The U.S. can eliminate its dependency on crude oil if the country switched to production of synthetic fuel using a combination of non-food crops, natural gas and coal, according to researchers at Princeton University.

In a paper produced by the American Institute of Chemical Engineers, researchers say their plan could also cut greenhouse gas emissions by as much as 50 per cent if non-food crops are used to produce that fuel.

The team examined the economic viability of building synthetic fuel plants and producing the fuel and compared that with importing crude oil that is costing between $60 to $100 US per barrel.

"The goal is to produce sufficient fuel and also to cut carbon dioxide emissions, or the equivalent, by 50 per cent," said Christodoulas Floudas, professor of chemical and biological engineering at Princeton. "Not only can it be done, [it can] be done in an economically attractive way."

According to the team, it would take the U.S. up to 40 years to adopt a fully synthetic fuel system and the total price would top $1.1 trillion.

"This is an opportunity to create a new economy," points out Floudas. "The amount of petroleum the U.S. imports is very high. What is the price of that?"

The focus of the paper is a technique that uses heat and chemistry to create liquid fuels from high carbon sources such as coal and switchgrass – a native North American grass common in the Great Plains. 

First developed in Germany in the 1920s, the Fischer-Tropsch process has been refined over the years — source material is heated to at least 1,000 degrees Celsius and converted to gas and that gas is then converted to hydrocarbon molecules, which are processed yet again to form a kind of crude oil.

The plan includes another step to recycle the carbon dioxide that’s being vented by the plants.

The team recommended construction of nine small, 74 medium and 47 large plants – with the large plants producing 71 per cent of the fuel. With a total of 130 synthetic fuel plants, all the transportation needs of the U.S. would be met.

Most of those plants would be clustered in the centre or southwest part of the U.S. where access to non-food crops – such as grasses and agricultural materials – are plentiful.

"Even including capital costs, synthetic fuels can still be profitable," said Richard Baliban, one of the papers’ authors. "These processes are competitive."

One of the best things about synthetic fuels is that they can be used in conventional vehicles – including ones with diesel engines with no need for modifications. And since synthetic fuels are cleaner, that would translate to an immediate cut in carbon emissions from cars currently on the road.

Vern Weekman, one of the co-authors and a former president of the institute, said the team produced the paper as a way of pressing the U.S. government into action.

"The main reason we wrote the paper is to get the planning agencies – the national academics, the Department of Energy, the Environmental Protection Agency, the Defence Department --  thinking about this," said Weekman.