Nuclear energy and society

Discussion in 'Science & Society' started by Keln, Feb 4, 2011.

  1. Skeptical Registered Senior Member

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    1,449
    Why do we keep overlooking the thermal solar stuff?
    1. It is still too damn expensive at 25 c per kwh.
    http://en.wikipedia.org/wiki/Cost_of_electricity_by_source
    2. It does not operate at night.

    Chernobyl releasing more radioactivity than all the coal power for 100 years? Please supply a reference to this. Please ensure that your reference comes from a reputable source, and not some half baked lobby group.

    Scientific American states clearly that coal ash contains way more radioactivity than the effluvium from coal fired power stations.
    http://www.scientificamerican.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste

    And I quote :
    "estimated radiation doses ingested by people living near the coal plants were equal to or higher than doses for people living around the nuclear facilities. At one extreme, the scientists estimated fly ash radiation in individuals' bones at around 18 millirems (thousandths of a rem, a unit for measuring doses of ionizing radiation) a year. Doses for the two nuclear plants, by contrast, ranged from between three and six millirems for the same period. And when all food was grown in the area, radiation doses were 50 to 200 percent higher around the coal plants"

    Nuclear power too expensive?
    Not so, as the data indicates, at 12 c per kwh. It is in the same cost realm as coal, hydroelectricity and gas, and half the cost of thermal solar.
     
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  3. quadraphonics Bloodthirsty Barbarian Valued Senior Member

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    My bad - dropped a zero in my back-of-the-envelope estimate. The average power output of a US nuclear plant is about 900MW.

    Note that the USA alone right now has 5GW of thermal solar under construction, to be online within 4-5 years. This is as much as 6 nuclear power plants, all without any concerns of fuel/waste production/transports/handling/disposal, the risk of nasty disasters, etc.
     
    Last edited: Mar 2, 2011
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  5. quadraphonics Bloodthirsty Barbarian Valued Senior Member

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    If baseline operation is desired (i.e., when the sun is not shining), there exist practical heat-storage mechanisms that can enable thermal solar stations to operate round-the-clock. Many of the newer ones are being built with such capabilities.

    But addressing peak usage during sunny days is almost as important, since that represents a huge amount of the overall energy consumption (much of it for operating air conditioners to cancel out the solar heating of buildings).
     
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  7. Skeptical Registered Senior Member

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    To quad

    Any electricity generating system that requires intermittent flows of energy to be stored run into the laws of thermodynamics. You cannot store energy and later use it to generate electricity without substantial energy loss. The amount of energy loss varies according to the system, but averages at about 50%.

    This needs to be factored into cost calculations. If solar thermal energy generates electricity at a cost of 25 cents per kilowatt hour, then electricity generated from stored solar thermal will cost 50 cents.

    OK. That is a simplistic calculation and it may not be exactly correct, but the principle is correct.
     
  8. billvon Valued Senior Member

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    12,725
    The Ukranians are now making money taking tour groups through Chernobyl. The area around the nuclear power plant is now the most diverse and healthy ecosystem in the Ukraine, due to the lack of people.

    "In the 20 years since the accident, the sum effect for the flora and fauna in the highly radioactive, restricted zone has been overwhelmingly positive in favor of biodiversity and abundance of individuals. For example, researchers have experienced numerous sightings of moose (Alces alces), roe deer (Capreol capreolus), Russian wild boar (Sus scrofa), foxes (Vulpes vulpes), river otter (Lutra canadensis), and rabbits (Lepus europaeus) within the 10-km exclusion zone; however, none of these taxa were observed outside the 30 km zone."

    "There has been an ongoing scientific debate about the extent that flora and fauna of the zone were affected by the radioactive contamination that followed the accident. No scientifically documented cases of mutant deformity in animals of the zone were reported other than partial albinism in swallows and insect mutations. There have been individual eyewitness reports of other animal mutations but no comprehensive statistical analysis has been completed to date. The cloud of heavily polluted dust left the Red Forest (Rudyi Lis)—a strand of highly-irradiated pine wood near the plant which was subsequently bulldozed.

