>Maybe you should look into the economics of solar energy a little bit
>... let me give you a hint: global solar is not being held back by lack
>of investment. All of the interesting proposals for using solar presume
>the economics come from not having to provide the power in other ways --
>and since Africa doesn't use that much today, you're talking about
>having to foot the entire bill. Solar only makes (some) sense in places
>like California and Las Vegas where you can say: if we don't do solar,
>we have to do something else, which is much more expensive and painful.
Solar isn't the only fish in the sea and photo-voltaic isn't even the only way to harness solar. But economics is a problem to be solved. As the article below mentions, one big problem is that it is difficult for these alternatives to compete with coal burning. Having realised that burning coal is a false economy, because it doesn't take account of the environmental cost, we need to change the economics.
Sorry about over-posting, but I'm sure Doug would agree that on this issue, on which depends the very survival of the planetary eco-sphere we can set aside minor technicalities. In fact I would advocate this issue be exempted from the daily limit.
Bill Bartlett Bracknell Tas
http://www.smh.com.au/articles/2007/04/11/1175971183212.html
Scientists get hot rocks off over green nuclear power
John Garnaut April 12, 2007
PEOPLE could be using "green nuclear" energy in their homes within three years as entrepreneurs rush to produce zero-emissions electricity.
Geodynamics Ltd told the Australian Stock Exchange yesterday it had sped up plans to harness the heat generated by natural nuclear activity deep beneath the central Australian desert.
The company plans to pipe high-pressure hot water from the granite bedrock four kilometres beneath the Queensland-South Australia border, where the slow decay of potassium, thorium and uranium generates temperatures as high as 300 degrees.
"The granite is hot because of the natural nuclear activity in there - it's green nuclear," said the company's chief executive, Adrian Williams.
Dr Williams expects the company to send electricity to the national power grid by 2010 and later directly to western Sydney. By 2015, it could produce as much electricity as the Snowy Mountains hydro scheme.
Some scientists say hot-rocks technology could soon deliver huge volumes of economically viable power, thanks to the continent having the hottest and most geologically favourable granite deposits on earth.
"There's enough energy to run the country for thousands of years," said Prame Chopra, a scientist who sits on the Geodynamics board.
According to a conservative estimate by the Centre for International Economics, Australia has enough geothermal energy to meet electricity consumption for 450 years.
The industry has strong backing in Canberra. "I've been a fan for a long time," the Minister for Industry, Ian Macfarlane, told the Herald. "The theory is very sound. What they've got to do now is prove that it works."
The granite in South Australia's Cooper basin contains "fractures" that hold super-hot, high-pressure water. It could power a steam turbine then recyle water back into the bedrock for reheating.
The hotter the water, the more efficiently it can be converted into electricity.
Australia is home to all of the world's six listed hot fractured rock geothermal energy companies. One, Petratherm, recently signed a memorandum of understanding to supply geothermal electricity to South Australia's Beverley uranium mine by late 2009.
Torrens Energy, which listed on the stock exchange three weeks ago, is exploring hot sites near Adelaide.
The greatest impediment to the renewable energy industry is that the nation's electricity is among the cheapest in the world, thanks to huge deposits of high-grade coal.
But geothermal energy is expected to be economically viable after a moderate cost is imposed on greenhouse gas emissions.
Geodynamic, assisted by $11.8 million in federal grants, said it would produce one megawatt of electricity for about $45 an hour - compared with coal power of about $35.
The Prime Minister's taskforce on nuclear energy estimated the cost of nuclear energy at $40-$65, "clean coal" at $50-$100 and photovoltaic solar energy as high as $120.