Potential Consequences of Large-Scale Earth Hour Participation

[vanesch]

Of course some people will go overboard with it (the facebook group comes to mind), but as an engineer and a person who pays power bills, the idea of energy efficiency is very appealing to me, so I support anything that will lead to awareness for the need to reduce the amount of wasted energy. I'm not going to change my life in the name of conservation, but I'll do all the little things like use energy efficient versions of things I use.

The question is: why ? It is of course always good engineering to do the thing with a minimum of resources, if that's what you mean: minimum amount of material, minimum amount of waste, minimum amount of consumption, minimum amount of production time... That's simply good engineering. But apart from that, which I think is in any case being done, what's the problem with energy consumption ? The problem resides with environmentally unfriendly ways of energy production, eventually. Not with the consumption.

I think it is 100 times better to have environmentally friendly ways of generating power, and then consume lots of it, than to have environmentally bad ways of producing them, and then trying to consume 10% less.

My personal conviction is that it is a green ideology thing that "people have to do efforts" (flagellate themselves or something) in order to get impregnated by their ideology. Finding a technical solution won't do. It's not evangelical enough.

 

[Einstienear]

I took part of it.

As I do live in Sydney, I could not be more happy to contribute to this.

There were no side-effects, and we went on with our normal physics lives...

 

[Ivan Seeking]

The problem has been that environmentally friendly options are barely or not competitive both financially, and also if we consider the dust to dust energy benefit. Until we have a viable selection of more competitive options, conservation is the best way to have an immediate effect. The goal is to have a virtually inexhaustible supply of environmentally friendly energy, but the reality is that we don't have one yet.

For example, until recent years solar cells likely barely paid off. They were essentially petroleum energy batteries that paid off very slowly. In the end, one was lucky to break even over a twenty year span, which also happened to be the life of the panels. This may even suggest that the net energy [dust to dust] gain over the life of the panels was zero! They are getting better, but when one considers the economic cost vs the benefit, they still can't be justified in many areas of the US. Breakthrough technologies like the solar panels on the Mars rovers are exciting, but for now they cost something like $30,000 for a few small panels...and that high cost is suggestive of a high energy demand for production, so one has to wonder about the dust to dust benefit - to what extent are they petroleum energy batteries? Or even in the case of off-the-shelf technology, how much coal was burned in China, petro consumed in mining and smelting operations, petro used for transporting the raw materials and other processing, coal for lighting for factories, gasoline for commuting workers, etc, in order to make them? And then we need to consider incidental environmental damage as well.

 

[Ivan Seeking]

A few more thoughts on Negawatts: By reducing demand we not only save energy, we also help to delay the need to build additional power plants or to install or upgrade power lines and transformers. We also save the energy lost in power transmission. Typically this is between six and ten percent, but the savings can be higher during periods of heavy demand since alternative and less efficient transmissions paths are often used in order to meet the demand. Not to mention that the losses go as I²R, so additional loads [esp during heavy loads] result in even greater losses overall than a given load would generate on its own.

 

[vanesch]

The problem has been that environmentally friendly options are barely or not competitive both financially, and also if we consider the dust to dust energy benefit.

I know I sound like a broken record, but the most competitive form of electricity production is also a very ecological one. It is the second ecological one, after hydro power, and it is nuclear power, and yes, in that price is comprised the investment (the bulk of it! >90%), the fuel, and the waste management and decommissioning.
Ecologically-wise, nuclear comes second after hydro, and far before solar and wind (which are bad concerning their need for space, materials - concrete for wind and special materials for solar, and CO2 emissions). Economically, it is the most competitive form.

For example, until recent years solar cells likely barely paid off. They were essentially petroleum energy batteries that paid off very slowly. In the end, one was lucky to break even over a twenty year span, which also happened to be the life of the panels. This may even suggest that the net energy [dust to dust] gain over the life of the panels was zero! They are getting better, but when one considers the economic cost vs the benefit, they still can't be justified in many areas of the US. Breakthrough technologies like the solar panels on the Mars rovers are exciting, but for now they cost something like $30,000 for a few small panels...and that high cost is suggestive of a high energy demand for production, so one has to wonder about the dust to dust benefit - to what extent are they petroleum energy batteries? Or even in the case of off-the-shelf technology, how much coal was burned in China, petro consumed in mining and smelting operations, petro used for transporting the raw materials and other processing, coal for lighting for factories, gasoline for commuting workers, etc, in order to make them? And then we need to consider incidental environmental damage as well.

