Global coal waste could be used to provide energy equivalent to 70% of Saudi Arabia’s oil reserves.

That’s according to energy company Arq, which claims its technology could convert this waste into a low carbon feedstock.

It has already patented the process and secured $175 million (£129.5m) of funding to roll out the technology.

The product uses micro-fine hydrocarbons to convert coal into oil products mechanically, rather than chemically, which has historically proved economically unviable and environmentally damaging.

The firm says the resulting fuel particles are so pure and small they can be blended directly into oil products, without the need for expensive liquefaction, keeping costs low.

Arq estimates more than one billion tonnes of coal waste are created each year, equivalent to throwing away around five million barrels of oil per day.

Julian McIntyre, Founder and CEO of Arq, said: “Coal is the world’s most abundant and lowest cost fuel, with more than 10 billion tonnes of waste lying discarded in the US alone.

“That gives our cutting edge technology an extensive, environmentally beneficial and low cost feedstock from which we are making these valuable fuels.”