Matter of facts in green power play

Sydney Morning Herald
Tuesday 1/5/2007 Page: 12

John Howard says renewable energy can't meet Australia's electricity needs but scientists and other experts disagree.
The claim by the Prime Minister, John Howard, that only coal or nuclear energy can meet the nation's power needs has been condemned as "an outrageous furphy". Speaking at the weekend, Howard said: "There are only two ways that you can run power stations, generate base-load power in this country. You can do it on fossil fuel or... with nuclear power."

But advocates of renewable energy say the Prime Minister is wrong and that wind energy and bioenergy - the burning of waste from agricultural crops - could meet half Australia's electricity demand within 40 years. If all forms of promising renewable energy sources, including solar and geothermal power, were developed, all Australia's electricity demand could be met within 50 years.

Mark Diesendorf, from the University of New South Wales's Institute of Environmental Studies, says renewable energy experts "should be screaming from the rooftops" over Howard's comments. Ric Brazzale, the executive director of the Australian Business Council for Sustainable Energy, describes Howard's remarks as "frustrating".

Diesendorf says no single renewable energy source offers the solution. However, a mix of different technologies, combined with curbs on energy waste, would work. He estimates that because of wind fluctuations at any particular site, a wind farm with 1300 turbines, each generating up to two megawatts - a total of 2600 megawatts - would reliably replace a 1000 megawatt coalfired plant.

"Although a single wind turbine is indeed intermittent," Diesendorf says, "this is generally not true of a system of several wind farms, separated by several hundred kilometres and experiencing different wind regimes." Wind power could meet 20 per cent of Australia's base-load demand by 2040. Another 30 per cent could be met by a network of small generators burning agricultural leftovers from sugar and wheat crops, and plantation forests.

"We could be 100 per cent renewable by the middle of the century" if other technologies, such as solar thermal and geothermal were also pursued, Diesendorf says. While using batteries to store electricity generated by solar cells remains expensive, solar energy could heat water, rocks or even salt during the day. The heat could be used at night to drive turbines. Geothermal technology, in which turbines are driven by water pumped through naturally hot rocks under the ground, also offered "a huge potential".

Diesendorf estimates that while three-quarters of Australian homes could use solar hot water systems, only 5 per cent have them. Peak afternoon energy demand for air-conditioners could be slashed by encouraging people to install solar panels facing the north-west. "What we cant do," he says,"is allow demand to double and redouble every few years. There is a huge amount of energy waste." Insulation and highly efficient electric motors could make significant cuts in demand.

Brazzale, who represents 300 companies with investments or interest in renewable power, estimates 17 per cent of South Australia's power will be wind-generated by the end of next year. "Why can't the rest of us do it?" he asks, calling for a national renewable energy target of 20 per cent by 2020 - more than double Australia's current capacity. Photovoltaic solar panels would have "no problem" eventually meeting 30 per cent of national demand.