Analyse energy use to cut dairy costs

How do you get a grip on where energy is being used in your dairy business? DairyCo can give you a guide.

Despite all the action in the parlour, 33% of electricity use on a typical dairy farm is for heating water for washing, 33% for cooling milk and the rest for running the parlour, lights and other equipment.

This simple three-way split should allow producers to focus attention on where to cut energy use and, therefore, costs, says DairyCo’s energy guru Kate Cross. “It’s relatively simple. Get your electricity bills for the past 12 months, add up the units used and divide by the number of cows in the herd,” she says.

Typically, energy use should be between 300-500kwh a cow. “That’s a wide band, but don’t forget there’s a huge diversity in parlours being operated and equipment used,” she adds.

Most dairy farms will be tied in to a contract with an energy supplier. But it is worth checking what you’re paying and whether the contract is still current. “Farm businesses can get a nasty shock when the contract runs out and the energy supplier puts the business on to a standard tariff.

“Costs can soon mount and you could be accumulating considerable costs unknowingly,” she warns. It is worth comparing tariffs – a lot easier if you have access to the internet to check prices on-line. Energy suppliers are in a competitive market, so renegotiation of contracts is not out of the question.

“Also, most contracts will have a ‘white meter’ or period within any day when the user pays a lower rate for energy just like the old Economy 7 tariff for domestic properties.

“Check if you have it and when the time is set. Aim to get much of the high-energy use, such as heating hot water for parlour washing, done in this time you can save hundreds a year.”

According to industry figures it takes 21kwh or units of electric energy to heat a 225 litres (50gal) hot water cylinder to 85C. “That’s 7665 units a year and at 8p/unit (some producers may be paying as much as 11-12p/unit), it costs £613. That rises to £958 a year when you heat a tank twice daily (one on low tariff and one tank full at standard day rate).

“But you can cut that to £710 by having two 50gal tanks heated in the low tariff period and reheating the second tank before use later in the day. It costs less to reheat warm water,” she adds.

Other simple steps include checking tanks are in good order, sufficient in capacity and properly lagged. Also, be sure the timer is not only properly set to coincide with a low-tariff energy use period, but is accurate, too.

Milk cooling is the other key area for cost. Farms on boreholes could make use of the lower temperature of ground water than mains supply. “For example, running borehole water through the plate cooler before entering the hot water tank will remove and make use of some residual heat taken from the milk itself.

“It is important to check what savings may be achieved before investing capital. Producers can download an Energy Efficiency Guide from our website – www.dairyco.org.uk – for free. We will also talk producers through possible changes to cut energy use.”

Other simple checks can cut costs. Are refrigeration unit fans clear of debris such as leaves and dog hair? “Also, check fans have good airflow. If you’ve altered building layout since they were installed can they still get adequate airflow?”

The final third of energy use will be for heaters, lighting and equipment such as backing gates or scrappers. “Lighting is a key area. It costs £65 a year to run a 500W halogen-type lamp for eight hours daily. Multiply that by the number of lamps and it can be costly.

“By the same token a sodium lamp costs just £9.20 a year, although bulb costs are typically three times higher,” she says.

“The thing to remember is that energy use can be a hidden cost until the bill lands on the doormat. If you were locked into a contract price two years ago you could be on a good deal compared with today.”