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    This is a bit of a multi-leveled thread really, so apologies for that! The thinking was inspired by reading about how when Theresa May becomes Prime Minister she will be handed the keys to our nuclear arsenal, or rather our nuclear submarine.

    Here's some questions for you to think about:

    1. Why don't we use nuclear energy more?

    2. What is the likelihood of a Nuclear War?

    3. Do you think terrorists will ever get their hands on a bomb and detonate it?

    Bonus Question:

    - What would be the best thing about living in a post-Nuclear world? (Aka like the Fallout series for those that are familiar with it)

    To leave a quote from the mastermind that was Albert Einstein,

    "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."
    Spoiler:
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    If bombs do go off then at least we could hide inside a refrigerator like Indiana Jones
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    1: because most people are afraid of it after events which have occurred from nuclear power plants even though said events were due to env issues or failure in design/total idiocy.

    2: unlikely. Nuclear weapons are deterrents and it's not like all of the countries that own them hate each other like during the Cold War.

    3: probably not. These weapons would be in very high security facilities and are mostly as missile I believe which would need to be fired from a base.

    Bonus: I can become rich by raiding supermarkets for Coca Cola.
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    (Original post by Vikingninja)
    1: because most people are afraid of it after events which have occurred from nuclear power plants even though said events were due to env issues or failure in design/total idiocy.

    2: unlikely. Nuclear weapons are deterrents and it's not like all of the countries that own them hate each other like during the Cold War.

    3: probably not. These weapons would be in very high security facilities and are mostly as missile I believe which would need to be fired from a base.

    Bonus: I can become rich by raiding supermarkets for Coca Cola.
    Maybe we should start collecting those bottle caps

    It would be interesting to have another go at nuclear energy. Obviously the events of Chernobyl were catastrophic but as you said, it was more to do with the design behind it. Who knows, if we run out of coal and oil then we may turn to nuclear!
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    (Original post by PugDevil)
    Maybe we should start collecting those bottle caps

    It would be interesting to have another go at nuclear energy. Obviously the events of Chernobyl were catastrophic but as you said, it was more to do with the design behind it. Who knows, if we run out of coal and oil then we may turn to nuclear!
    I'll give the causes of Chernobyl and the one in Japan during the tsunami a few years ago.

    Chernobyl (design failure and idiocy):
    Control rods had some material on the end of them which expanded as it heated up (design flaw)
    They did an experiment where they raised the control rods so that the nuclear reactions were much more numerous to raise the temperature (not sure why).
    Temperature became too high and when they lowered the control rods they got stuck because this material on the end had expanded too much and so the reactions couldnt be slowed down and so it went into meltdown.
    Also bonus stupidity in design: there was a massive irradiated reservoir below the reactor and if the massively heated reactor fell into it by melting the supports and floor it would cause a massive steam explosion and the irradiated steam would've made half of Ukraine uninhabitable.

    Japan (env issues):
    Earthquake took out power lines so the power grid was disconnected from the power plant (the grid keeps it running).
    The power plant had backup generators to keep all functions continuing in an emergency but a tsunami took these out and so the reactor went meltdown.

    I would say that it would be safe in the uk because we aren't idiots who make... Totally ridiculous design flaws and experiments and we are environmentally safe. Also a lot of nuclear power plants are also designed to be protected from attacks.

    Really the reason why it's not pushed for so much here is because of the media not exactly helping explain that the causes of other events don't really applying here and so a large part of the public opposes to a power plant being even a moderate distance away.
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    I'm actually applying for Nuclear Engineering as a course, so this is an interesting thread for me.

    1. I feel the public has been misled, but it is a tough subject that requires external reading to fully appreciate. There are lots of concerns, whether waste or proliferation or safety. The problem is, all three of these concerns revolve around the design of the reactor. The costs of nuclear seem artificially high, due to regulatory requirements.

    In any nuclear discussion, Nuclear Energy comes in two main flavours - fission when you split up large atoms, or fusion when you fuse small ones as the entire Universe wants to make iron. This post is about Nuclear Fission.

    I'll first define a few terms.

    Radiation simply refers to fast-moving particles, and the types coming from radionuclides are called ionising radiation. If it hits a cell, by analogy it is like opening up your DNA file in notepad and editing the code. It happens all the time, the sun emits ionising UV radiation and the granite beneath you produces some radon gas which is radioactive. It's okay, except once in a while a cell becomes too damaged or cancerous.

    Penetrating power refers to how well it could penetrate through various materials, range refers to the distance travelled before the energy of the radiation is near zero, and the ionising ability refers to the chance of ionising something when it passes through.

    Alpha particles can be stopped by a thin layer of skin (helium nuclei are relatively huge) - there's no harm in holding an alpha source, but if you ingested it then it would immediately ionise the nearest thing (meaning it damages your vital organs). It is important to know this because Fukushima Daichii released alpha-emitting iodine into the atmosphere.

    Gamma radiation has infinite range (it's a high energy form of light), high penetrating power (requiring thick lead or concrete to block) but is unlikely to ionise anything when it passes through you. It is still quite dangerous when exceeding certain tolerances though.

    Beta radiation (fast electrons) is moderate on everything.

