To save £thousands, first you need to measure
Stores that don’t have meters fitted could be frittering away energy costs, warns Adrian Cunnington, head of Sutton Bridge Crop Storage Research (SBCSR).
By using meters to monitor energy use in each individual store, managers can examine where the costs are, and whether any of these costs could be cut without compromising quality, says Adrian.
“We installed meters in our stores two years ago as part of a project undertaken with SBCSR,” says Steve Marshall, store manager at RS Cockerill. “It has made us aware of what we use in-store, but more than that, it helps us improve efficiency.”
Measuring electricity usage has made Steve more aware of costs and his company now avoids running the store half-empty where possible, making important energy savings that can make a difference when profit margins are tight.
“It’s useful to have these figures to hand when you are examining the possibility of making changes in-store or buying new machinery. You know what your machinery costs to run – so you can make useful comparisons before you buy.
“I would wholeheartedly recommend all store managers to invest in having them installed. A new meter costs around £300, but just think how much we spend on other farm machinery, such as a new tractor.”
Store managers with 1,000 tonnes of potatoes for the fresh market could save up to £1,600 a year with more energy-efficient storage, if they know exactly where their costs are.
Adrian was one of the principal researchers of the recently-published energy project Reducing the Energy Cost of Potato Storage, funded by the Potato Council. 36 potato stores, representing a typical cross section of GB stores, were studied by Farm Energy and SBCSR over three years and results collated and analysed.
“The least energy-efficient potato stores use up to three times more energy than the best ones,” he continues. “With a season’s storage costing, on average, between £4 and £8 per tonne in electricity, it is worthwhile monitoring consumption data as even small changes in usage can offer a quick payback on a meter.”
To reinforce this, Adrian recommends levy-payers benchmark the performance of their own stores, using the Potato Council’s ‘energy hub’ at www.potato.org.uk/energy to access reports showing a range of monthly consumption data across different types of store supplying a range of markets.
“Our results have demonstrated that well maintained, well managed older stores can be as efficient as those built in the last few years,” he continues. “Furthermore, in an inefficient store, investing £15,000 to refurbish insulation can be repaid in as little as five years.”
However, it is important not to reduce energy use at any cost. Crop quality must not be compromised, although some energy-saving measures can also help quality by reducing dehydration (moisture is lost in proportion to ventilation time) and, in the case of inverters, by increasing the efficacy of sprout control treatments.
Although the research revealed significant potential to reduce storage energy costs, there were some stores which did not quite perform to expectations. A follow-on trial is examining this area in more detail to measure the effect of a range of other factors contributing to store efficiency, such as air leakage and fridge performance. These results will start to feed through later in the year.