Greig, my argument is not about subsidizing renewables (although that would be a good thing in my opinion if only to kick start the industry). My argument is about costing in externalities and about NOT subsidizing polluting industries.

We are never going to see eye to eye on these things, our opinions differ on what the ultimate costs of continuing as we are will be versus those of addressing the issues. Also if the costs of encouraging renewables, discouraging increased fertility rates, reducing immigration and dampening excessive consumption prove too much we can always take a step or two backwards.

As far as nuclear energy is concerned I have searched the internet and from what I have read can only conclude that the industry is heavily subsidized. One source claims that over the past 50 years the US industry has been subsidized to the tune of $145 billion (renewables = $5 billion). The industry in the UK has also been heavily subsidized. The 5% levy in the US that you referred to in an earlier post was, from what I can make out, only for some particular decontamination and decommissioning costs and amounts in total to only $2.6 billion.

Forgetting renewables for the moment and going back to subsidies; I would be happy if they were removed, my electric bill went up but my taxes went down to compensate. And exactly how destitute are the industries that benefit from these subsidies I wonder? Are there not perhaps more worthy, say import replacement industries, to whom we can dole out these funds? Should we not rather be protecting selected secondary industries against imports through duties (forgetting GATT for the moment) as opposed to protecting selected primary product exports through subsidies? Are we backing winners by subsidizing coal?

Tom Quirk writes:

"It is difficult to imagine any carbon free technology readily deployable and able to provide [6,000MW of additional deliverable power by 2020] except for nuclear power and wind. Since the government will not consider nuclear power, wind power is the technology of choice."

At this point Tom bases his article on an incorrect premise, that of it being difficult to imagine any readily deployable carbon-free technology capable of delivering an additional 6,000Mw of electric power by 2020. Such has already been proven in concept. The concept is that of using the temperature inversion obtainable in concentrated brines in solar ponds to power conventional organic Rankine cycle engines (familiar to most as refrigeration machinery) in turn driving conventional generating plant.

Solar ponds are acknowledged as being the most cost-effective collectors of solar energy. There is still scaling-up to be done before reliable costings for electricity, ex pondage, can be offered. I wont address this issue in this post. It is complicated because solar ponds in many situations offer economies with respect to transmission costs and infrastructure, which are not necessarily being taken into account in some comparisons being made. I shall offer some numbers with respect to the physical resources required to meet this energy target from solar ponds.

Experience from the Pyramid Hill, Victoria, solar pond indicates around-the-clock generation of 60 Kw of electricity 365 days per year from a pond one third of a hectare in area. See: http://www.enersalt.com.au/Local%20Publish/html/cheap_heat__.html

There exists the possibility to scale the generation capacity installed in conjunction with solar ponds so as to permit greater output per hectare at peak demand times, provided a corresponding reduction in output occurs at off-peak times. Such amplification of generating capacity would seem relatively easy to progressively achieve, given the modularity of organic Rankine cycle engine/generator units, perhaps made in Ford's subsidised factories?

5.5 Ha of pondage would be required per Mw generated 24/7, 33,000 Ha for 6,000Mw.

I would like to interrupt my line of argument briefly for a salute to this question, worthy in a different context of leading to an award of the Geddes Gavel, that was posted by Ludwig, Thursday, 19 February 2009 1:51:33 PM , earlier in this thread:

"Can you tell us what the projected energy demand in 2020 might be if our population remains constant and we achieve something like a 20% per capita reduction in demand?"

To the best of my knowledge, it sadly remains unanswered, be it here or elsewhere.

Returning to the further exposition of solar pondage energy collection and storage as evidence for the claim that it is an incorrect premise upon which much of the article has been based, I would like to illustrate the scope for solar pondage alone to achieve, indeed exceed, the claimed 20/20 target of 6,000Mw of renewable generating capacity.

