MONTREAL, Dec. 9 (UPI) -- Researchers at McGill University say today's clean energy technologies -- lithium batteries and hydrogen gas -- won't be able to entirely replace fossil fuels. They need help.

According to a new study published in the journal Applied Energy, metal powders could be the future of transportation power and the global energy trade.


"Biofuels can be part of the solution, but won't be able to satisfy all the demand; hydrogen requires big, heavy fuel tanks and is explosive, and batteries are too bulky and don't store enough energy for many applications," lead study author Jeffrey Bergthorson, a mechanical engineering professor at McGill, said in a press release. "Using metal powders as recyclable fuels that store clean primary energy for later use is a very promising alternative solution."

Bergthorson and his colleagues are spearheading new research into the use of metal powders in external combustion (EC) engines. Motor vehicles mostly rely on internal combustion engines, which incorporate the fuel source. EC engines are powered by an outside heat source.

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EC engines have a long history. The heat and steam of burned coal powered the steam engines of ships and locomotives throughout the 19th century. Today, modern EC engines convert nuclear energy or biomass into electricity.

Researchers at McGill pinpointed metal powders as an ideal EC engine combustible because, when burned, they react with oxygen to create stable, nontoxic solid-oxide byproducts. Unlike the CO2 pumped into the atmosphere by today's cars, these byproducts can be collected relatively easily and recycled.

To prove the potential of their ideas, researchers built a small model burner and successfully stabilized a flame in tiny stream of iron powder particles suspended in air. Iron is the ideal metal, because iron powder is already used in a variety of industrial applications, making it easily recyclable.

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"The energy and power densities of the proposed metal-fueled heat engines are predicted to be close to current fossil-fueled internal combustion engines, making them an attractive technology for a future low-carbon society," researchers wrote in their new paper.

Bergthorson and his research partners are now preparing to build a heat-powered engine using their new burner technology.

"We are very interested in this technology because it opens the door to new propulsion systems that can be used in space and on earth," said study co-author David Jarvis. "The shift away from fossil fuels for vehicle propulsion is a clear trend for the future."