Anaerobic Digestion at Sinclair Agricultural and Recycling Services

Alistair said his son Magnus has a passion for machinery and technology, and that was why the family eventually established its own anaerobic digestion (AD) plant in 2014 at the family farm at Udny, near Ellon in Aberdeenshire.

The original farming business started in 1952 when the family relocated from Orkney to Aberdeenshire to focus on dairy.

When the economics of dairy diminished, Alistair branched out by planting 400 acres of woodlands and he also developed the contracting side of the business, which expanded in the 2000s to include waste haulage and recycling services.

In 2014, the company entered the energy business with the commissioning of a 500kW AD plant. The AD operation not only accounts for the largest part of the company’s turnover today, but also most of the activity on the farm, growing grass and harvesting woodchip as biomass to feed the plant.

Alistair said that the move into agricultural contracting helped to diversify the business, but it was expanding into waste management that really helped to reshape the company.

He explained: “We were growing the business steadily by offering agricultural contracting services to farms such as sowing, mowing and combine harvesting in the region, but the business took a step change when the company was awarded a contract with the Scottish Agricultural College to take waste to Aberdeen for treatment – taking over that contract was the start of our waste programme.”

The business is not only profitable, but it also provides a circular and environmentally friendly way of dealing with waste: “We also take the finished product of the AD process, called ‘cambi cake’, which we spread directly on to farmland as it contains valuable nutrients,” explained Alistair.

“It’s produced in accordance with SEPA regulations and with 40-50 units of nitrogen and 150 units of phosphate, plus trace elements, it’s a great recycled product.”

It was the knowledge of working with AD plants that persuaded Alistair and Magnus to invest in their own plant, which started operation in 2014 with a guaranteed contract with EDF for 20 years.

With the AD plant requiring constant feeding, Magnus has taken measures to ensure that the biomass produced on the farm is of the highest quality in order to produce the greatest output for the AD plant. Such is Magnus’ strong relationship with tractor manufacturer John Deere, due to their long association through the agricultural contracting business, that he has been able to use the company’s state-of-the art data and analytics to help improve grass yields.

In addition to producing electricity, the AD plant also produces heat, which is being used to dry bought-in timber to produce woodchip for biomass boilers. This part of the business is expected to grow once the family starts to harvest its own forest resources.