It has already been claimed that 33,000 Ha of pondage would be required to enable the generation, using organic Rankine cycle engines, of 6,000 Mw of base load 24/7. Solar ponds store enough heat such that they can cope with extended periods of cloudy weather, so the intermittency of generated output, or the complex and expensive technology otherwise required to overcome this intermittency, is not a feature of this method of collection of solar energy. Solar ponds could just as easily be managed as a peaking supply of electricity, simply by deploying more ORC engine driven generators than the ponds could sustain 24/7, such that, for example, only half the pond area could supply 6,000 Mw for 12 hours out of 24, 365 days per year.

A very flexible system, and capable of very quick response to peaking requirements.

Notionally, 165,000 Ha of pondage could provide the entire projected requirement for electricity for 2020 of 30,000 Mw. The area of the salt lake, Lake Torrens, in South Australia, is 593,200 Ha, just by way of comparison. I simply mention it because it is not all that far from the sea.

Forrest,

To get an idea of the "magnitude" of the problem ABARE in 1999 estimated that Australia would need the equivalent of about 180GW of installed capacity generating capacity by 2016. That is, all the energy needed to support our current lifestyle. This includes heating, transport, industry, agriculture etc.

The worst case to reduce net emissions to zero is given by assuming all energy is supplied by electricity. To get 180GW of installed capacity we will need to invest about $300 billion - give or take a 100 billion.

To put this in context. Australian borrow about $22 billion each month to purchase houses. Most of those are for "old houses" so a $300 billion dollar investment over 10 years is achievable. All we need to do is to divert a bit over one months housing loans per year to renewables.

Given enough investment solar ponds could become part of the solution.

[Forrest] “Experience from the Pyramid Hill, Victoria, solar pond indicates around-the-clock generation of 60 Kw of electricity 365 days per year from a pond one third of a hectare in area”

Incorrect. The plants produces 60kW OF HEAT on average. It does not produce electricity. If it was converted to electricity, then heat and Carnot efficiency losses would reduce the output to around 20kW. Amortisation of the generator capital costs plus O&M on the generators would increase the price of power to around 7-8 cents/kWh … not bad only 40% more expensive than what you pay now for grid electricity.

But what about transmission systems? At $2M/km to the remote locations where these ponds are sited, that could add considerably to the costs.

Also, when the weather is cloudy, the ponds do not heat up much. Certainly there is latent heat that will result in continuous output, but the amount of power produced reduces significantly. After a 2-3 days of cloudy weather the output reduces to a trickle. There is no magic here, solar ponds suffer intermittency just like other renewable technologies, and it is the major limitation of renewable energy. Idle backup generation capacity has to be there to handle periods of inclement weather, and that is very, very expensive. It adds 50-80% to the price of supplemental electricity produced.

I would estimate that solar ponds with the necessary backup generation capacity would be able to sell electricity on the market at around 10-15 c/kWh. This is 2-3 times the current price. It is slighty more than the price of wind power, but less than the price of solar thermal and photovoltaic. So for small scale implementation, solar ponds have some merit, but will always need to be subsidised heavily against other lower cost solutions like gas and nuclear.

[Forrest] “Solar ponds could just as easily be managed as a peaking supply of electricity, simply by deploying more ORC engine driven generators than the ponds could sustain 24/7, such that, for example, only half the pond area could supply 6,000 Mw for 12 hours out of 24, 365 days per year.”

This is ridiculous. The proposal is to place half of the generating capacity on idle stand-by for use only for peak power. The capital outlay for the idle generators would nearly double the price of electricity for the whole plant. And also, more importantly, after a few cloudy days the output for the peak load would be unavailable, so would have to come from elsewhere. The solar pond concept is definitely not suitable for peak load supply.

Finally, the obvious flaw in the concept is the need for a continuous supply of water to refresh the ponds. This would require pumping seawater through pipes over a large distance. Besides the huge cost of installing the piping (which adds further to the price of the electricity) , this will consume enormous amounts of energy too, possibly more energy that the plant can output.

In summary, solar ponds can be a small part of the supplemental supply of electricity to the grid, in favourable locations. It is too expensive and flawed conceptually to be deployed at a large scale.