    Nuclear waste is a complicated issue, but you have to understand that not all waste is equal in quite a few ways. Suppose you had two pieces of nuclear waste material, one which lasts 10 days and another a million years, which one would you presume is more likely to hurt you? If you guessed a million years (intuitive), it would be deadly wrong.

    I'll ask another way. If I told you that a candle and a dynamite releases about the same amount of energy, which one do you think would hurt you if you held one when lit? It's obviously the dynamite, because it explodes - the energy rushes out all at once, and the energy doesn't get dissipated. It's the same principle with radioactive materials, short half lives usually mean a greater hazard

    The stuff that lasts a million years, you could probably make a plate and eat off.

    The other issue is the quantity of waste. If an average person with a US/European standard of living needs about 30kWh of electricity, what does it take to produce it? A majority of power is produced using finely ground coal-powder. It takes about 30 pounds of coal to produce your electricity needs, which is about a large rucksack full.

    The combustion of which emits NOx, SOx, CO2, and other harmful pollutants like heavy metals and soot into the atmosphere. It also emits radioactive "NORMs" (naturally occuring radioactive materials). It does get diluted, but very large numbers in the hundreds of thousands have diseases (cardiovascular and respiratory) directly related to air pollution mainly from power generation and motor vehicles.

    Current generation power stations (III or lower) need only hundredths of a gram of U235, or about 4 grams of natural uranium for the equivalent amount of energy. The reason why the numbers are so high is because over 95% of the fuel is being dumped as "waste" - it's actually not waste at all.

    A lot of the waste issues are born from the fact that the fuel is put through once and disposed of, if it was properly reprocessed or "bred" then we could use up all the energy in natural uranium instead of less than 1% of it (the percentage of U235, the fissile isotope, present). It is politically controversial because there may be proliferation risks associated depending on the exact details and designs of the reactor, which is usually too technical for Parliament to interpret.

    A coolant refers to the medium that carries the energy from the nuclear material to the thermal exchange. The safety issues are mainly to do with the water used as a coolant. If you heat up a pot of water, it gets hotter and hotter and when it reaches 100C, it starts to boil. The steam takes up a lot of volume, about a thousand times that of water.

    "Gen III" or lower reactors, referring to the current generation of Nuclear Power Plants, are almost exclusively based on water-coolants. PWR is a "Pressurised Water Reactor", BWR is a "Boiling Water Reactor", and they are both subclasses of LWRs - "Light Water Reactors". Light Water contrasts with Heavy Water which contains hydrogen atoms with a neutron attached to it, called deuterium.

    Heavy Water slows down neutrons by colliding with them, which increases the chance that the neutrons will hit a radioactive nucleus - it acts as a moderator.

    The entire design of a nuclear power plant is based around this issue - it has to have something called a containment building which is a large concrete building surrounding the reactor/pressure-vessel should the reactor fail and a breach occurs (usually when pressures are too high). It is what contributes to the cost of construction, decomissioning, and environmental/safety issues.

    The design of current nuclear reactors require an active power source to ensure there is no meltdown, which seems quite silly after Fukishima Daiichi.

    In Fukushima Daiichi, a tidal wave breached the sea wall (which was constructed too small as it was deemed an unlikely event during the lifetime of the reactor) and caused what is known as a common mode failure where multiple backup systems failed simultaneously. The failures led to its eventual meltdown and several hydrogen explosions caused by the fission of water and a heat source in the reactor.

    Proliferation deals with the part that involves enrichment, as 1% uranium won't burn the same way coal diluted with sand doesn't like to burn. If it's possible to enrich to 5%, then it's also possible to enrich to above 90% (weapons grade). This issue is notoriously difficult to manage.

    A lot of these problems are inherent to a particular design, and as it takes many years to research/develop alternative fuels and coolants and designs and further to approve/construct/connect-to-national-grid/export - nuclear energy won't be popular until it becomes clear that it is practically impossible to reach the Paris/Kyoto climate targets without it, the cost of energy to rise, and the intermittency of renewables cause the lights to go out more often.
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    (Original post by PugDevil)
    This is a bit of a multi-leveled thread really, so apologies for that! The thinking was inspired by reading about how when Theresa May becomes Prime Minister she will be handed the keys to our nuclear arsenal, or rather our nuclear submarine.

    Here's some questions for you to think about:

    1. Why don't we use nuclear energy more?

    2. What is the likelihood of a Nuclear War?

    3. Do you think terrorists will ever get their hands on a bomb and detonate it?

    Bonus Question:

    - What would be the best thing about living in a post-Nuclear world? (Aka like the Fallout series for those that are familiar with it)

    To leave a quote from the mastermind that was Albert Einstein,

    "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."
    Spoiler:
    Show
    If bombs do go off then at least we could hide inside a refrigerator like Indiana Jones
    1. Obviously it's partially due to public fears but it's oversimplifying the situation to act as if nuclear power is some panacea that would solve all of our problems if the public was just better informed. Nuclear power stations are currently massive infrastructure projects that require a lot of long-term financial stability for companies to be willing to invest and generally, this means guarantees of subsidies on timescales of decades, which a lot of countries are unwilling to do. I think nuclear energy had a huge amount of potential put this has largely been wasted due to the inability of companies and countries to develop and proliferate modular reactors and innovative alternatives like breeders and salt reactors early enough and I think they're going to be outcompeted by renewables in the not-too-distant future.

