He runs Biobean, a start-up which is gathering waste from coffee chains such as Costa and converting it into liquid fuel.

Bio-fuel will be crucial to that," said Mr Kay.

"As long as people are still drinking coffee, there will be coffee waste.

"In the UK, people consume 500,000 tonnes of coffee each year, and if we could use all of it we could power a city such as Manchester," he said

Lots of countries are starting to see the benefits of bio-fuel, which can be made out of anything from chocolate to sewage.

Initially bio-fuel was created from ethanol - which is generated from Brazilian sugar cane - but following concerns in the mid 1990s that this was unsustainable because it was also a food source - the country focused more on bio-gas, made as a by-product of methane in sewage.

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