The number of UK anaerobic digestion (AD) plants turning old food scraps and farm waste into energy has grown 34 per cent this year, with 2.55 million tonnes of organic material now being processed each year.

According to a survey carried out by the Waste and Resources Action Programme (WRAP) and released yesterday, the number of operational AD plants in the UK reached 117 this year, while the number of people employed by the sector rose to 482.

However, the organisation, which this week secured charitable status, warned the technology is still far from reaching its potential. The government has estimated the UK's 100 million tonnes of organic waste could generate up to seven per cent of the country's renewable energy needs by 2020 through the use of AD.

Perhaps controversially, at a time when the food industry is under pressure over the amount of food the UK is wasting, the figures show food manufacturers and processors provide two-thirds of feedstock to AD plants.

But encouragingly, the survey also reveals local authorities have increased the amount of organic waste they send to AD by one-third, suggesting the number of councils collecting food waste is on the rise and that their reporting on food waste processing is improving.

Ian Wardle, head of organics and energy at WRAP, welcomed the positive trends uncovered by the survey.

"The industry is turning a wide variety of wastes into valuable renewable energy and digestate that can be used by farmers as a fertiliser," he said in a statement. "Each year we are seeing the sector grow and this year's data shows the AD industry is starting to make a marked contribution to the UK economy. Industry has always supported this survey and this year's excellent response is testament to that."