    2. Higher than most people believe. The risk isn't intentional nuclear war, the risk is that weapons are deployed by mistake - either by a system malfunction or in response to a perceived threat which could either be a genuine error or a ruse by a third party.

    3. From what I've read, it's very unlikely that a terrorist organisation would be able to build a fully functioning thermonuclear device. Its more feasible to imagine a terrorist organisation developing a dirty bomb, but the risk of these has been exaggerated and it would be more of a psychological weapon than a weapon of mass destruction.
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    Nuclear Fusion

    It is perhaps the most ideal source of energy that you could imagine. It is plentiful, it is cheap*, it is abundant, it is completely clean and devoid of nuclear waste*, does not cause harmful emissions of flue gases or heavy metals or soot-based pollutants or leave tailings, it is energy-dense, it is not land-invasive or intermittent, it does not depend on local weather, it can sustain human society for millions of years to come (about as "sustainable" as any source can get), it does not require batteries, it is reliable, and it is low-entropy.

    * The fuel costs are practically zero, but the construction and R&D and such will be one of the most costly endeavours of human history. But then again, the smartphone is essentially a trillion dollar R&D project but it is cheap because it is mass produced and economies of scale is achieved.
    * The nuclear fuel itself won't produce any unstable radionuclides as a decay-product, as it fuses into stable isotopes of helium, but as it produces neutrons, this can cause the surrounding materials to become irradiated.

    It just happens to be extremely hard to do.

    If anyone has ever Googled what it takes to fuse nuclei together, you should know that it takes hundreds of millions of degrees to ignite. This is based on something known as the Lawson Criterion.

    "The center of the Sun is only twenty-seven million degrees" - the Sun is a lousy reactor, it gets away with it because sometimes it uses quantum tunneling to fuse and its efficiency doesn't matter that much - the average unit volume of compost releases more energy per unit volume than the average unit volume of Sun.

    It is also something that puzzles a lot of material scientists, there is nothing in the Universe that we know of that won't melt at those temperatures. If you tried to build a box around the Sun to power a steam engine, the box would melt. It's the same problem aerospace engineers have when they design engines - the exhaust is so absurdly hot that it would normally melt the parts.

    In aerospace engineering, the clever solution around the problem is to simply embed the tubes of liquid fuels into the rocket exhaust so it provides a cooling effect that prevents melting. In nuclear fusion, one of the approaches is to use magnetic confinement - moving electric charges are deflected by magnetic fields, so it can be "trapped" in a magnetic tube to avoid melting the multi-billion-dollar machine.

    This is where a lot of the expense goes - normal magnets won't cut it, so superconducting magnets (the same as MRI scanner types) are necessary. The industry that manufactures the cables for extremely large superconducting magnets don't even exist, so the R&D project has to pay for that too.

    JET in Culham (CCFE) has shown us that getting very close to the "energy return" is possible, but there are a lot of issues with materials to figure out before we could start doing Nuclear Fusion commercially. ITER is the proof of concept that Fusion is a viable pathway to generate energy, then DEMO1 for designing a electrical power plant from it, and DEMO2 for optimisation.

    Nuclear Fusion will probably take another 30-50 years, it's been said many times before but we've now learned that we were far too naive before. The way the funding has been allocated doesn't suggest to me that Fusion will come to market for a while to come, unless an alternative form of Nuclear Fusion that doesn't involve donut-shaped machines could demonstrably work.

    The materials challenges of not-melting/not-becoming-brittle-when-irradiated/not-absorbing-the-tritium-as-it-is-hundreds-of-thousands-per-gram/be-able-to-breed-tritium-without-terrorists-building-hydrogen-bombs-with-it and the-goshdarn-energy-losses-that-we-can't-figure-out-because-plasma are going to have to be addressed slowly but surely.

    It won't be taken seriously until ITER is completed because we haven't even proved we can get an energy return yet. I haven't really discussed the type that involves lasers because if you run the numbers, the amount of energy returned is so absurdly small that it has practically no chance of success.
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    (Original post by Plagioclase)
    I think they're going to be outcompeted by renewables in the not-too-distant future.
    I don't think that is necessarily the case, renewables are only cheap because it is highly subsidized (ie not true cost), made in China (ie cost of pollution from producing the PV panels are not factored in), and doesn't have to pay for its unreliability.

    The cost of maintenance on a solar farm is cheap, you just have to clean up some panels. But the cost of intermittency is not, the solution to that problem whether in Germany or Spain has always been to build a gas plant next door so that when there's a sudden drop of sun then you ramp up your gas.

    Wind is just as bad, if not worse. Too much wind and you have problems with harmonic frequencies, too.

    That isn't sustainable by any stretch, and grid-sized batteries or storage is ridiculously unfeasible. I mean, modern society/economies would crumble the same way Hurricane Katrina caused devastation if the power went out for more than a few days.