Exactly. That's why, for the moment, solar and wind are NOT the most ecological ways of generating electricity. For solar, this might change one day, for wind, I doubt it as the technology is rather mature. The problem is that we've written off the technology that exists, that doesn't cause problems, and that is competitive, just for ideological reasons. And once we've done that, for the same ideological reasons, we now have to "consume less to save the planet".

The only power production that is still more ecological is hydro, and even there (3 gorges dam), one can sometimes have one's hesitations.

 

[Moonbear]

I'm still trying to figure out the point of this whole silly stunt. I mean, do you really think it would have any long-term effect on conservation? Most people know to not leave all the lights on in the house when they're only in one room, for example. Whether or not they do it, I don't think sitting in the dark for an hour was going to help change their behaviors. If anything, it could have had a completely opposite effect on some people...realize how BORED one would get sitting around in the dark with nothing electric on and decide they really do need electricity, and a lot of it, and aren't going to change a thing.

The other stupid thing is it encourages completely the opposite behavior of what leads to conservation, especially heading into the spring and summer months. We don't need to sit in the dark at night, especially the early evening on a weekend when people are still awake and active. That's the ideal time to be doing things like running the dishwasher or cooking or washing and drying clothes...the outside temperature is cooling, so if you do all that stuff during the evening hours, you don't need to work an air conditioner as hard in the summer to compensate for the extra heat given off by those appliances, and in winter, albeit miniscule, you'd ease up some of the heat needed by your furnace. (And, yep, that's what I was doing during that hour...running the dryer for the clothes I had washed a bit earlier in the day.)

It would make a lot more sense to turn out the lights during the daytime, when you can show people that they can find other things to do that don't rely on electricity consumption...open the blinds and let the light into read, send the kids outside to play, etc. That would have been a lesson to show people that hey, yeah, they can actually conserve energy without making huge sacrifices. Indeed, right now, it's a bright sunny day out, so I don't have a single light on in the house...there's no need for it with the blinds open.

All turning out the lights in the early evening shows is just how dependent we are on electricity...and that's not necessarily a bad thing. Afterall, the whole message about this Earth Hour nonsense was able to be spread because we have electricity...internet, news on television and radio, phones, etc.

 

[Schrodinger's Dog]

Having an enormous coast to land area ratio, wave and wind power work out as pretty cheap alternatives for us. People say the look ugly but to be fair I'd rather have a wind farm off the coast and a wave power generator or hydro plant on my tidal rivers, than the alternatives.

As for solar the future is looking bright:

They have managed to get solar cells up to 42.8% efficiency. In some areas it's actually starting to reach break even costs with hydrocarbon sources of power.


Source.

Last year, Allen Barnett and colleagues at the University of Delaware, Newark, set a new record with a design that achieved 42.8 per cent energy conversion efficiency. Barnett says 50 per cent efficiency on a commercial scale is now within reach. Such designs, married to modern manufacturing techniques, mean costs are falling fast too (see Diagram).

As a result, in parts of Japan, California and Italy, where the retail price of electricity is among the world's highest, the cost of solar-generated electricity is now close to, and in some cases matches, that of electricity generated from natural gas and nuclear power, says Michael Rogol, a solar industry analyst with Photon Consulting, based in Aachen, Germany. For example, in the US the average price of conventionally generated electricity is around 10 cents per kilowatt-hour. The cost of solar-generated electricity has fallen to roughly double that. This has created a booming market for PV cells - now growing by around 35 per cent annually - and private investors are starting to take a serious interest. The value of stocks in companies whose business focuses primarily on solar power has grown from $40 billion in January 2006 to more than $140 billion today, making solar power the fastest-growing sector in the global marketplace.
“In some places, the cost of solar-generated electricity is close to that of electricity from conventional sources”

George W. Bush has acknowledged this new dawn, setting aside $168 million of federal funds for the Solar America Initiative, a research programme that aims to make the cost of PV technology competitive with other energy technologies in the US by 2015. Rogol thinks Bush's target is achievable. He says the cost of manufacturing PV equipment has fallen to the point where, in some places, PV-generated electricity could already be produced for less than conventional electricity. Manufacture PV cells at $1 per watt of generating capacity and the cost should be competitive everywhere.

