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  1. 16 Jun '14 17:56 / 2 edits
    here is a link that shows that this is perfectly possible:

    http://phys.org/news/2014-06-turbine-payback.html
    "...they conclude that in terms of cumulative energy payback, or the time to produce the amount of energy required of production and installation, a wind turbine with a working life of 20 years will offer a net benefit within five to eight months of being brought online.
    ..."

    Obviously, this will be true with or without subsidies. I don't see how anyone can argue, like some sometimes do, that wind will always be uneconomical with figures like that.
  2. 16 Jun '14 20:24
    Originally posted by humy
    I don't see how anyone can argue, like some sometimes do, ....
    Its easy. Just be on the payroll of an oil company.
  3. 16 Jun '14 21:07
    The article doesn't say it will pay for itself, it says it will recover the energy used in making it. Not quite the same thing.
    The problem with wind and solar is the cost is upfront and you benefit for many years afterwards. With oil and gas, the initial cost is lower, and the environmental costs come later - and most critically, typically get payed for by someone other than the power company.
  4. 16 Jun '14 23:18
    Originally posted by twhitehead
    The article doesn't say it will pay for itself, it says it will recover the energy used in making it. Not quite the same thing.
    The problem with wind and solar is the cost is upfront and you benefit for many years afterwards. With oil and gas, the initial cost is lower, and the environmental costs come later - and most critically, typically get payed for by someone other than the power company.
    Which is why the best free market incentive is a carbon tax [revenue neutral for preference]

    http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/jun/13/how-revenue-neutral-carbon-tax-creates-jobs-grows-economy
  5. Standard member DeepThought
    Losing the Thread
    17 Jun '14 01:22
    Originally posted by twhitehead
    The article doesn't say it will pay for itself, it says it will recover the energy used in making it. Not quite the same thing.
    The problem with wind and solar is the cost is upfront and you benefit for many years afterwards. With oil and gas, the initial cost is lower, and the environmental costs come later - and most critically, typically get payed for by someone other than the power company.
    There are ecological issues with wind farms, such as diced birds and bats. I doubt the analysis took that into account. But given the number of birds the domestic cat population get through in a year (from memory 27 million in the U.K.) that shouldn't be too much of a problem.

    Given the British government is allowing EDF to take risks with an AGR which should really be decommissioned [1] there is something of an energy crisis which needs addressing and wind simply can't do it all. In the light of that I'm skeptical about letting EDF build new reactors as safety appears not to be their primary concern. AGRs are great from a safety point of view (allowing for the fact it's an old design and overcomplicated) as there is no water and no Zirconium so the problem with hydrogen build up during a reactor overheat cannot happen. I don't understand why they insist on PWRs instead of improving the AGR to reduce the complexity of the design and the efficiency problem - Zirconium has a much smaller neutron absorption cross-section than steel cladding, so they need either to find a material that absorbs fewer neutrons than steel but co-exists with carbon dioxide, or use a different gas (helium?).

    [1] http://www.bbc.co.uk/news/uk-27691207
  6. 17 Jun '14 07:32
    Originally posted by twhitehead
    The article doesn't say it will pay for itself, it says it will recover the energy used in making it. Not quite the same thing.
    The problem with wind and solar is the cost is upfront and you benefit for many years afterwards. With oil and gas, the initial cost is lower, and the environmental costs come later - and most critically, typically get payed for by someone other than the power company.
    The article doesn't say it will pay for itself, it says it will recover the energy used in making it. Not quite the same thing.

    But close enough. Generally, ignoring labor costs, the energy costs for gathering material (such as through mining) and then manufacturing something and then transport and installing it is roughly proportional to the total cost of all that. It is a reasonable assumption that, ignoring labor costs, if it pays for its energy costs (of manufacture, installation etc ) within a few months, it pays for all its costs within a few months.
  7. 17 Jun '14 13:05
    Originally posted by DeepThought
    There are ecological issues with wind farms, such as diced birds and bats. I doubt the analysis took that into account. But given the number of birds the domestic cat population get through in a year (from memory 27 million in the U.K.) that shouldn't be too much of a problem.

    Given the British government is allowing EDF to take risks with an AGR wh ...[text shortened]... h carbon dioxide, or use a different gas (helium?).

    [1] http://www.bbc.co.uk/news/uk-27691207
    They would be better off investing in Molten Salt Reactors.