    The lifeblood of the city is its ability to produce surplus, dependent on its energy security. I think we'll be seeing fossil fuels, and innovative ways of reducing the impact of fossil fuels, for a while to come.
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    (Original post by Rather_Cynical)
    I don't think that is necessarily the case, renewables are only cheap because it is highly subsidized (ie not true cost), made in China (ie cost of pollution from producing the PV panels are not factored in), and doesn't have to pay for its unreliability.

    The cost of maintenance on a solar farm is cheap, you just have to clean up some panels. But the cost of intermittency is not, the solution to that problem whether in Germany or Spain has always been to build a gas plant next door so that when there's a sudden drop of sun then you ramp up your gas.

    Wind is just as bad, if not worse. Too much wind and you have problems with harmonic frequencies, too.

    That isn't sustainable by any stretch, and grid-sized batteries or storage is ridiculously unfeasible. I mean, modern society/economies would crumble the same way Hurricane Katrina caused devastation if the power went out for more than a few days.

    The lifeblood of the city is its ability to produce surplus, dependent on its energy security. I think we'll be seeing fossil fuels, and innovative ways of reducing the impact of fossil fuels, for a while to come.
    This is indeed what a lot of people believe but it really isn't particularly representative of the state of science right now. Let's not forget that nuclear energy is also highly subsidised and already in some countries such as Germany and the Arab states, solar energy has a similar cost per kWh as nuclear energy. And whilst the cost of fission power has pretty much been stagnant and is going to remain more or less stagnant, the cost of solar cells is plummeting at a rate that exceeds Moore's Law. Obviously $/kWh doesn't take into account the intermittency of PVs but assuming the current trajectory continues - and there's good reason to believe that it will - it will not be long until it significantly undercuts practically everything else.

    The construction of PV cells does indeed currently result in quite a lot of toxic by-products being formed but there is a huge amount of research being put in place into finding alternatives to ITO cells and there are many that are on the verge of reaching widespread use such as Perovskite-based cells.

    There are also many creative solutions to intermittency and the idea that we need to rely on battery-storage is just wrong. There are a whole range of solutions from smart-grids (probably the best and most cost-effective option) to paying industry to use energy in time of high energy supply to using vehicles as batteries to grid decentralisation to gas/liquid storage and so on. Again, there's a very big gap between the current state of solar economics, engineering and science and what people outside of the solar industry seem to believe. I've been to talks by world-leading scientists and economists in the field of solar energy and then subsequently gone to talks by nuclear engineers whose understanding of the state of solar technology is at least 10 years out of date, which is completely unacceptable given the exponential development of solar technology.

    A PV-powered world (possibly with nuclear as a backup) is absolutely feasible. Here are the main issues facing it. Firstly, because it is intrinsically decentralised, a PV-powered world would completely destroy energy utilities companies so there will be a huge amount of lobbying against any 'radical' pro-PV legislation by companies whose existence depends on a centralised energy model. Secondly, the steps required to make a PV-powered world feasible would require radical international agreements because it would fundamentally change the way our energy network operates, so the key question is whether this is politically feasible. Economically, it is completely feasible as research from institutions like the Oxford Institute for New Economic Thinking has shown, the question is whether countries will be willing to make such a big change for our long-term good.

    If you're interested in the arguments I've put forward then I'd recommend having a look at the Oxford Martin School Programmes for Renewable Energy and the Institute for New Economic Thinking. Quite a few of their lectures are on YouTube now, I believe.
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    (Original post by Plagioclase)
    Let's not forget that nuclear energy is also highly subsidised and already in some countries such as Germany and the Arab states, solar energy has a similar cost per kWh as nuclear energy.
    I'm less certain about the numbers on this one, what's the subsidy per kWh from these various sources? The true costs of nuclear is reflected in its price, the regulatory requirements internalise its negative externalities whereas the true costs of solar is not.

    (Original post by Plagioclase)
    And whilst the cost of fission power has pretty much been stagnant and is going to remain more or less stagnant, the cost of solar cells is plummeting at a rate that exceeds Moore's Law. Obviously $/kWh doesn't take into account the intermittency of PVs but assuming the current trajectory continues - and there's good reason to believe that it will - it will not be long until it significantly undercuts practically everything else.
    The cost of fission power on Gen III reactors won't go down any time soon, the fundamental issues surrounding construction/decomissioning costs will remain a barrier for as long as water remains the main coolant. It has lots of potential to go down with small modular reactors that use something like liquid sodium or molten salts as a coolant.

    The cost of solar PV isn't purely in the cells, the new grid you have to make (whether battery storage, or pumped hydro, or whatever) needs to be factored in. These issues don't exist with more conventional fuels like coal/oil/gas or nuclear. The countries you quoted aren't factoring those numbers in, thus gives the illusion that renewables are cheap.

    (Original post by Plagioclase)
    The construction of PV cells does indeed currently result in quite a lot of toxic by-products being formed but there is a huge amount of research being put in place into finding alternatives to ITO cells and there are many that are on the verge of reaching widespread use such as Perovskite-based cells.
    I'd be interested to see the numbers. I understand that single-junction polycrystalline silicon has a theoretical limit of about 30% from band-gap issues. I've heard a little about quantum dot technology, which seem very interesting but early in its development.

    (Original post by Plagioclase)
    There are also many creative solutions to intermittency and the idea that we need to rely on battery-storage is just wrong.
    Battery storage is one of the most effective ways to solve intermittency, it just happens to be incredibly resource-intensive.

