It's both exciting and frustrating living in the current automotive age.

Exciting, because we're truly seeing an eclectic mix of powertrain technologies being developed, the fruits of which we're increasingly able to drive. And frustrating, because there's still no surefire way of knowing what we'll be driving in the future.

The U.S. Department of Energy (DoE) thinks that future energy mix might not involve petroleum though--which could disappear entirely from the transport sector by 2050.

That's according to a new report as part of the Transportation Energy Futures project (via Green Car Congress). As well as the disappearance of petroleum, greenhouse gases could be reduced by 80 percent.

There's a number of factors which influence the above statistics, not least a reduction in use compared with today. Higher prices are likely to account for some of that, but the report also says changes in built environments could be a factor--improved public transportation, technology allowing more people to work from home, and more.

That's already happening in Europe, where many city centers will be zero-emissions by 2050. "Carbon taxes" for regular vehicles and incentives for electric transport is already making some centers fossil-fuel unfriendly--and it's only likely to increase over the next few decades.

A mixture of other technologies will help reduce demand further, including increased use of electric and hydrogen vehicles. Shell's CEO has previously stated that 40 percent of vehicles will be electric by 2050, and another report says that 7 in every 8 vehicles sold in California could be zero-emission by 2050.

Other powertrains could make up  much of the rest. Liquid fuel won't disappear altogether, either--biofuels will take the place of fossil fuels in areas where liquid fuels are essential.

That includes the jet fuel market, where up to 50 percent could be biodiesel (a process already in motion with the first part-biofuel route now in service) even at pessimistic estimates. Of course, these figures will have to struggle against a likely increase in air travel, and other "non-light duty vehicles" such as trucks and ships are also expected to increase in numbers, making the task a difficult one.

At the optimistic end, a prior report predicts the vast majority of all energy produced could in fact be green energy by 2050.

In reality, the actual figure is likely to be somewhere between the two, unless there are significant, unforseen advances in technology by then. Which is always possible, but never a certainty.

There is a lot of work to be done--the transportation sector accounts for 71 percent of total U.S. petroleum consumption, which is quite a habit to kick. It also emits 33 percent of the country's carbon emissions.

In an ideal world, the path would be easy to follow. But then, few things worthwhile are ever easy--and kicking our fossil fuel habit in the next forty years is certainly a worthwhile goal.


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