specifically, alternative options to petroleum that are cost effective and have low emissions of greenhouse gases must be a viable and affordable option. The transition to a more sustainable and ecofriendly model will be costly, initially, and that has often been prohibitive and discouraging to individual and businesses alike.
Vehicle efficiency is probably the easiest of the solutions to attack. Engine redesign, reduced vehicle weight, aerodynamic design, and improve efficiency o the internal combustion engine powertrain can all contribute to lowering automobile emissions significantly.
If automobile design is combined with one of three alternative power sources like electricity, hydrogen, or biofuel, emissions could be lowered to an even greater degree.
To date, biodiesel and corn-grain ethanol are the only biofuels produced in commercial quantities in the U.S. to date. The study determined a much greater potential in biofuels made from lignocellulosic biomass, essentially biomass made up of crop residues like entire trees, wood waste, wheat straw, and switchgrass.
A necessary consideration surrounding electric vehicles is their load on the electric power grid. Electric vehicles are also reliant on batteries, which will most likely to become less costly in coming years. However, recharge times and limited range will be a deterrent to many consumers.
Hydrogen used as fuel cells in electric vehicles only emits water, but some greenhouse gases are emitted during the production of the hydrogen itself. Methods to produce hydrogen in a low-greenhouse gas manner are more expensive and not currently competitive with other options in the market. It’s possible that by 2050 hydrogen fuel cell vehicles could become cheaper than sophisticated combustion engine vehicles, but the technology behind hydrogen needs to evolve to do so.