    (Original post by Plagioclase)
    There are a whole range of solutions from smart-grids (probably the best and most cost-effective option) to paying industry to use energy in time of high energy supply to using vehicles as batteries to grid decentralisation to gas/liquid storage and so on.
    I don't think the incentives are aligned correctly for the "paying industry" idea to work all that effectively. Smart grids is a bit of a question-mark, that's a massive infrastructure project and people get pretty upset when their lights suddenly turn off - protesting and London riots upset.

    If you decided that it's too hard and you'll have to oversupply energy instead of storing it, that damages grid infrastructure. The prosperity we have in the Western world is a function of Engineering genius and the low-entropy and self-stored nature of coal and other fossil fuels.

    Vehicles as batteries idea depends on the numbers, what assumptions are you making to make that idea work?

    (Original post by Plagioclase)
    Again, there's a very big gap between the current state of solar economics, engineering and science and what people outside of the solar industry seem to believe. I've been to talks by world-leading scientists and economists in the field of solar energy and then subsequently gone to talks by nuclear engineers whose understanding of the state of solar technology is at least 10 years out of date, which is completely unacceptable given the exponential development of solar technology.
    Do you have any particular examples? And why does this matter? If you're particularly enlightened, then please share what you know

    (Original post by Plagioclase)
    A PV-powered world (possibly with nuclear as a backup) is absolutely feasible.
    This is conjecture, you have hardly provided any numbers on power/unit-land. The actual numbers coming from the Mojave desert is something like 5W/m2 - you would need to be incredibly invasive with your solar panels to produce anywhere near enough energy for a population.

    The average US/European lifestyle demands something in the order of 125kWh/day - a thousand square meters of land per person. If you take into account things like overunity water/air-source heat pumps and high efficiency vehicles, it would save a meager 30-40%.

    It might be possible for us, even with massive technological difficulty, but for the developing world that doesn't really care about global emissions and only care about energy security (a lack thereof -> a case of deadness) they'd continue with their use of fossil fuels.

    (Original post by Plagioclase)
    Here are the main issues facing it. Firstly, because it is intrinsically decentralised, a PV-powered world would completely destroy energy utilities companies so there will be a huge amount of lobbying against any 'radical' pro-PV legislation by companies whose existence depends on a centralised energy model. Secondly, the steps required to make a PV-powered world feasible would require radical international agreements because it would fundamentally change the way our energy network operates, so the key question is whether this is politically feasible. Economically, it is completely feasible as research from institutions like the Oxford Institute for New Economic Thinking has shown, the question is whether countries will be willing to make such a big change for our long-term good.

    If you're interested in the arguments I've put forward then I'd recommend having a look at the Oxford Martin School Programmes for Renewable Energy and the Institute for New Economic Thinking. Quite a few of their lectures are on YouTube now, I believe.
    It doesn't seem to me that you've actually run any numbers - the issues go far beyond "the energy lobby". The technological hurdles, land-invasiveness, etc are fundamental challenges to PV technology. It would be relatively sensible to consider deploying in Sub Saharan Africa that get 3x the solar flux than a country like the UK.

    Biomass doesn't produce much more than 0.2 watts per square meter, but at least it's low entropy.
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    (Original post by Rather_Cynical)
    I'm less certain about the numbers on this one, what's the subsidy per kWh from these various sources? The true costs of nuclear is reflected in its price, the regulatory requirements internalise its negative externalities whereas the true costs of solar is not.

    The cost of fission power on Gen III reactors won't go down any time soon, the fundamental issues surrounding construction/decomissioning costs will remain a barrier for as long as water remains the main coolant. It has lots of potential to go down with small modular reactors that use something like liquid sodium or molten salts as a coolant.

    The cost of solar PV isn't purely in the cells, the new grid you have to make (whether battery storage, or pumped hydro, or whatever) needs to be factored in. These issues don't exist with more conventional fuels like coal/oil/gas or nuclear. The countries you quoted aren't factoring those numbers in, thus gives the illusion that renewables are cheap.

    I'd be interested to see the numbers. I understand that single-junction polycrystalline silicon has a theoretical limit of about 30% from band-gap issues. I've heard a little about quantum dot technology, which seem very interesting but early in its development.

    Battery storage is one of the most effective ways to solve intermittency, it just happens to be incredibly resource-intensive.

    I don't think the incentives are aligned correctly for the "paying industry" idea to work all that effectively. Smart grids is a bit of a question-mark, that's a massive infrastructure project and people get pretty upset when their lights suddenly turn off - protesting and London riots upset.

    If you decided that it's too hard and you'll have to oversupply energy instead of storing it, that damages grid infrastructure. The prosperity we have in the Western world is a function of Engineering genius and the low-entropy and self-stored nature of coal and other fossil fuels.

    Vehicles as batteries idea depends on the numbers, what assumptions are you making to make that idea work?

    Do you have any particular examples? And why does this matter? If you're particularly enlightened, then please share what you know

    This is conjecture, you have hardly provided any numbers on power/unit-land. The actual numbers coming from the Mojave desert is something like 5W/m2 - you would need to be incredibly invasive with your solar panels to produce anywhere near enough energy for a population.

