A DAIRY farming partnership is targetting potential cost savings of more than £6,000 annually by taking steps to make the farm’s three-times-a-day milking system more energy efficient.

The Thomas family produce four million litres of milk a year from a 400-cow high yielding Holstein herd at Plas Farm, a Farming Connect Demonstration Farm at Bancyfelin, near Carmarthen.

Cows are milked in a 40:40 parlour. The farm’s annual energy consumption is 211,187 kWh and the combined cost of cooling milk and running three water heaters is £11,966 a year.

The Thomas’s are keen to reduce this cost so they commissioned the Farm Energy Centre to explore options to make the business more energy efficient.

“Energy renewables and environment sustainability had been a focus we were keen to pursue since we embarked upon the Farming Connect project two years ago. It was an avenue we wished to explore and consult via the project objectives,’’ says Lloyd Thomas, who farms with his parents, Neville and Margaret, and wife, Laura.

FEC consultant Jon Swain calculated that the business could potentially save 26.8% on its total energy consumption by upgrading its ice bank bulk tank and plate heat exchanger, installing a heat recovery unit to cool milk and heat water and investing in a variable speed drive to reduce vacuum pumping.

The cost of cooling milk could potentially be reduced by £4,354 and water heating by £1,793, he says. “Improving the efficiency of the milk cooling and water heating systems is necessary to maintain the viability of the business whilst also continuing the programme of business improvement that the Thomas family are keen to achieve,’’ says Mr Swain.

Currently, a combination of mains water and iced water from the ice builder pre-cools the milk via a two-stage plate cooler.

Compressors operate for around 12 hours a day and are underspecified for their current demand. “This results in a considerable increase in the waste heat being expelled into the air and ultimately increased running costs,’’ Mr Swain explains.

Plas Farm consumes 58,719 kWh a year to cool milk. This costs £6,533, the equivalent of 1.96 kWh or 21.8p for every 100 litres of milk cooled. On most farms it is possible to cool milk for less than 10p per 100 litres, according to Mr Swain.

He says the current ice bank bulk tank is an inefficient method for cooling milk because it relies on a two-stage thermal process. If the Thomas’ upgraded their bulk tank, the capital outlay would be £32,000. With estimated electricity savings of £4,354 a year, the payback period would be 7.3 years.

Mr Swain recommends farmers only use an ice bank bulk tank when they have a specific need to cool milk within a time period that can’t be achieved by an optimised plate heat exchanger and mains water. This could be the case if bactoscan readings are high. These tanks are also appropriate when there isn’t sufficient power from the electricity supply to operate the compressors in a DX-type tank and other milking equipment.

Mr Swain says an economy 7 controller should normally be fitted to an ice bank bulk tank but when compressors operate for longer than the seven hour low rate electricity period any benefit is substantially reduced.

He also recommends installing a water overrun solenoid, set to 20 seconds, to allow the plates to be cooled before milk flows through the cooler.

Mr Swain advises cleaning compressors regularly to avoid debris building up on the condensers and getting them compressors serviced annually.

Plas Farm has three water heaters for washing the parlour and bulk tank and for calf feeding. With a combined energy need of 55,732 kWh, they cost £5,433 a year to run. Mr Swain says timers should be used on tank wash water heaters to take advantage of low rate periods.

For the Thomas’s, the recommendations represent an “attractive and substantial saving projection.”

“We are now planning to ascertain several quotations to move forward with our development plan, creating and promoting an environmentally sustainable and financially beneficial future,’’ says Lloyd Thomas.

As well as reducing energy usage, the Thomas’s are keen to generate their own power. They are exploring the options of either investing in a 100kW wind turbine or a 10kW solar PV system but a downside is that a three-phase electricity supply costing around £110,000 would need to be installed.

Although the turbine would generate more income that a solar system, the cost and planning challenges would be greater, says Mr Swain. “At £100,000, the capital cost of a turbine is far greater and it is likely that there will be a more complicated planning process associated with it than with a solar PV system.’’