Tomatoes are usually best kept for salads or a bloody Mary but one tomato grower in the North of England has found another way to use them – to generate power from their leaves using anaerobic digestion.
Instead of sending them to landfill at a cost of £100,000 a year, the two and half thousand tonnes of waste tomato leaves are being converted into biogas.
The leaves are fed into a hopper and chopped by a macerator, them chopped up by a pump to break down the organic plant material in a reception tank – otherwise their natural healing ability would make the matter go solid, according to Landia, the pump manufacturer behind the hopper.
Then it is heated and broken down into a bright green liquid to be used in the anaerobic digestion plant.
Gas produced from the plant currently provides around 10% of the energy needed for the tomato producer’s 2.5MW operation, which is roughly enough to power around 2,500 homes.
Paul Davies at Landia said: “This isn’t a typical sludge-like digestate you find at most anaerobic digestion systems where in some cases there seems to be a very non-scientific, ‘chuck everything in’ approach… Everyone has had to be extremely patient. Record-breaking gas yields are not going to happen here.
“However, this definitely isn’t going to be one of the increasing number of AD plants that are finding feedstock difficult or increasingly expensive to obtain,” he added.