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Chockstone Forum - General Discussion

General Climbing Discussion

 Page 7 of 7. Messages 1 to 20 | 21 to 40 | 41 to 60 | 61 to 80 | 81 to 100 | 101 to 120 | 121 to 128
Author
No More Overseas Travel? - Running out of oil?

anthonyk
12/11/2007
2:03:47 PM
On 9/11/2007 evanbb wrote:
>>i don't know where those figures come from but i'd say they're pretty
>>selective
>Oh yeah, they're totally selective. How else can I win the argument? They're
>actually the only figures I've ever heard, I liked them, so I've stuck
>with it ever since.

i don't think you're the one being selective, but i think they're dubious numbers, perhaps best to pass on a source as well.

regarding concrete, its really important if people want to discuss these things to give a level playing field for any comparison. there's good sides and bad sides of everything but its completely pointless trying to emphasise the bad sides of something if you're not going to apply the same scrutiny to the things you support, then its no longer analysis, its more like propaganda.

the numbers i quoted before about co2 output per kWh include start-up costs like building the plants, which includes making concrete. it doesn't say it explicitly there, if you want another source have a look around, i came across another study here, the numbers for materials use are quite old but still relevant for ball-park figures:

Material quantities for construction of selected electricity generation technologies circa 1983.
(Thousands of tonnes per EJ / year)

Generation Technology Steel Concrete Other Metals
Coal - Electric 1500 5500 30
Coal - Synfuel 600 * 30
CANDU 900Mwe (1995) 1600 14000 *
LWR 2500 15000 125
CANDU 600Mwe (1995) 1400 18000 *
Solar - Photo 20000 210000 30000 12000 1800
Hydro 3500 60000 200
Wind 8000 35000 1000
Biomass 4500 12000 *

(the CANDU figures are nuclear plants, as is LWR (light water reactor))

according to this the quantities of concrete required for solar for the same energy output is vastly greater than for nuclear. if you think the numbers for this are wrong you're welcome to find another one.

in general materials costs are much worse for what you would call renewable technologies, because they are much lower power so you have to build so many more plants to generate the same output. of course if you put panels on existing infrastructure there's probably some amount of materials costs savings, but in general there are very significant materials and manufacturing costs for all renewables. i'm not overly pro-nuclear, but it has to be argued on the right grounds.

On 9/11/2007 GravityHound wrote:
>coming from the ANSTO (Aus Nuclear Science and Tech Organiosation) chief
>I would say these figures are pretty selective as well.

ANSTO is a scientific organisation, its not political and its not commercial. Personally i'd trust scientists to give reliable numbers more than i'd trust politicians or environmentalists.


On 10/11/2007 Wendy wrote:
>I wasn't talking about individuals buying solar panels - which I agree
>is still pretty expensive for your average household unfortuneately, but
>the government putting panels on houses for people. ie, instead of them
>investing 2 billion in a nuclear plant or however much it is for new coal
>plants, or for geosequestration, use that money to put in grid connect
>systems on the houses of anyone who's willing and well situated for it.

regardless of who pays for it, the numbers still say that other options are more cost effective in reducing CO2 per dollar than putting solar panels on roofs. i think eventually a solar solution is the best option, but its just not practical large scale at the moment.
uwhp510
12/11/2007
2:18:33 PM
On 12/11/2007 anthonyk wrote:

>regardless of who pays for it, the numbers still say that other options
>are more cost effective in reducing CO2 per dollar than putting solar panels
>on roofs. i think eventually a solar solution is the best option, but
>its just not practical large scale at the moment.

Why not?

http://www.abc.net.au/news/stories/2007/08/01/1994041.htm



evanbb
12/11/2007
2:23:17 PM
>Material quantities for construction of selected electricity generation
>technologies circa 1983.

Do you reckon circa 1983 means those figures were generated in 1983? We've come a long way since then, and I would think that a lot of those have changed since then. But note I'm not rejecting them because of this, just noting that there will be variability there.

I do think that this is an odd set of figures to give. How does solar use so much concrete? It states in the text that these numbers "indicate a very wide variation in quantities of materials to construct power plants of equal energy generating capacity", and so discounts the decentralised solar option. Note also that this paper was presented at "19th Annual Conference, Canadian Nuclear Society", and may not count transport and mining of uranium, and disposal of waste (which is enormous).

Anyway, I'll see if I can find better figures, from a more objective party. If one exists any more, seems everyone's got their own barrow to push these days. I count myself among them.

