Agree with last comments Sylvia. I have roof mounted solar panels but I use grid electricity at night. Tas Hydro has a Bass gas fired backup generator when the hydro and the wind farm are underperforming. I don't know what they'll do when gas is short. The southern drying trend affects rainfall in Tasmania as well as the Snowy Mountains so I don't know if repumping is a long term option. The public needs to think about all these problems and not put too much trust in unproven concepts. In fact I don't see any easy solutions at all.

Sylvia,

Your comment that "Solar capacity, whether solar tube, or otherwise, has the problem that it only functions during the day, and works best when there's no cloud, so it also involves some standby capacity, and alternative generation capacity to cover the night-time base load" is not completely accurate.

See, as Terje has wisely provided, enviromissions' web site.

Solar towers work on the basis of temperature (pressure) difference between the top of the tower and the bottom. If there is a temp difference then there is air flow. There is always a temp difference. In fact, the greatest temp difference occurs at the end of the day when the upper air temp is low and the ground temp is high. It provides 24 hour generation with peak delivery at dusk, handily coinciding with peak demand.

I think Fickle Pickle's comment illustrates part of my initial point. The issue for an investor is how big the return, or dividend, will be.

A nice brand-new wind farm was recently opened at Canunda in South Australia. This state of the art system has a capacity of 46MW, and cost $92 million. Actually, the capacity figure is a bit misleading, because that is really its maximum generating capacity when there is enough wind. Its average capacity will be somewhat less. The ratio between the average capacity and the maximum capacity is called the capacity factor. The American Wind Energy Association (who presumably support the idea) says that common capacity factors lie between 25% and 40%. If we're generous, then that means that $92 million has bought an average capacity of 20MW. To return a 5% dividend on investment per year, and returning the capital over 25 years (our supposed lifetime for the windfarm) means that the farm has to earn about $740 per hour. But each hour, on average, the farm only delivers 20MWh, so the electricity has to be sold for $37 per MWh. This doesn't even take into account other capital costs like connecting to the grid, or operating costs (personnel etc). But selling the power for $37 per MWh is already problematic. The investor could do as well by putting the money on deposit in the bank, with no risk.

There's no conspiracy to avoid financing these things. It's just that absent special financial incentives for green generation, or penalties for non-green (which would push the price of power up), the wind farm cannot give a reasonable return on investment.

BTW, look at
http://www.vestas.com/pdf/produkter/AktuelleBrochurer/v90/v90_2/V90_2_UK.pdf

as a type typical wind generator. It requires 10m/s or 36km/h winds to generate full power. That's a fair wind.

Look at

http://www.bom.gov.au/cgi-bin/charts/charts.view.pl?idcode=IDX0102&file=IDX0102.200505141200.gif

The rule is that the closer the isobars (lines) the stronger the wind. I think the whole of the coast of Victoria would have been below 36km/h at that time. I'm sticking by my position that even large scale farms cannot guarantee to deliver adequate power on their own.

I think you have all forgotten reality. Whatever form of power generation you adopt in the future would take quite a few years to bring on line. Thats after you have gone through the beaurucratic stupidity that prevails in every country. I am not an academic and don't have, Dr, phd, wank wank, before or after my name, I am just an ordinary person. But even I can see that the window of opportunity for us to turn around the decline in our environment and society has passed us by and all you do is try to semantically confuse everyone. Wind generation systems placed in Bass strait, would endure many weeks without wind. This goes for all areas that are suitable for wind farms. Sadly all you people can talk about is the economics of energy generation when you should be using you so called academic knowledge to provide solutions that take into account the reality of our energy environment and not the economic illusion. Just remember if you can, that you can have an environment without an economy, but you can't have an economy without a suitable environment. Sadly academics can't fathom that out, they just blindly go on repeating their programmed indoctrinations and attempt to semanticaly confuse us all. You have no answers, just ridiculous meaningless chatter. Even an uneducated norm like me can work it out and arrive at solutions that are meaningful for the people and not just academics or big business profits.
The alchemist

Alchemist if you have a solution you should say what it is. Then consider whether business and the public will accept it, coz that's the real problem. Even some academic 'w*nkers' have argued that in a crisis the normal rules don't apply.

My solution is to place small scale wind and solar generation on every house in rural australia as well as wave and tide generation in coastal communities. These can be placed within current wharfs and jetties. The next step is to repower the cities using the same methods. Not pratical you may say, but by using technologies that have been proven to be inefficient, coal, nuclear and gas, you only increase the problem. Firstly we have to re-arrange how those in the city use energy, as they are the ones that are the biggest waste creators on the planet. Business wouldn't like this because it would put power generation in the hands of the people and reduce their costs, academics and big business would not be able to bleed people constantly of their economic resources. We also have to stop using fossil fuels to power vehicles, the only way to do that is to subsidise the change over to electric and hybrid vehicles now, reducing pollution and energy use. We have to change our transport system to electric light rail everywhere across the country. By using small automatic vehicles, we can have a constant transport system that would be efficient and environmentally sustainable. They could be recharged by using the surplus energy of communites as well as exporting energy to cities and reducing the cost for business. This approach would create lots of long term stable jobs, reduce pollution dramatically, cut the cost of infrastructes upkeep, (roads etc) and put sustainability back where it should be, in all our lives. As an interim, biodiesel plants would need to be set up and crops planted to produce biodiesel. Biodiesel produces less harmfull by-products that fossil fuels. Again this would stimulate the economy giving farmers a viable and long term future market. It would also stabilise costs and allow industry to plan for its fuel consumption knowing that prices would remain quite static for the long term. Not enough room to give all the details here, but thats just a start.
The Alchemist