    They are more efficient, safer, and can use a wider range of fuels.
    Including Plutonium, and Thorium.
  8. 17 Jun '14 13:41
    Originally posted by DeepThought
    .....there is something of an energy crisis which needs addressing and wind simply can't do it all.
    But wind, solar, tidal and other renewables, could. I am not totally anti-nuclear on principle, but I do think that it is not economically the best choice any more - especially in first world nations. China can get away with new nuclear because they have far fewer regulatory issues to deal with. In the US and presumably the UK, it is no longer the best value for money. If wind and solar got the same levels of government subsidy that nuclear got, then they would work out cheaper, and could probably be brought online faster than new nuclear plants.
    The only thing holding back renewables is politics.
    Solar especially changes the equations for everyone involved in power, and since many powerful companies, and the government itself, will loose out, there is significant political opposition.
  9. 17 Jun '14 22:46
    Originally posted by twhitehead
    But wind, solar, tidal and other renewables, could. I am not totally anti-nuclear on principle, but I do think that it is not economically the best choice any more - especially in first world nations. China can get away with new nuclear because they have far fewer regulatory issues to deal with. In the US and presumably the UK, it is no longer the best va ...[text shortened]... companies, and the government itself, will loose out, there is significant political opposition.
    Part of the reason that electronics are expensive [among many other things]
    is the limited supply of rare-earth metals that go into making them.
    Which are currently largely sourced from china.

    Another major potential source is the USA, which has large deposits, that
    are largely untapped due in no small part to the fact that with these
    rare-earth's you get large amounts of Thorium, and the USA has strict
    rules about handling and disposing of radioactive materials which make
    it prohibitive to extract these rare-earth's.

    If we built molten salt reactors [which are potentially much cheaper than current
    reactors, due to operating at atmospheric pressure and not needing a very expensive
    steel containment vessel [among other benefits]]
    which can use Thorium as
    a fuel then we gain a fuel supply that will last for centuries if not millennia, is very safe,
    is low/zero carbon, and frees up the extraction of lots of valuable rare-earth metals which
    are the basis of a lot of new technologies.

    Couple this with economies of scale demonstrated by France, which has had long term
    stable low electricity prices due to large nuclear investment, and you have something
    that is easily competitive.

    Also did I mention that molten salt reactors can eat nuclear waste which means that
    after we're done [moved to fusion?] we have less waste than today rather than more...

    They also have a very small land use footprint, and can be built close to cities and/or
    industry where the power is used. Which reduces the need for long distance power
    transmission reducing the cost of the grid and reducing transmission losses.


    Most cost analyses are far too simplistic.

    Also, there is value in redundancy, having multiple sources of power makes you more
    secure, and less vulnerable to a disaster [natural or economic] that effects some more
    than others.


    We can't practically do geothermal in the UK [sadly otherwise I would be going all out
    for geothermal power] and we need something low/zero carbon with a small footprint to
    produce our base-load. Nuclear fits that bill perfectly.

    But it has a big upfront cost, and takes time to install.

    And successive governments have failed to plan ahead or act decisively [while doing the
    right thing].
  10. Standard member DeepThought
    Losing the Thread
    17 Jun '14 23:34
    Originally posted by googlefudge
    They would be better off investing in Molten Salt Reactors.

    They are more efficient, safer, and can use a wider range of fuels.
    Including Plutonium, and Thorium.
    I'm assuming a better design bear in mind. The nice thing about an AGR is that if it starts to go wrong Fukishima style you can just blast carbon dioxide through it, which is the big plus with gas cooled reactors. This isn't available with PWRs or molten salt reactors.

    A magnox reactor, Chapelcross had a single fuel rod cladding fail (this is a partial meltdown), due to a problem with cooling in 1967, it was successfully cleaned out and the reactor could be restarted in 1969, Chapelcross started decommissioning in 2004. Had that been a PWR then there'd have been a disaster.

    There was a gas cooled reactor called the Dragon reactor that was helium cooled, its purpose was to test fuel. I like the safety aspects of gas cooled reactors. A modern design could easily be better. There was a political decision made in the 1980's to stop investing in the Gas Cooled reactor program, basically because the Thatcher government thought that buying in PWRs was the way forward. Sizewell B produces expensive electricity. The AGRs are actually pretty much economically viable.

    The difficulty with Molten salt reactors, is that there's been a few experimental ones in the 1950s, but no one has built a commercial one so we don't know the behaviour as well.

    There's no principled reason why thorium or any other nuclear fuel shouldn't be used in a gas cooled reactor.
  11. 18 Jun '14 00:22
    Originally posted by DeepThought
    I'm assuming a better design bear in mind. The nice thing about an AGR is that if it starts to go wrong Fukishima style you can just blast carbon dioxide through it, which is the big plus with gas cooled reactors. This isn't available with PWRs or molten salt reactors.

    A magnox reactor, Chapelcross had a single fuel rod cladding fail (this is a part ...[text shortened]... incipled reason why thorium or any other nuclear fuel shouldn't be used in a gas cooled reactor.
    Molten Salt Reactors cannot melt down.

    They are already molten by design.

    If an MSR runs too hot it melts the plug of actively cooled salt in the outlet
    pipe and the entire contents drains out of the reactor into a secondary
    chamber specifically designed to passively hold the cooling and now sub-critical
    reactor contents.

