Measures to increase energy use efficiency on dairy farms

A recent webinar, hosted by AgriSearch, featured discussions around ways to increase energy use efficiency on dairy farms.

Dairy farmers are well aware of the rising cost of energy, which has resulted in a higher cost of production.

In order to mitigate or reduce the rising cost of energy on farms it is important that farmers look at options that will suit their farms.

These options include improving efficiency of energy use and incorporating renewable electricity.

Energy use efficiency

Speaking on the webinar was Dr. John Upton from Teagasc, Moorepark, who spoke about strategies to reduce energy consumption on dairy farms.

Dr. Upton first outlined some research conducted by Teagasc into the area of highest energy demand on farms.

This research determined that: Milk cooling accounted for 31% of energy demand; water heating 23%; milking 20%; other 18%; water pump 8%; and lighting 3%.

Dr. Upton said that due to the introduction of chlorine-free detergents, the demand for hot water has increased, which has likely slightly increased its contribution further.

Dr. Upton outlined that at the current cost of energy, on average, this is costing €12/1,000L of milk sold.

Upton noted that this ranged from €7.50 to €14/1,000L of milk sold.

Energy use efficiency

Dr. Upton stated that one of the key areas farmers should look at is the use of a plate cooler to reduce cooling requirements for milk.

Upton said that over 90% of dairy farms have a plate cooler in use, but that they should ensure they are being used and working correctly.

He said that the goal of a plate cooler is to reduce the milk to within 5° of the incoming water.

For example, if the water is 10°, the aim is to reduce the milk temperature to 15°.

He also stated that it is important to ensure that enough water is going through the plate cooler; the milk-to-water ratio needs to be 1:2.

Used correctly, it will reduce milk cooling energy requirements by up to 40%.

Another option highlighted by Upton that could reduce energy demand on dairy farms was the use of a variable speed vacuum pump.

This reduces the amount of power being used when clusters aren’t attached to cows and increases when they are.

Water heating

Assess to hot water is vital on dairy farms to ensure that milk quality is maintained.

Dr. Upton firstly outlined some of the current costs of heating water on dairy farms – which are in the table below.

He then outlined a number of systems that farmers can use to reduce the demand placed on these energy sources.

One of these was the use of a heat recovery system, which removes heat energy from milk during cooling.

These can be retro fixed to existing bulk tanks.

This energy is then transferred to a tank of water and it can reduce water heating cost by 40-50%.

Dr. Upton also spoke about the use of solar photovoltaic (PV), which generates electricity from the sun.

He noted that there is a big mismatch between supply and demand on farms, which makes it necessary to use some form of energy storage with the farmgate, which Upton notes can be supplied by a simple electrical water heater.

This means that the energy that is produced by the panels that is not being used on the farm can provide the hot water for post-milking washing.

Payback

Dr. Upton also outlined that the payback period for these items and the carbon dioxide (CO2) savings that can be obtained:

• Plate cooler has a payback period of two to three years and has a saving of 2.5t of CO2;
• Variable speed vacuum pump has a payback period of three to seven years and has a saving of 1t of CO2;
• Heat recovery system has a pay back period of three to four years and a saving of 1.6t of CO2;
• Solar PV has a payback period of three to seven years and a saving of 4.6t of CO2.

All of these measures in total have a saving of 9.7t of CO2 for a farm, along with reduced energy requirements.