    The average US/European lifestyle demands something in the order of 125kWh/day - a thousand square meters of land per person. If you take into account things like overunity water/air-source heat pumps and high efficiency vehicles, it would save a meager 30-40%.

    It might be possible for us, even with massive technological difficulty, but for the developing world that doesn't really care about global emissions and only care about energy security (a lack thereof -> a case of deadness) they'd continue with their use of fossil fuels.



    It doesn't seem to me that you've actually run any numbers - the issues go far beyond "the energy lobby". The technological hurdles, land-invasiveness, etc are fundamental challenges to PV technology. It would be relatively sensible to consider deploying in Sub Saharan Africa that get 3x the solar flux than a country like the UK.

    Biomass doesn't produce much more than 0.2 watts per square meter, but at least it's low entropy.
    Most of the data I am using is from lectures that I've attended at the Oxford Martin School, I do not have them off the top of my head but you are very welcome to watch them (Eyre & McCulloch in particular which if I recall correctly covers rather concisely most of what I wrote about above including alternative energy infrastructures and alternatives to silicon-based cells as well as plenty of quantitative evidence supporting the feasability of a PV-powered world, Kammen's talk is also very good. I realise that this might seem like a bit of a cop-out trying to get you to watch these lectures rather than relying on me for an answer which may be correct to some extent but they are genuinely excellent talks and Eyre & McCulloch's talk in particular converted me from being pro-nuclear to being highly skeptical of nuclear energy so I would really strongly encourage you as a future nuclear engineer to watch it. I'd rather you get your information from a reliable primary source than a non-specialist like myself). Needless to say, all I'm doing is regurgitating the cutting edge research that economists and scientists are doing on the feasibility of large-take uptake of PVs.

    To address a few of your points though. It's pretty undeniable that the rate at which the cost of PV technology is decreasing vastly exceeds the potential of nuclear energy. Modular and molten salt reactors, if the nuclear industry had managed to bring them onto the market already, would have been highly successful and probably would have delayed any "renewable energy revolution" by a long time because it's an excellent idea. The problem is that, for various reasons, this hasn't happened and whilst significant improvements in things like safety have been made, the nuclear industry as a whole has failed to properly exploit these fascinating alternatives and by the time they're ever brought to the mass market, if ever, their window of opportunity will probably have passed. I'd be happy to be proven wrong here since I think modular nuclear reactors are a great idea and I've been to some very enthusiastic talks by proponents but I don't really get the feeling that it's going to happen. To be clear, I'm not predicting the death of the nuclear industry, but I am arguing that renewable energy could out-compete nuclear energy as the primary energy source for the world over the next 50-100 years. Again, with the major caveat is that this can only happen if there's the political will, which I'm not sure there will be.

    Another key issue I've got with your reply is the claim that this technology is less attractive for developing countries which I don't think could be more wrong. The major challenge for developed countries over the next few decades, assuming we're interested in a "clean energy revolution", is implementing fundamental changes in the way our energy system operates which will be fiercely opposed because democracies and corporate economies do not like major economic changes. These challenges largely do not exist with developing countries who are building infrastructure from the ground-up. The other key benefit of solar PVs is that they are fundamentally decentralised so, whilst potentially being able to be integrated into a smart-grid in the future, can be installed without extensive energy infrastructure being required, and are low-maintenance. It is much, much easier to help people develop their own local energy grids based on low-voltage solar arrays than to plan gigantuan, top-down nuclear-based national grids.
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    The discussion about the nuclear industry not exploiting the alternative technologies properly is why I have to look outwards for inspiration - Her Majesty's Government won't feel forced to act until it becomes clear that renewable technologies are very difficult to implement on the scales demanded of the Paris and Copenhagen agreements.

    I've been more pro-renewables until I've really looked into the numbers from David MacKay's "Sustainable Energy - without the hot air" book that makes you really wonder whether a renewables-only world is fantasy. I'm sure renewables and nuclear will have to work together in tandem, but which direction will take the lead is anyone's guess.

    I would personally wager that for as long as nuclear energy doesn't play more than 30-50% of the energy supply, we will always see fossil fuels. I feel a good ratio that is more likely to work is about 65% nuclear, 30% renewables, and 5% fossil fuels.

    There is no economy I know of that has attempted to be 100% renewable, with exception of geographically idealised places (eg right next to a large waterfall to capture hydro, or geothermal sources). Germany is definitely not on the "100% renewables" list. 90% nuclear economies are not impossible, France is certainly nearing that target on dated technologies.

    The Governments that take their energy very seriously include China and India, simply because the former knows that even with its fossil fuels there'd be a massive energy gap and it really doesn't want to kill too many citizens with Beijing-pollutants. The Chinese government's investments make it clear that even though solar energy may provide some, it is not nearly sufficient for an energy intensive industrial economy so it invests heavily into nuclear projects and research.

    India is very interested in exploiting different nuclear fuels (Th-232), and China's keen on exploiting different coolants.