    There have been reports that wildlife has flourished due to significant reduction of human impact. For this reason, the zone is considered by some as a classic example of an involuntary park. Populations of traditional Polesian animals (like wolves, wild boar and Roe Deer), red deer, moose, and beaver have multiplied enormously and begun expanding outside the zone. The area also houses herds of European wisent and Przewalski's Horses released there after the accident. Even extremely rare lynx have appeared, and there are reports of tracks from brown bear, an animal not seen in the area for several centuries. Special game warden units are organized to protect and control them."

    Chernobyl was undoubtedly a disaster; the one saving grace is that such an incident can't happen in US reactors, since they are designed with negative void coefficients. However, the popular portrayals of Chernobyl as a blighted, lifeless wasteland have no basis in reality. Indeed, it has become one of the most important wildlife refuges in Russia.
     
  9. quadraphonics Bloodthirsty Barbarian Valued Senior Member

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    I don't think that's accurate, at least as applied to heat storage for solar thermal. My understanding is that the energy loss in that scenario (heat up during the day, discharge at night) is nowhere near 50% - the storage units are advertized as being able to store heat for multiple weeks, so the level of loss over the course of a single day should be very limited.

    The increase in costs for heat storage are more to do with capital costs (all that medium, insulation, heat pumps, etc. costs money and takes up space) and the fact that these systems typically require some power to operate.

    You miss another important factor about baseline usage - since you're able to sell electricity 24 hours a day instead of just 12, you make twice as much money for a given amount of sunlight and reflectors. That assumes that you couldn't just sell twice as much electricity during peak hours, but if that were the case you wouldn't be bothering to support baseline generation in the first place. In the cases where it's appropriate, heat storage means that you get to sell the excess power you generate during peak hours, instead of simply throwing it away. The companies that sell heat storage equipment for thermal solar advertize it as decreasing the cost of the resultant electricity.
     
  10. iceaura Valued Senior Member

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    24,102
    The newer systems cost less than half that. Your Wiki link shows some; scroll down past the DOE fictionalization, and see a table of more realistic - actual operation - costs for Australian setups, for example.
    With more realistic numbers and more alert arithmetic, such as assuming it does not cost as much to store power in bulk as deliver it thousands of miles away to retail customers, we might easily have $.11 @kwh straight delivery and maybe $.13 @ kwh stored and delivered.

    That would match the Australian's and Californian's actual numbers.

    If the storage ability is built in to the initial structure and included in the straight power cost overhead, storage cost is only the marginal cost of surplus operation plus the opportunity cost of not selling it on the grid immediately - fractions of a penny per kwh.
    As it turns out, complete extirpation by humans is worse for animals than background radiation damage (which the wildlife around Chernobyl does suffer from, in reduced fertility and so forth).

    No doubt people could live there as well, putting up with damaged lives in return for lives at all, if the choice were that or some kind of extermination.

    So?
     
    Last edited: Mar 6, 2011
  11. Skeptical Registered Senior Member

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    In fact, the scrolled down table gives a range of costs of 11.6 to 31.2 cents. Your above statement is, therefore, inaccurate.
     
  12. iceaura Valued Senior Member

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    Should have rounded up, to 12 cents?

    OK. Far less than nuclear, at any rate, even with the DOE fictions taken seriously - and with nuclear we know huge costs (such as military ventures and risks, and risk premiums in general) are simply omitted from the official numbers.
     
  13. Skeptical Registered Senior Member

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    Actually, nuclear has even greater potential for cost savings than solar thermal. The 12 cents per kwh cost is mainly commissioning and decommissioning. The actual fuel cost is less than 2 cents per kwh. If a nuclear power station can be built that will last 50 years instead of 30, the cost per kwh will drop dramatically. And that is exactly what modern nuclear scientists are working on.
     
  14. iceaura Valued Senior Member

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    24,102
    A silly fiction like that is found largely by excluding major costs of commissioning and decommissioning.

    And insurance, risk premium, security, waste handling, etc.
    Good for them. Thermal solar is in better shape than that already - with far less money invested, and far less needed for greater levels of improvement.

    (It occurs to me that we could do a benefit analysis of the failure to build nuclear power plants in Tunisia, Libya, Morocco, Algeria, etc - how much per kwh not generated are we saving, now, by not having to handle that situation? )
     
    Last edited: Mar 6, 2011
  15. Skeptical Registered Senior Member

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    iceaura

    Thermal solar is a lot more expensive than nuclear. Saying it is cheap does not make it so.
     

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