The Forum > General Discussion > Low Carbon emission power generation
Low Carbon emission power generation
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Posted by DEMOS, Wednesday, 9 January 2008 7:38:08 PM
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Solar thermal plants work by having a bunch of mirrors reflecting light from the sun onto a focus. If you sit at the focus, then in each mirror you can see the sun, so it gets really hot.
Cover the sun with cloud, and at the focus you see cloud reflected in each mirror, and it doesn't get anything like as hot. After all, if you look elsewhere you also see cloud. Putting sufficient solar cells on residences to remove their grid dependence would be ruinously expensive even before allowance is made for the batteries required to handle night time and overcast days. Wave power is unproven despite decades of R&D. BTW, the energy in a wave is proportional to the square of its amplitude, and there isn't much energy in small waves. Most of the energy is available during storms. Hot Rocks is the only thing other than nuclear (and continuing to burn coal, or moving to natural gas, which is limited) that even looks plausible for base load. As for the ten year horizon, nothing we do now will make much difference in ten years. We'll have to cope with 10 years of climate change come what may. Sylvia. Posted by Sylvia Else, Wednesday, 9 January 2008 10:28:15 PM
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Hello Sylvia,
Example modern generators use Carbon dioxide or Helium in place of steam to supply the drive pressure. These active gasses are cooled in the same manner as a gas fridge/freezer, so the by product of operation is Air conditioning, Chiller, Fridge or Freezer all for free. 350 megawatt steam turbine generator are 40%+ efficient, require steam at 550c heat,(ruling out non fossil fuels) evaporate 150 litres of water per second and require even more for cooling. Modern generators use the Hydro turbine 90%+ efficient, recycle all water and the gas used to provide the water pressure. 350 megawatt generator requires 60c- which can be supplied by renewable fuel including Methane gas. They use no water. Smaller models need much lower heat (0c-10c) and be powered by the pressure obtained by temperature difference inside and outside the house. Methane gas is not only produced by animals but humans too, and supply lines are allready in place. Burning Methane stops it going into the atmosphere increasing Global Warming. Posted by Only Human, Thursday, 10 January 2008 6:36:22 AM
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There does seem to be an assumption that everyone "needs" base-load power. If it really was the case that no-one was able to perfect politically-viable technology capable of providing enough power to ensure that everyone had access to cheap electricity anytime they wanted, then there's no real reason we couldn't adapt to electricity not being universally available all the time, or at least being far more expensive in times where supply was limited by lack of sun/wind/waves/whatever.
But I suspect if Australia had to choose between that option and nuclear power, we'd go with the latter. Posted by wizofaus, Thursday, 10 January 2008 8:26:49 AM
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I think in the long run there will be many different sources of electricity.
Re wave power, there is an experimental system near Pt Kembla and I read where they are now installing a number of other systems along the coast, so it must have been economically viable. Ok on the power being to the square of the wave height. Well that is better than wind which is to the cube of the wind speed. So they only work efficiently in a full gale. Bit like CO2 and global warming where the effect of CO2 reduces logarithmically. Thats why putting more CO2 into the atmosphere won't have much effect Posted by Bazz, Thursday, 10 January 2008 9:42:07 AM
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the grand mother of all thermal furnace circa 1970 http://en.wikipedia.org/wiki/Solar_furnace run by E.D.F. the French electricity authority " Electricite de France " , who also run the first sizable tide power generation station circa 1966 http://en.wikipedia.org/wiki/Rance_tidal_power_plant This authority has a generation of 470 TWh that is Tera/Watt/hour They provide cheap , plentiful power , in fact they export it to neighboring countries , their production is 75% nuclear , 16% hydro anybody who talk of wind power or solar doesn't really grasp the concept of a modern society , " alternatives " are highly subsidized toys riding on the back of cheap power manufacturing , show me a solar power factory running on its own products and I will believe , but no they run on the good old fossil fueled grid , that is hypocrisy , as for funding research , you can research santa claus as much as you want it's not going to make toys appears on their own no matter how much you wish it or spend on it . personal consumption is the least of the problem even if for self absorbed city dwellers it seems to be the Posted by randwick, Thursday, 10 January 2008 10:02:54 PM
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radical reduction of greenhouse gases is a political problem, not scientific, not engineering. radical reduction may be the difference in racial survival, or at least the difference in catastrophic climate change.
if you plan to be alive 10 years from now, email every politician in turn, saying "action now! or no vote." then do it again, and again, and tell your friends. this is too serious a question to leave in the hands of politicians, but ozzies have knee-capped their power by submitting to pollie rule. at least remind them you are watching, and have cricket bat in hand.
it wouldn't hurt to mention capping population, either. that is the proximate cause of most of humanities problems.