    A lot of places in Africa may use renewables, but it'll be unlikely to bring them up to a Western standard of living even if the cost is low - the energy we demand is absurdly high, the problem with delivering the quantity of energy demanded is quite an issue.
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    (Original post by Rather_Cynical)
    I've been more pro-renewables until I've really looked into the numbers from David MacKay's "Sustainable Energy - without the hot air" book that makes you really wonder whether a renewables-only world is fantasy. I'm sure renewables and nuclear will have to work together in tandem, but which direction will take the lead is anyone's guess.
    I've also read SEWTHA and you're absolutely right, it's outstanding and it's what made me pro-nuclear until relatively recently. Having attended many talks on energy from the "establishment" (i.e. Government and Industry) and from academia, there seem to be two fairly different attitudes towards the future of energy. The establishment narrative is very much built upon a steady-state idea, the idea that paradigm shifts in energy are not going to happen and that the institutions that dominate today are going to be the institutions that dominate tomorrow. If you have this mentality than a world dominated by nuclear is the obvious and rational prediction because it's by far the most comfortable option. It integrates seamlessly (more or less) with the existing energy infrastructure, it doesn't change the balance of power very much in terms of who owns the capital and it solve the environmental issues without kicking up too much of a fuss.

    The other attitude is one that I see much more in academia amongst scientists and academic economists who feel free to envision a radically and fundamentally different system which would ultimately be a better way of doing things. And I think they have a very good reason for thinking that these new systems would be fundamentally better, as is made clear in the lectures that I linked earlier. The problem is that these predictions are absolutely at odds with the "status quo" mentality and are absolutely unacceptable for anybody in the energy establishment because it essentially predicts the death of the system that supports their livelihood. I sort of see it like a thermodynamic process that results in a much more stable product, but with a high activation energy. I am absolutely prepared to accept that the "status quo" model is the more likely happen because the odds are stacked against an energy revolution. But I do maintain that a world powered by renewables in 2100 would be better than a world that isn't.

    And I should clarify that when I saw "powered by", I mean "as the main energy source". I'm not saying that everything should be 100% solar, that would be crazy. A 60/40 split between renewables and "improved" nuclear would be absolutely satisfactory in my view.
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    I think we're more or less on the same chapter, just different pages.

    I hold the view that by 2100, nuclear fusion would either have a) become incredibly successful at displacing almost all fossil fuels and have been (or is in the process of being) adopted by developed countries (developing countries lag behind a few decades using older technologies), b) proven to have excellent potential but the technological challenges were never fully resolved, c) proven the economics of it doesn't add up and we're going to have to put up with some form of fission/renewables split. I certainly hope that it's the first two options, rather than the lattermost option. I mean, there is nothing in the laws of physics that prevent us from exploiting fusion power, it's just really hard to do.

    I feel those numbers may depend where most of the human population is, the highest human population growth is in African countries where solar energy is plentiful so the split may tilt in your favour (60-70% is technologically possible). A large portion of the globe does still live in the Northern hemisphere at high latitudes, Europe is certainly not a good place to push for 60% renewables - 40 to 50% will already take massive efforts.

    The "status quo" mentality is unfortunately going to be a reality - roads were paved over paths, to unearth the soil and build anew ("paradigm shift") is a dangerous game that has reasonable potential to set us back decades should anything fail. I'd imagine any kind of responsible politician would not be willing to wager economies on the roulette wheel of chance.
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    (Original post by Rather_Cynical)
    I think we're more or less on the same chapter, just different pages.

    I hold the view that by 2100, nuclear fusion would either have become a) incredibly successful at displacing almost all fossil fuels and have been (or is in the process of being) adopted by developed countries and developing countries lag behind a few decades using older technologies, b) proven to have excellent potential but the technological challenges were never fully resolved, c) the economics of it doesn't add up and we're going to have to put up with some form of fission/renewables split. I certainly hope that it's the first two options, rather than the lattermost option. I mean, there is nothing in the laws of physics that prevent us from exploiting fusion power, it's just really hard to do.

    I feel those numbers may depend where most of the human population is, the highest human population growth is in African countries where solar energy is plentiful so the split may tilt in your favour (60-70% is technologically possible). A large portion of the globe does still live in the Northern hemisphere at high latitudes, Europe is certainly not a good place to push for 60% renewables - 40 to 50% will already take massive efforts.

    The "status quo" mentality is unfortunately going to be a reality - roads were paved over paths, to unearth the soil and build anew ("paradigm shift" is a dangerous game that has reasonable potential to set us back decades should anything fail. I'd imagine any kind of responsible politician would not be willing to wager economies on the roulette wheel of chance.
    The problem with nuclear fusion is that I think there's a good chance that your scenarios (b) and (c) will indeed be the case because so far the only people I've met who have a lot of faith in nuclear fusion are politicians and scientists and engineers with a vested interest in making optimistic projections about its viability. I'd be happy to be proven wrong - I think that there are certain key advantages of solar over fusion, most critically the decentralisation aspects which I think would be big social benefits, but I don't think these advantages are significant enough to make a fusion-powered world undesirable - but I'm still not optimistic about fusion becoming feasible any time soon.

