Expert outlines simple steps to reduce energy use on dairy farms

Dairy farmers should take action or risk paying for electricity they use but is wasted, an expert has warned
Dairy farmers should take action or risk paying for electricity they use but is wasted, an expert has warned

Simple adjustments like correctly setting time clocks on water heaters and lagging pipes can capture big energy cost savings for a dairy farming business, an energy expert has said.

Milk cooling, water heating and vacuum pumps account for the biggest proportion of energy use on a dairy farm and therefore offer the greatest scope for savings, according to energy specialist Chris Brooks.

During a recent Farming Connect webinar, which is an industry initiative by the Welsh government, he urged dairy farmers to take action or risk paying for electricity they use but is wasted.

Basic measures such as using timer switches, lagging hot and cold water pipes and water tanks, replacing sodium floodlights with efficient LEDs and ensuring equipment such as condensers are clean and well-maintained make a big difference.

At an electricity price of £0.37/kWh, the annual cost to an average size dairy farm is now approximately £105/cow. For a 250-cow herd, this adds up to £46,250 a year, up by £26,250 in a single year.

Other sectors, including poultry, have been hit hard too. A 32,000-bird multi-tier layer shed with an annual electricity demand of 2.5kWh/bird was typically paying £0.17/kWh a year ago but, at a £0.40/kWh tariff, costs have increased to £87.67 a day or £32,000 a year.

There are steps all systems can take to reduce electricity use and, as a consequence, costs too, explained Mr Brooks.

He suggested that use of data loggers, used to identify where wastage is occurring and typically carried out over a period of 7-10 days, is a good place to start.

For hot water tanks, he recommends having adequate lagging to prevent heat loss and installing a heat recovery unit – although many farms already have these, they might not be working correctly so that needs checking.

Mr Brooks also advised monitoring the parlour and tank wash exit temperature against the requirements of the dairy chemical being used, to allow for heating water to the lowest possible setting without having a negative impact on milk hygiene.

Only use lights when and where they are needed and at the intensity required, and only cool milk to the required temperature, he said.

Some farms Mr Brooks has assessed are routinely cooling to lower temperatures for no specific reason and are therefore using more electricity than they need to.

“If milk needs to be cooled to 5°C, why cool it to 3.4°C by using half an hour of compressor time to drop the temperature lower than where it needs to be?" he said.

For energy supply contracts, it is beneficial to know when the end date is to allow for early preparation, he added.

And farmers should consider smart metering, as this gives access to a wider range of tariffs which may be more competitive.

“If your electricity meter is not read remotely make sure that you always send actual meter readings to your supplier on a monthly basis to avoid estimated readings that can sometimes be very inaccurate."

Investing in renewable energy is an obvious solution to protect a farm against price volatility and reduce costs, but it is important to consider which option is the best fit for the farm’s demand profile.

For example, many dairy farms invest in solar when a big proportion of their energy use occurs before sunrise. And when their energy need is greatest - when stock are housed in the winter – sunlight is limited.

“On an annual basis, the length of day and prevailing weather means that in the UK, solar PV generation is highest in June and lowest in December and January," said Mr Brooks.

For some dairy farms, it works well – for example, one that milks three times a day when there is high demand through the middle of the day when daily solar generation is highest.

Solar PV could be less beneficial for a robotic milking unit with a consistent 24-hour demand, said Mr Brooks.

For that system, a smaller solar PV system will provide the best benefit together with a two rate or RAG (Red Amber Green) supply tariff, he advised.

Although battery storage is touted as a solution by supply firms, he urged caution. “The technology needs a lot of planning to make sure it works for you.

“The design of any system, including the size of the solar PV and capacity of the batteries, has to be planned very carefully to ensure benefits are realised from the investment in both summer and winter conditions."

Mr Brooks gave the example of a 200-cow dairy farm he visited. It had installed a 50kW solar PV on its cubicle shed with 10kWh of co-located batteries, an investment of £80,000.

“They discovered that the battery storage capacity was totally inadequate and fully discharged within 20 minutes of milking starting," he said.

“Make sure you question thoroughly what you are being told by enthusiastic salespeople."