A Cumbrian environmental specialist has completed its biggest shipments of "green" oil, which will be used as a hi-tech aviation fuel.
In its first four full ocean tankers, the Leo Group has shipped 10,700 tonnes of tallow recycled at its Omega Proteins plants at Wildriggs, near Penrith, and Bradford in West Yorkshire.
This accounts for 10,700,000 litres of oil.
The tallow, a natural by-product rendered from animal waste collected by the company from all over the UK, is a key component in the process to create an advanced form of biodiesel.
The overseas shipments come as the company marks another environmental milestone.
The tallow and poultry oils produced at both rendering plants are now certified under the International
Sustainability and Carbon Certification (ISCC) scheme.
The ISCC seal is used by industry to distinguish between truly sustainable and unsustainable biomass fuels.
Leo Group managing director Danny Sawrij said: "We are delighted that customers around the world are drawing upon our expertise to drive down the world's carbon footprint.
"Waste is not in the Leo Group's vocabulary or culture – everything these days has a use and 100 per cent of all by-product materials on our sites are now recycled.
"A few years ago, a dead sheep would be buried in the ground with the risk of contamination.
"Now we can turn that sheep into diesel and electricity – you can run your car on it and turn your lights on. That is how far we have come."
There has been a push in recent years from the EU to increase the use of biofuels in the world's energy mix to reduce reliance on traditional fossil fuels, with their associated greenhouse gas emissions.
Biodiesel is proven to reduce greenhouse gas emissions by up to 90 per cent compared to traditional fossil diesel. However, not all biofuels are sustainable. Unsustainable biofuels can cause significant
environmental damage, the most obvious example being the clearance of virgin rainforest to grow oil plants such as palm oil.
In judging sustainability, the ISCC audit and certification process assessed , protection of natural habitat and social sustainability.