Saving money with renewable energy
Dairy farmers could slash their input costs by investing in renewables technology, as one farm manager in Devon has discovered. Olivia Cooper reports.
Investing in new technology may not be at the top of many dairy farmers’ priorities right now, but in the long run it could save them thousands of pounds.
Over the past 18 months, Bicton College’s home farm near Budleigh Salterton has reduced its electricity costs by at least £2,000 a year, with further savings already in the pipeline. Although some of the options have been very capital intensive, others are relatively cheap and accessible to all farmers.
Vacuum on demand
“The first thing we did was put in a vacuum-on-demand pump for milking,” says farm manager Paul Redmore.
“The original pump ran at a set speed all the time, which created more vacuum than we needed for milking, so we had enough to power the wash system. The new pump matches the speed to requirements, so it runs on tickover virtually all through milking, and then at full tilt when washing through.”
The pump cost £6,500, but Bicton obtained a 40% grant through the R4F fund in the South West. “It is saving us £1,000 a year in electricity, so although the payback was originally calculated to be five years, it will be closer to four,” says Mr Redmore.
“The other benefit is that it’s really quiet when running, so it’s a nicer working environment and is easier to instruct students in the parlour. It also uses less oil – and we’ve still got the old pump as an emergency backup.”
Heat exchanger
A heat exchanger unit on the ice bank condenser was the next step. “It heats water to 40-45C, which then feeds into the boiler to take it up to 90C for washing out – before that the heat was just being wasted,” says Mr Redmore.
Costing £7,500, the heat exchanger also qualified for a 40% R4F grant, and with electricity savings of £1,000 a year, it should pay for itself within five years.
Last year, Bicton College unveiled its EaRTH Centre, a dedicated training and conferencing centre for renewable energy and sustainable building. It includes a woodchip-fired biomass boiler and a 10kW roof-mounted solar PV array.
Surplus heat
Any surplus electricity produced by the EaRTH Centre is used by the farm, with surplus heat from the boiler soon to be pumped to the dairy in the form of hot water.
“We are also about to buy an electric quad bike,” says Mr Redmore. “At the moment we have a 400cc ATV, which costs £1,500-1,700 a year in petrol. The electric one will cost £150 a year in battery charging – which we can do from the solar PV array. However, the batteries have to be replaced every three years so that has to be written down at £260/year, so our total saving will be at least £1,000 a year – and we will reduce our carbon footprint at the same time.”
Also in the pipeline is a 50kW ground-mounted solar PV array, which has just received planning permission. As well as powering the farm, it will provide electricity to the five classrooms, three offices and other facilities located on the site, cutting the electricity bill in half, to £4,000-6,000/year.
Water pump
“We’re also looking at installing a water pump, which will use the gravitational force of water to extract it from our stream, pump it to a high point and gravity feed back to the water troughs,” says Mr Redmore. “The payback should be under a year through reduced water costs. We already recycle the cooling water from the bulk tank, and at some point we will harvest rainwater from the barn roofs, as we already have a disused underground slurry store where we can store it.”
With costs of production at just 23.6p/litre in the year to August, the extensive, low-cost system is clearly working.
“Last year we produced 10,529 litres of milk a hectare off forage, and with a milk price of 26.68p/litre we had a margin over purchased feed of 22.89p/litre.”
Farm facts
- 166ha farm, predominantly grassland with 22ha maize
- Commercial farm providing 33,000 hours a year of student teaching
- 200 cross-bred cows (Holstein Friesian x Jersey x Ayrshire)
- Extensive grazing system, outdoors year round
- Block calving in February and March
- Yielding 5,440 litres, 65% from forage
- Margin over purchased feed of 22.89p/litre
Savings at Bicton
- Vacuum on demand – £1,000-a-year savings in electricity
- Heat exchanger – £1,000-a-year saving
- Electric quad bike – will save at least £1,000 a year in electricity
- PV array – will cut electricity bills in half
Find out more about renewable energy on dairy farms on our dedicated page