    Also, and crucially, the MSR constantly filters out the reaction by products that
    provided the excess heat that was the problem at Fukishima so it cools to cold
    shut-down much faster.

    Also this constant filtering out of by-products means that you don't have a fuel
    rod that becomes unusable with still 80% fuel content.

    AGR's still need active cooling in the event of something going wrong.

    MSR's passive fail to safe. And are more efficient in terms of fuel usage.


    I am aware that research on MSR's lags behind other types because research was
    focused on reactors that work well in Nuclear Submarines [ie PWR's] and that there
    is a need of investment in research needed for them.
    Research currently being conducted in china, which is very seriously looking at MSR's,
    probably because of all the excess Thorium generated by their rare-earth metal mining.

    I don't think Thorium is really viable as it needs to be converted into U233 in a reactor
    and it is the U233 which is the fissile materiel. Which means in conventional reactors
    you would need to constantly be refining and reprocessing your fuel rods as the isotope
    mix changed. This happens naturally in an MSR as part of normal continuing operations.


    Also, Windscale was a Gas-cooled reactor. Admittedly it was a badly designed one, but it
    demonstrates the potential for Fukishima style disasters in AGR's.
    It's still possible for an AGR to meltdown, they still need active cooling and expensive pressure
    containers.
  12. Standard member DeepThought
    Losing the Thread
    18 Jun '14 00:27
    Originally posted by googlefudge
    Molten Salt Reactors cannot melt down.

    They are already molten by design.

    If an MSR runs too hot it melts the plug of actively cooled salt in the outlet
    pipe and the entire contents drains out of the reactor into a secondary
    chamber specifically designed to passively hold the cooling and now sub-critical
    reactor contents.

    Also, and crucial ...[text shortened]... ible for an AGR to meltdown, they still need active cooling and expensive pressure
    containers.
    Windscale was not a reactor. Windscale was a nuclear barbecue. In any case the cooling wasn't the problem, they'd failed to understand the effects of neutron flux on graphite, so a fire started.

    What if the plug fails?
  13. 18 Jun '14 00:46
    Originally posted by DeepThought
    Windscale was not a reactor. Windscale was a nuclear barbecue. In any case the cooling wasn't the problem, they'd failed to understand the effects of neutron flux on graphite, so a fire started.

    What if the plug fails?
    Then the reactor shuts down.

    The plug is made of 'frozen' Thorium salt.

    Basically you have a pipe leading from the base of the reactor chamber
    to the secondary chamber.

    This pipe is actively cooled so that the salt flowing into it cools below it's
    freezing point and solidifies, blocking the pipe.

    In the event of a coolant failure, or the reactor becoming too hot, the plug
    melts and the contents drains out.

    Passive failure to cold shutdown.

    Shown in this diagram.

    http://upload.wikimedia.org/wikipedia/commons/0/08/Molten_Salt_Reactor.svg

    Freeze Plug --> Emergency Dump Tanks
  14. 18 Jun '14 06:14 / 1 edit
    Originally posted by googlefudge
    If we built molten salt reactors [i][which are potentially much cheaper than current
    reactors,

    Couple this with economies of scale demonstrated by France, which has had long term
    stable low electricity prices due to large nuclear investment, and you have something
    that is easily competitive.
    Much as I like the idea of Thorium reactors, the problem with Nuclear in a place like the US, is the regulation adds significantly to the costs, and the time to market for new ideas. This makes Thorium reactors practically impossible.
    As for the economies of scale, the same applies to wind and solar and if you put the same amount of investment into them as you are proposing for thorium reactors, they would work out cheaper, and have many other benefits besides.

    We can't practically do geothermal in the UK
    Why not?

    http://en.wikipedia.org/wiki/Geothermal_power_in_the_United_Kingdom
    Deep geothermal resources could provide 9.5GW of baseload renewable electricity – equivalent to nearly nine nuclear power stations – which could generate 20% of the UK’s current annual electricity consumption;
    Deep geothermal resources could provide over 100GW of heat, which could supply sufficient heat to meet the space heating demand in the UK;
  15. 18 Jun '14 06:35 / 1 edit
    Originally posted by twhitehead
    Much as I like the idea of Thorium reactors, the problem with Nuclear in a place like the US, is the regulation adds significantly to the costs, and the time to market for new ideas. This makes Thorium reactors practically impossible.
    As for the economies of scale, the same applies to wind and solar and if you put the same amount of investment into them ...[text shortened]... of heat, which could supply sufficient heat to meet the space heating demand in the UK;[/quote]
    http://en.wikipedia.org/wiki/Geothermal_power_in_the_United_Kingdom

    I didn't know this! I wouldn't have imagined that UK geothermal would be viable but I learn something new every day.
    I wonder how cost effective it is esp compared with other renewables and oil-powered or coal-powered electric generation -I suppose that just depends and is very difficult to say.