Washington, July 28 : The vegetable oil that is often discarded as waste by restaurants and pubs could be a vital source of hydrogen, and therefore, fuel - says a new study.

Although it's a greener fuel, making hydrogen may consume vast amounts of energy, use scarce natural resources, or spew out high levels of greenhouse gas.

Researchers at the University of Leeds have found a new method that uses waste vegetable oils to produce hydrogen through a process that is carbon neutral.

Dr Valerie Dupont and colleagues have perfected a two-stage process that is essentially self-heating.

Nickel catalyst is blasted with air to form nickel oxide - raising temperature of 650 degrees by another 200 degrees.

The fuel and steam mixture then reacts with the hot nickel oxide to make hydrogen and carbon dioxide.

A special ''sorbent'' material traps all the carbon dioxide produced, leaving pure hydrogen gas.

This trick eliminated the greenhouse gas emissions and also forced the reaction to keep running, increasing the amount of hydrogen made.

"So as well as the generation of heat, this is another way that makes the process very efficient," said Dupont.

"The beauty of this technology is that it can be operated at any scale. It is just as suitable for use at a filling station as at a small power plant," Dupont said.

"If we could create more of our electricity locally using hydrogen-powered fuel cells, then we could cut the amount of energy lost during transmission down power lines."

The study will be published in the journal Bioresource Technology. (ANI)