    I do think that you're doing a bit of injustice to the feasibility of solar energy in Europe. Even at the relatively high latitudes you've got a good 102 W m-2 of solar energy incident to the earth which is ample, even if it's more effective at lower latitudes. As you're probably well aware, Germany has already managed to be powered 100% by renewables on a small number of days and whilst, yes of course these are not "normal" days so you've still got all of your issues with intermittency but the fact that this has been achieved with relatively little political effort shows that solar energy can power countries even at high lattitudes. The challenge isn't a lack of solar energy, the challenge is intermittency. As you're probably also aware (I think this was mentioned in SEWTHA too, actually) others have come up with the idea of putting large PV arrays in North Africa and paying them for extremely cheap energy to then channel to Europe although for obvious reasons, political and technical, this isn't going to happen any time soon.

    I'm a realist in that I'm not expecting this "solar energy revolution" to happen but I'm an optimist in that I think it would be great if it could happen, which is why I support it because if it's going to happen, optimism is strongly needed!
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    (Original post by Plagioclase)
    The problem with nuclear fusion is that I think there's a good chance that your scenarios (b) and (c) will indeed be the case because so far the only people I've met who have a lot of faith in nuclear fusion are politicians and scientists and engineers with a vested interest in making optimistic projections about its viability.
    I think this problem will be unavoidable, we are in competing industries here and there is also asymmetric information. It's only credible to speculate about nuclear fusion if you have a sufficient scientific background (unfortunately I'm not PhD educated yet, so neither have I) where the problem of vested interests pop up.

    I've addressed a few points in earlier responses to this thread, there are major material challenges to build large tokamak reactors having visited CCFE myself. Plasmas are terribly complex and it will take some genius to figure out some of the physics problems (losses) and engineering problems (material irradiation/breeding tritium/confinement times/ignition and the problems with overheating the superconducting magnets).

    It's better to discuss this post-ITER, if we get Q > 10 then we've got a good shot at fusion reactors generating electricity in 50 years (it's currently 0.65)

    (Original post by Plagioclase)
    I'd be happy to be proven wrong - I think that there are certain key advantages of solar over fusion, most critically the decentralisation aspects which I think would be big social benefits, but I don't think these advantages are significant enough to make a fusion-powered world undesirable - but I'm still not optimistic about fusion becoming feasible any time soon.
    I think that's why it's ideal to have a hybrid system, decentralisation gives a lot of power (excuse the pun) back to consumers and will be invaluable when faced with dire circumstances - in war and anarchy, centralised systems fail. But in peacetime, which an abundance of energy will help bring, centralised systems are more efficient.

    (Original post by Plagioclase)
    I do think that you're doing a bit of injustice to the feasibility of solar energy in Europe. Even at the relatively high latitudes you've got a good 102 W m-2 of solar energy incident to the earth which is ample, even if it's more effective at lower latitudes. As you're probably well aware, Germany has already managed to be powered 100% by renewables on a small number of days and whilst, yes of course these are not "normal" days so you've still got all of your issues with intermittency but the fact that this has been achieved with relatively little political effort shows that solar energy can power countries even at high lattitudes. The challenge isn't a lack of solar energy, the challenge is intermittency. As you're probably also aware (I think this was mentioned in SEWTHA too, actually) others have come up with the idea of putting large PV arrays in North Africa and paying them for extremely cheap energy to then channel to Europe although for obvious reasons, political and technical, this isn't going to happen any time soon.
    I think Germany does a good proof of concept that renewables can make a meaningful impact on energy production, it does not show that it will make a large enough impact that warrants the speculation that it could be the primary energy source. The German model with the France model will be the most probable outcome, but we need to address the political scares about Fukushima.

    (Original post by Plagioclase)
    I'm a realist in that I'm not expecting this "solar energy revolution" to happen but I'm an optimist in that I think it would be great if it could happen, which is why I support it because if it's going to happen, optimism is strongly needed!
    I'll put a small wager on a solar revolution, some ideas like concentrated solar and quantum dots and such are interesting, but the massive growth in energy demand in the near future (electrification of vehicles and heating) makes me feel that solar won't cut it at latitudes that get less than 200Wm-2.

    The energy demand per person now limits us to a certain standard of living, and no democratic country has ever said "we're quite happy with economic/social regression". The only countries that have in the past that I can think with ideas remotely close involve authoritarian regimes that didn't care very much about its citizens - Chairman Mao's Great Leap Forward and Gaddafi's poor trade relationships.
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    NB - the promise of energy abundance solves a lot of humanitarian crises - if we hit peak water, reverse osmosis can turn the sea into a massive river, and if we ever use up the ore of this earth, then we can turn landfills into ore mines using energy-intensive forms of recycling. I would like to imagine a world in a hundred years that uses ten times or a hundred times as much energy as we do today.

    In this utopian world, economics can flip itself over and there is potential for post-scarcity, if you reject the conventional notion of economics that humans have infinite wants/needs. Those kinds of worlds would be less likely to engage in conflict over resources, since there is plenty. AI and automation would have to play a role, but perhaps we can be freed of the slavery/monotony of work and pursue goals beyond material possession.

    I feel nuclear fusion and highly advanced automation technologies could bring us fairly close to that ideal - that's the kind of society where there is true freedom.
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    http://phys.org/news/2016-07-breakth...es-carbon.html

    This is something that can compete with nuclear. PV is pretty awful unless you're near the equator.
 
 
 
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