Clean and green ... or nuclear?

If we were to accept the basic outline of the SDD plan, we'd need to phase out the use of gas over a period of several decades. The most promising candidates are solar thermal power with storage (e.g. in molten salts) and geothermal "hot rocks". Solar with storage is about twice as expensive as other low carbon electricity sources. It will certainly become cheaper, but we don't know how much cheaper. For geothermal hot rocks, a great deal of exploration and development is underway in Australia, but we've yet to see large scale geothermal electricity generation.

CSIRO scientist Dr John Wright has proposed a plan in which renewables generate over three-quarters of Australia' electricity by 2050: wind and geothermal both produce 19% of electricity demand, solar thermal 18%, solar photovoltaics 13%, bioenergy 5%, and hydro continues to provide a small percentage.

Siemens Ltd., a company with extensive involvement in the energy sector, has mapped out an energy plan for Australia in which the contribution of fossil fuels to electricity generation falls from 93% to around 10% by mid-century, with the remainder generated by a mix of renewables consisting mainly of solar (35%), wind (18%), and geothermal (17%).

Australian engineer Peter Seligman has proposed an energy supply system for Australia based largely on geothermal, wind and solar power. To ensure reliable electricity supply, Dr Seligman proposes the construction of a large "pumped hydro" energy storage system. When electricity is in short supply (e.g. calm, cloudy days), water from a very large dam is run downhill through turbines to generate electricity. At other times, water is pumped up hill to replenish the dam.

In a 2010 paper, provocatively titled "The Base Load Fallacy and other Fallacies disseminated by Renewable Energy Deniers", Dr Diesendorf writes: "Some sustainable energy sources and measures are at least as reliable as coal power. These include demand reduction by means of energy efficiency, energy conservation and solar hot water, and renewable electricity supply by hydro with large dams, bioenergy, solar thermal power with thermal storage and geothermal power. They can all be used to reduce the demand for base-load coal without reducing the reliability of the generating system."

Some other clean energy plans for Australia are those by Dr Diesendorf, Greenpeace and Beyond Zero Emissions.

One final question: why the objection to nuclear power? The key problem is its repeatedly demonstrated connection to the proliferation of Weapons of Mass Destruction. Former US Vice President Al Gore has summed up the dilemma: "For eight years in the White House, every weapons-proliferation problem we dealt with was connected to a civilian reactor program. And if we ever got to the point where we wanted to use nuclear reactors to back out a lot of coal … then we'd have to put them in so many places we'd run that proliferation risk right off the reasonability scale."

The connections between nuclear power and weapons have a precedent in Australia. Prime minister John Gorton had military ambitions for the power reactor he pushed to have constructed in the late 1960s at Jervis Bay on the NSW south coast. He admitted 30 years later: "We were interested in this thing because it could provide electricity to everybody and it could, if you decided later on, it could make an atomic bomb."