The Land
Thursday 14/12/2006 Page: 33
By Alan Dick
FOR anybody building or renovating a home in a remote area, solar, wind or even water power could be options for supplying electricity. Apart from being environmentally friendly, they can also be cost effective, given It can cost a small fortune to connect to a power grid, if available.
According to specialists in the field, solar (photo-voltaic cells) and wind are increasingly being used in combination in remote areas.
A combined solar and wind system would include a bank of batteries, a regulator to smooth out the flow of power from the highly fluctuating sources and' perhaps an inverter to convert the current from DC to AC to suit household appliances.
But generally, a back-up power source, such as a diesel generator, will also be required to cover periods when wind or sunlight are low or if the farmer is using power tools or other devices that are heavy electricity users.
Anybody building a new dwelling also has the option of designing their house for energy efficiency to reduce the need for heating and air-conditioning, and tips on this and renewable power sources generally can be found on the website of the Australian Greenhouse Office (AGO), www.greenhouse.gov.au.
According to the AGO, a remote area power system for an energy efficient house can cost anything from $15,000 to $50,000 but it points out connecting to the grid may cost $10,000 per kilometre of power lines.
However, photo-voltaic cells can attract a rebate of up to $4000 for a residential system. The rebate scheme runs to June 2007 and will be reviewed in the Federal Government's 2007-08 budget.
According to James Walker, technical head of Victorian-based renewable power supplier, Energy Matters Australia, the average household uses about 12 kilowatts of power a day.
"But people in remote areas are a bit more energy conscious so they probably use about five kilowatts," Mr Walker said.
He said there had been no significant changes in solar panels for several years, although newer wind turbine designs were quieter than early models. Mr Walker said wind turbines performed best away from turbulence and a household size unit would probably need a tower about 18 metres tall and to be sited so the blades were above the tallest nearby trees.
He said commercially available solar panels were about 13 to 14 per cent efficient in converting sunlight to electricity. "The ones used on space stations are about 30pc efficient, but their cost is prohibitive," he said.
Director of the University of NSW's Photo-Voltaic Centre of Excellence, Professor Stuart Wenham, said a big breakthrough in solar panel efficiency was at least 10 to 20 years away.
But the good news for people who might baulk at the potential cost of a solar-wind combination was Professor Wenham's tip that the cost of panels would decline at the rate of 10 to 20pc a year as manufacturers use cheaper forms of silicon and introduce other technical improvements.
Associate Professor David Wood of Newcastle University's Wind Energy Group said his group was one of only a small number of outfits researching wind turbines in Australia. Their work was aimed mainly at blade design to reduce noise and ensure they started rotating quickly when the wind blew.
Research was also being done on controllers to ensure generators produced the optimum power from the prevailing wind speed and to slow blades down when the wind reached 35 to 40km/hour, he said.
A micro hydro system is the third option but its use is mainly limited to a relatively small area where a constantly flowing stream is available, although there are designs for both fast and slow moving streams.
In some situations, the AGO warns, it may be illegal to interfere with a water course without prior approval and stipulates the environment should not be damaged during installation.
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