On Tuesday and Wednesday Heathcote Shearing Contractors were at Phillip and Jan Diprose’s property, “Ochre Arch” shearing merino weaners.
What was unusual about this common event on local farms is that the shearing plants, lights and press were all powered by the recently installed remote solar panel and wind turbine battery based (non-grid-connect) renewable energy power supply set-up.
The farm has never been connected to mains power.
When Fred and Aylmer Bokeyar built the cottage around 1940 (after fire gutted the original house) they used kerosene for both lighting and the refrigeration.
Lindsay and Heather Causer bought the place in 1950 and installed a petrol driven motor and 32 volt generator with batteries for lights and washing machine. The cottage still had a copper, fuel stove and two fire places when Phillip and Jan bought “Ochre Arch” in 2003 from Phillip’s mother Judith.
In late 2006 Phillip and Jan decided to move to the farm from Melbourne to put into practice first hand their learnings in regenerative land management and obtained two quotes to connect mains power.
The cost was prohibitive and installation of a renewable energy system proved the way to go after taking into account the Federal Government subsidy - 50 % of the cost of the renewable energy components.
Central West Solar, based at Orange and owned by Robert Biviano, was the closest approved system installer.
In designing a remote power system the critical steps are estimating power usage requirements and determining ‘days of autonomy’ defined as number of days the system can run assuming normal use with zero no power harvested from solar panels or wind turbines.
On the latter – Phillip and Jan opted for 3 days. All cost effective set-ups need to have a back-up non-renewable energy (e.g. diesel) generator.
On Ochre Arch it proved appropriate to build a new shed for solar panel support, housing of the control system and general storage and use.
The renewable energy arrangement now in place has 15 X 175 watt solar panels making it a 2.6 kilowatt system, a 350 watt wind turbine, 24 X 2 volt zero maintenance gel batteries weighing in total 1.5 tonnes and storing 1200 amp hours of power, solar and wind turbine controllers, a high-tech inverter that converts 48 volts to 240 and vice versa, a 14 kva diesel back-up generator, a modem connection allowing for remote diagnosis of problems and general performance monitoring and a main fuse box.
On installation a bloke from the company that manufacturer the inverters ‘dialled in’ to the system and at one point started the diesel generator from his PC in Melbourne.
The system is fully automated such that, for example, the diesel back-up generator kicks in when the batteries get down to 55 % capacity and also when and if there is a very heavy demand for power such as using a welder.
Diesel use is around 1 litre per hour and in this amount of time it will top up the batteries by about 10 %.
The batteries are expected to last around 15 years and solar panels 25 years.
The wind turbine sits on a 13 metre guy-rope and pole tower.
The shearing shed on Ochre Arch was constructed by Lindsay Causer around 1955 from Normoyle frames. It has a concrete floor as he really only intended using it for grain storage. His decision to set it up as a shearing shed meant that he did not have to pay tax on the construction. The sheep yards were manufactured and installed by Don Hampton some time during the period he and Marie owned the place (1965-77). Curiously the steel posts are recycled steam engine boiler tubes. Roy Kelly was the publican at the Exchange Hotel and owned the farm from 1977-79. He and many hotel patrons constructed the skillion that now forms part of the shed. Graeme Schneider recalls doing the wool classing for Roy for the two years he was the owner. Phillip’s father Bruce bought the farm from Roy as an additional to “Roselea”.
The new power system on Ochre Arch handled the shearing shed demand comfortably. On Tuesday it was overcast all day and used only 20 % of the stored power in the batteries. On Wednesday whilst the sun was shining the energy harvested by the panels exceeded total power demand.
The wind turbine power generation has not been factored into the system supply calculations so everything it produces is a bonus. There are some natural synergies with a remote power system. It takes sunlight to heat the atmosphere so when the ambient temperature is such that air conditioning is required there is sunlight to produce the power. As a general rule the wind is strongest when there is cloud cover and thus the wind turbine fills part of the power generation gap.
As the system is not grid-connected sale of surplus power is not an option. On the other Phillip and Jan should not experience power blackouts.
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