And.

http://technology.newscientist.com/...-invention-special-longlife-solar-cells.html"

Long-life solar cells

Polymer solar cells used to convert sunlight to electricity are degraded by ultraviolet light, which limits their lifespan.

Yang Yang, a materials scientist at the University of California, Los Angeles, US, has a simple solution. He suggests coating the solar cell with a material that converts ultraviolet photons into ones of visible light.

The new "photon conversion material" (PCM) converts harmful UV into longer wavelengths, enhancing efficiency of solar-energy conversion and reducing damage to cells. This should help the solar cells last longer, as well as increase their electrical yield.

The PCM could be made of a liquid, a gel, nanoparticles or a solid, the researchers say. In experiments, they added the polymer blue polyfluorene to solar cells and found that it did indeed reduce the damage caused by UV light.

Read the full plastic solar cell patent application

 

[Gokul43201]

I'm still trying to figure out the point of this whole silly stunt. I mean, do you really think it would have any long-term effect on conservation? Most people know to not leave all the lights on in the house when they're only in one room, for example. Whether or not they do it, I don't think sitting in the dark for an hour was going to help change their behaviors. If anything, it could have had a completely opposite effect on some people...realize how BORED one would get sitting around in the dark with nothing electric on and decide they really do need electricity, and a lot of it, and aren't going to change a thing.

I think the participants are likely going to be the ones that are already very aware of their energy consumption patterns and care about conserving power. The point of the exercise may be to get the others to notice that there's something going on and spark a dialog.

The other stupid thing is it encourages completely the opposite behavior of what leads to conservation, especially heading into the spring and summer months. We don't need to sit in the dark at night, especially the early evening on a weekend when people are still awake and active. That's the ideal time to be doing things like running the dishwasher or cooking or washing and drying clothes...the outside temperature is cooling, so if you do all that stuff during the evening hours, you don't need to work an air conditioner as hard in the summer to compensate for the extra heat given off by those appliances, and in winter, albeit miniscule, you'd ease up some of the heat needed by your furnace. (And, yep, that's what I was doing during that hour...running the dryer for the clothes I had washed a bit earlier in the day.)

It would make a lot more sense to turn out the lights during the daytime, when you can show people that they can find other things to do that don't rely on electricity consumption...open the blinds and let the light into read, send the kids outside to play, etc. That would have been a lesson to show people that hey, yeah, they can actually conserve energy without making huge sacrifices. Indeed, right now, it's a bright sunny day out, so I don't have a single light on in the house...there's no need for it with the blinds open.

1. Only in the US, in my experience, do people rely heavily on lights during the daytime. Besides, turning off lights during the daytime has no visual effect - it's like putting up an advertising hoarding printed in invisible ink. Again, the point here is not to sell the idea of conservation to people that will participate in EH, but to their neighbors, visitors or other passersby.
2. This idea, if I'm not mistaken, was initiated in Sydney, which is heading into winter.

 

[Moonbear]

Again, the point here is not to sell the idea of conservation to people that will participate in EH, but to their neighbors, visitors or other passersby.

Who probably just think it means you're not home. Would you notice if your neighbors had their lights out on a Saturday night? I sure wouldn't. Maybe it helped confuse a few would-be burglars to have dark houses while the people are still home, but I don't think anyone else but burglars and the neighborhood busy body would pay attention to whether or not someone's house had their lights on or off, especially on a night when a lot of people are usually out for the evening.

 

[DaveC426913]

Im turning on all the lights in my house for Earth hour, just because I think the entire Earth hour notion is STUPID.

