Responding to spindoc of 3 May:
You are indeed a spin doctor for anti-wind power interests, even quoting your guru John Etherington, a retired biologist who has no scientific or engineering credibility in this field. Wind power supplied, not 13% as you claim, but 21% of Danish electricity in 2009, and with the recent new installation is expected to supply about 24% in 2011.

Your claim that ‘over four fifths of this is exported to adjacent countries’ is incorrect. Because wind power has the lowest marginal cost to operate, it gets top priority for use in Denmark. When the marginal cost in the Nordpool electricity market (of which Denmark is a member) rises to a sufficiently high level, Denmark fires up some reserve fossil-fuelled power stations to supply exports. Your myth is busted in detail in the report by Danish energy experts, ‘Danish Wind Power: Export and Cost’, <http://www.ceesa.dk/publications.php>.

Responding to Forrest Gumpp of 3 May:
My answer to your ‘pivotal point’ is no!
4600 megawatts of Australia’s base-load coal-fired power stations are used to heat water, which is supplied to customers at cheap off-peak rates. This is the result of the operational inflexibility of base-load power stations, which cannot be switched off overnight. If cheap off-peak electric hot water prices and hot water systems based on electric resistance heating were both phased out, these unnecessary 4600 MW of coal-fired power stations could be retired. Water would be heated efficiently by solar, gas and, in the minority of cases where neither solar nor gas is available, electric heat pump. The intermediate-load power that is today supplied by these unnecessary coal-fired power stations between dawn and midnight would be replaced by renewable energy with a little peak-load gas turbine back-up.

Mark,

Your comments on nuclear power stations being the largest consumers of water is deliberately misleading.

Nuclear power stations can also be built using air cooling (and use no water) at extra expense and loss of efficiency as any thermal power station, but, because they can be located far from the fuel source, many of them use sea water which currently is not in short supply.

Secondly, the largest consumers of water per kWhr are the geothermal plants which in spite of using air cooling, lose prodigious quantities of water into the fractured granite.

With respect to the liquid salt based thermal storage, again you are being deliberately misleading.

For example, if one considers a solar thermal plant that can generate a peak capacity of 100MW between 9am and 3pm, the capacity factor is simplistically 25%. (6hrs/24hrs) with an average of 25MW.

If you modify the plant using the same solar collectors, and put in a 50MW generator, and salt storage, you can extend the generating time to 9am to 9pm. (assuming no efficiency or thermal losses) This will now have a capacity factor of 50% (12hrs/24hrs) with an average of 25MW.

In this ideal scenario, the salt storage has not added any capacity whatsoever, but has enabled generation during peak periods. However, the difference in the cost of the generator saved is a tiny fraction of the cost of the salt thermal storage, thus increasing the cost per kWhr of the entire system. If the loss of efficiency and heat is factored in, one then reaches the 40c kWhr of the trial plants, which is roughly 4x the cost of nuclear.

Although it is probably decades from being financially viable, it is the single technically viable renewable alternative.

The suggestion that electric cars can be used as an on line buffer for
the grid is I suspect flawed.
Most cars will be charged at off peak rates during the night.
Battery life is longer at slow charging rates, so most will charge at
the lowest rate consistent with getting a full charge in the period.

If it was my car I would not be happy with a discharge happening during the charge time or after it.

I don't think it has ever been tried.

Shadow- few things

Salt water is in no short supply- however unless you apply materials that can withstand salt water to line the cooling channels with (possible, but not so easy), it would become a huge expense (and pollutant) to desalinate it (as the fiasco in NSW demonstrates).

Solar-thermal? A rather pointless power supply actually- PV panels can obtain energy from the exact same power source, but in a direct conversion of energy- and use no other materials (or even moving parts) for energy generation to occur.
Furthermore, they don't even actually need to be run through a centralized power-plant but can be directly applied to households and businesses.

KH,

There are grades of stainless steel produced in vast quantities for chemical plants all the time that can withstand sea water. So much so that this is quite common.

PV is not viable in houses, as the cost is about 40c /kWhr to produce.

A 4kw solar panel can be installed for a total cost without rebates of $19,000 in NSW and the ACT. http://www.australiansunpower.com.au/

My 1.5 kw system averages 7 kwhs of energy per day or a total of 2555 kwhs per year. At price of 12 cents per kwh a 4kw system will give a return on investment of 4.25% and it should last 25 years and return the value of the investment. (the ACT feedin tariff of 50 cents that I have in place means my return on investment is closer to 17%). If you can afford to install solar panels and you get the government rebate and you get a feedin tariff then you get a very good return on investment.

Solar installations have dropped in price significantly over the past two years and we can expect the price to drop by at least 20% per year each time we double installed capacity. It will not be long before solar panels will require no feedin tariffs or rebates to become a very sound investment. Even today without rebates and feedin tariffs they make good sense because the price of mains electricity is going to increase substantially over the next few years.