Potato sector can make big energy savings

Massive savings can be achieved by improving energy efficiency to store the country's potato crops, said a leading researcher.

Adrian Cunnington, of the Sutton Bridge Experimental Unit, estimated that the industry could cut annual energy costs by £11m as half the country's production is stored after harvest.

The best stores were about four times more efficient than the average, which spent about £5 per tonne in the year to April, he calculated. A survey of 33 stores last season, including several in Norfolk, revealed a ten-fold difference between the best and the worst.

The energy efficiency project, which was now in its third year, had identified a huge range of store performance, said Mr Cunnington. "This suggests there's a staggering potential for many growers to save a considerable sum.

"With 55pc of the crop or between 3.5m tonnes and four million tonnes stored for some considerable period, that's a huge goal.

With typical weight losses in store of about 4 or 5pc, then further problems with condensation and changing quality during storage could reduce the value by as much as 10 to 15pc of total production.

He urged growers to check crops, which had been damaged during harvest. "We're already aware of some crops not being taken in because of bruising issues.

"There's no merit in keeping material in store and incurring more and more costs if it won't make the grade. Get in and have a look and make sure that they're still okay."

Mr Cunnington said that growers must adopt new technologies to improve performance, particularly with stores dating from the mid 1970s. As a starter, a sub-meter to monitor energy consumption of stores could be installed.

It was also important to consider store temperature. Was it possible to run one degree warmer at 3.5C for processing potatoes or going from 8C to 9.5C for the chip shop market?

"We have to think about the market. For a pre-pack store, using ethylene as a sprout suppressant, there's no point in running at 2.5C because it would be better to run at 3.5C."

He said that growers need to think about a temperature strategy for "pull-down" immediately after harvest, which was hugely costly in energy terms as the crop had to be cooled as quickly as possible. This "pull-down" phase could account

for as much as 25 to 30pc of energy costs.

"I don't feel that the stores are

quite showing the optimal trend at the moment. We have some very efficient processing stores but some of the cold stores have much more to do.

"We're now looking for some champion stores - the best stores," said Mr Cunnington. "Go back to your store and start this process by establishing what your energy costs are."