Waste tea leaves would make a good biofuel, according to a recent Pakistani study.

The researchers were able to reduce waste tea leaves into a bio-diesel suitable for powering engines, using nanotechnology.

The nanotechnology involved in the study is a nanocatalyst, and greatly accelerates reaction times wherever it is used.

Study co-author Tajamul Hussain said that the world today consumed several million tonnes of tea yearly, and that the method his team invented could could some day produce alternative energy.

For the purposes of the research, the scientists first converted regular waste tea leaves into a gas.

They mixed the spent tea leaves with the nanocatalyst, which is based on cobalt.

The researchers extracted the product of that reaction, in liquid form, and processed it even further.

The result of the entire reaction was a 40% bio-diesel.

The reaction also produced ethane, methanol, methane, and charcoal.

The researchers said that the extra gases could also be used as fuel, while the charcoal could be used in agriculture or in water filtration.

The only problem with the method that uses nanoparticles to convert the tea leaves into biofuel is that it very costly.

Kausar Malik of Forman Christian College in Lahore, who did not take part in the study, said that the study did not reveal anything new to scientists.

He said that the cost of making biofuel with tea leaves was more than the value of the energy produced.

In search of a cheaper option, the research team also attempted to formulate a bio-diesel fuel using a fungal fermentation process.

Using that process, the researchers were able to make a 57% bio-ethanol fuel.

Malik said that there were many kinds of potential biofuels, and that the tea leaf study did not provide an economical option to for industrial applications.

Hussain disagreed and said that tea was more efficient than other materials being considered for use as bio-fuels.

He said that the process his team had studied was less costly in the long run, and that the first batch of bio-fuel it produced was the only one that required high amounts of energy.

China, India, Kenya, and Sri Lanka are the world's main exporters of black tea.

About 4 million tonnes of black tea are produced each year.