Dom
12/11/2007
2:25:53 PM
On 12/11/2007 anthonyk wrote:
>regardless of who pays for it, the numbers still say that other options
>are more cost effective in reducing CO2 per dollar than putting solar panels
>on roofs. i think eventually a solar solution is the best option, but
>its just not practical large scale at the moment.

Thatís because Australian's can't sell their PV Power back to the grid at spot prices. We get a flat amount per KWh we generate just like we pay a flat amount per KWh. If we copied Germany's model Australian households fitted with solar arrays would be getting money back from the retailers when they sell their excess electricity back at the prevailing market price.

Right now the eastern states (+ SA) have a price cap of $10,000 per MWh so if you installed 1MW of capacity from solar sources on top of your roof it is highly probable that, under the Germany system, you would get some large checks after summer. But then there are always the vested interests of the generators to consider... if everyone had a solar array why would we need a La Trobe valley?
lacto
12/11/2007
3:31:36 PM
the retailers arent interested in you actually returning power to the grid , they only want you to install "x" kw capacity for which they can claim on the rebates but when you ask about setting up an array to track the sun they claim it isnt worth it as you'll ONLY get another 25 to 35 % more output and it would be better to put in more panels as it is too expensive to track. A 5kw array is quoted at around $55,000 so if 25% more you could spend $14000 to track and be ahead . Personally i believe i can set up a tracker for a few thousand . Still playing around with figures before i commit to such an outlay but I'm going ahead with solar preheat or hot water as currently require 1200 to 1600 litres per day at 90 + degrees and solar should provide nearly all of that 70% of the time and about 50 % of the energy the rest of the time. Pay back on the hot water is of the order of 4 to 5 years where as electric is a rate of return of 2.5% p.a. at present though the capital cost is depreciable over time as well .A carbon tax will certainly make the economics of solar much better . Also where we are around 15% of power is lost in transmission to us (so I'm told) so pwer back into the grid will have minimal losses to get to another nearby user.

evanbb
12/11/2007
3:33:09 PM
I've done a bit more looking into it and found this paper to be very useful:

http://www.uic.com.au/nip57.htm

On average (with big variance) nuclear and wind are about the same energy payback (which surprises me a lot), but I guess nuke gets there by making huge power numbers. Solar not so good. Interesting stuff.

But as I've said earlier there's little to be gained by levelling the playing field between nuclear and wind/solar. You're comparing passive technology with a controlled nuclear explosion that generates the most toxic substance known to man.

Also note, that I only realy believe that nuclear isn't an option for Australia. other countries (the US, France) will probably be better off with more nuclear/less coal. Establishing a nuclear industry from scratch in Australia is full of risks (enviro and economic) and regarded as a bad idea outside Australia (my main source here is the head of the chinese Nuclear Board).

GravityHound
12/11/2007
4:26:58 PM
On 12/11/2007 anthonyk wrote:
>ANSTO is a scientific organisation, its not political and its not commercial.
> Personally i'd trust scientists to give reliable numbers more than i'd
>trust politicians or environmentalists.
>
trust scientists to give reliable numbers - ha! scientists may be philosophically objective but in reality, subjectivity rules. i should know - i am a scientist. an agricultural ecologist. a brief example. ask me about GM crops and i'll rant and rave basically about the potential damage they might cause. ask an agricultural ecologist employed by Monsanto about GM crops and he will tell you they are the best thing to ever hit agriculture. both arguments are correct and both will based on rigorous science. its just the intepretation of the results and the weight someone adds to each! self-preservation rules..........



anthonyk
12/11/2007
6:58:35 PM
On 12/11/2007 GravityHound wrote:
>trust scientists to give reliable numbers - ha! scientists may be philosophically
>objective but in reality, subjectivity rules. i should know - i am a scientist.
>an agricultural ecologist. a brief example. ask me about GM crops and i'll
>rant and rave basically about the potential damage they might cause. ask
>an agricultural ecologist employed by Monsanto about GM crops and he will
>tell you they are the best thing to ever hit agriculture. both arguments
>are correct and both will based on rigorous science. its just the intepretation
>of the results and the weight someone adds to each! self-preservation rules..........

sure.. anyone is going to pick the criteria that best suit their biases/gripes/interests etc. at least a scientist is more likely to use a test that is empirical instead of emotional and to use valid studies, regardless of what criteria were chosen to be used for the comparison.

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There are 128 messages in this topic.

 

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