Essex potato farmers Laura and Robert Strathern, who diversified into crisp making are celebrating the opening of a new anaerobic digestion (AD) plant. Fairfields Farm at Wormingford, near Colchester, believes the investment, which means the business is entirely energy efficient, makes it the UK’s only hand-cooked crisp company powered solely by renewable energy. The plant, which occupies the space of about 10 football fields, took two years to plan and build. It is situated right next to the farm’s crisp factory and its potato fields. It digests organic matter, such as waste potatoes and crops such as maize and rye, and trillions of microorganisms anaerobically digest this to create gas. Special varieties of crisping potatoes are grown to make Fairfields Farm crisps, which are now exported to 20 countries around the world. More product launches are planned this year. More. Watch video