Garry Ducey has just ripped out the 30-year-old 10-unit parlour on his 120ac farm near Ardmore, Co Waterford.

By the time his 80 cows start calving next spring, he will have a new 14-unit setup in place.

The first thing that went in this autumn was the vacuum pump and its attached variable speed drive (VSD) – a combination that has already cut Garry’s milking electricity bills by half.

The parlour’s technician, local Boumatic Gascoigne Melotte agent Allen Treacy, introduced Garry to the technology this autumn when the Sustainable Energy Authority of Ireland (SEAI) and Teagasc were running a pilot grant scheme for VSDs.

They went for what Allen described as the “Rolls Royce” of vacuum pumping systems:

  • A lobe pump, which offers a greater range of operating speeds than more common vane pumps. They chose a Boumatic Airstar 200 model, which can milk up to 24 cows and take in current frequencies of 16Hz to 60Hz.

    The smart meter Garry used to measure energy savings.

    Traditional pumps can typically fluctuate between 35Hz and 50Hz only, said Allen.

  • A variable speed drive inverter, in this case a single-phase input model, which monitors air demand in real time and delivers just the power needed to the pump at any point.

    The variable speed drive inverter delivers just the power needed to the vacuum pump in real time.

    The highest power is only really needed for washing, and this is still available when required, Allen said.

    • The two machines cost a total of €10,500 excluding VAT. The pilot grant covered 50% of expenses associated with the installation of a VSD up to a maximum ceiling of €9,000, so Garry got the maximum grant of €4,500. This leaves him with a €6,000 cost, which represents under 10% of his overall parlour overhaul investment.

    Using a simple electricity meter that clips on to the pump’s power line and costs less than €100, Garry noted his bulk milk collection and measured his electricity usage before and after the new installation.

    This came to 53kWh or €8 per 1,000l beforehand. With the new pump and VSD, this fell to 26kWh or under €4 per 1,000l in real milking conditions. According to an SEAI estimate, this type of investment pays for itself in around 13 years.

    Power savings are not the only reason behind Garry’s choice. “It’s quieter and it’s more environmentally friendly,” he said. Working at lower speeds, the pump doesn’t create as much noise in the parlour and no longer wakes up his mother in the house next door. And the lobe pump does not spurt any oil out the air exhaust.

    Garry and Allen have also installed a smaller VSD to control the milk pump.

    “It pumps milk on demand by tracking the flow in the receiver,” said Allen, resulting in faster cooling and more energy savings. Garry is also looking into a heat exchanger to use the plate cooler to heat water, but at €3,500 this is not a priority. “It’s something you can add in down the road without upsetting things,” he said.

    Allen said he first installed an Airstar VSD more than seven years ago and has seen increased demand with the recent pilot grant scheme.

    He added that retro-fitting the device on an existing traditional vacuum pump also delivered significant savings. He hopes more funding will be available for this in the coming years.

    “More than 50 farmers are participating in the SEAI pilot scheme to test the real-world impact of this energy-efficient technology,” said Jim Gannon, chief executive of the SEAI. “We consider the test, and the partnership with Teagasc, to be a success and look forward to identifying additional ways that we can help our farming community reduce their cost, and reduce their environmental impact.”

    The SEAI Dairy Farm Pilot Scheme is now closed for applications but those interested in participating in a new scheme for 2018 should email business@seai.ie