Yah, I got a 25 year old who has the same rebellion complex.

 

[Moonbear]

Yah, I got a 25 year old who has the same rebellion complex.

I haven't grown out of it yet either. I didn't do it, but it sure was tempting...sometimes you just have to protest the protesters.

 

[Gokul43201]

Who probably just think it means you're not home. Would you notice if your neighbors had their lights out on a Saturday night? I sure wouldn't. Maybe it helped confuse a few would-be burglars to have dark houses while the people are still home, but I don't think anyone else but burglars and the neighborhood busy body would pay attention to whether or not someone's house had their lights on or off, especially on a night when a lot of people are usually out for the evening.

I guess you'd notice if you're driving around and more lights appeared to be off than usual, but that would take some significant fraction of the population to participate - not very likely in most places outside Aus/NZ.

 

[Schrodinger's Dog]

I haven't grown out of it yet either. I didn't do it, but it sure was tempting...sometimes you just have to protest the protesters.

Yes it's a sort of "fight the lack of power" thing. Which neatly analogises the situation and enables me to make a very weak joke at the same time.

 

[Cyrus]

If those people lack the brain capacity to see that turning off your lights for an hour won't do anything, I seriously doubt they can make any other rational decisions when it comes to energy policy. There just a bunch of wacked out hippies who want a cause and its something they can easily do for an hour to feel like they 'did something', when in fact they did absolutely nothing.

How about they take the bus/metro/walk for a week?

 

[glondor]

It was those same whacked out hippie types that put us in this mess to begin with,The pressure on the nuclear industry from enviroweenies pretty much killed the hopes of new nuclear plants for years. Now all sectors are pushed with shortages we are back looking at nuclear as the only option but it will take hundreds of billions and decades in North America alone to get clean power back up to speed. Blackouts are not your friend! I guess the enviroweenies pretty much killed hydro development for the last 20 years as well. jmho

 

[Ivan Seeking]

I know I sound like a broken record, but the most competitive form of electricity production is also a very ecological one. It is the second ecological one, after hydro power, and it is nuclear power, and yes, in that price is comprised the investment (the bulk of it! >90%), the fuel, and the waste management and decommissioning.

The problems that I see with nuclear power are that first, we live in an age of terrorism where the proliferation of nuclear materials is unwise. Next, there is no perfect system, so security at nuclear facilities will eventually be compromised. The more reactors that we have, the sooner and more frequent will be the security or controls violations. Also, whether or not the reactors themselves are or can be made failsafe, most people will not believe or accept this claim. Which brings us to the most significant reason why nuclear power will not be the solution to our energy needs: We couldn't possibly build the plants quickly enough for the contribution to be significant in the immediate future. Given the long life of these projects, the complexities and political difficulties in finding acceptable locations, and the rate at which the price of energy makes alternatives more and more practical and viable, nuclear will never be the solution.

For the record, I don't trust that this industry can be properly regulated. I know too much about how real systems work to fall for that one! There is too much at stake.

 

[Ivan Seeking]

There is also the notion that for security sake, we want to decentralize the energy networks. Having entire cities dependent on one large vulnerable source of energy is unwise. This means that large nuclear reactors and large dams are poor choices for an energy supply.

As for the Earth hour thing, consciousness raising is good, but it's a dumb way to do it.

 

[Schrodinger's Dog]

It was those same whacked out hippie types that put us in this mess to begin with,The pressure on the nuclear industry from enviroweenies pretty much killed the hopes of new nuclear plants for years. Now all sectors are pushed with shortages we are back looking at nuclear as the only option but it will take hundreds of billions and decades in North America alone to get clean power back up to speed. Blackouts are not your friend! I guess the enviroweenies pretty much killed hydro development for the last 20 years as well. jmho

Nuclear power is not renewable anyway, at least fissionable power, it's probably a good thing in the long run, it makes future more renewable technologies more of an imperative. As for hydro power, I don't see how they killed it? It's big business here, ok it's wave power and tidal power, but it's still on the drawing board. In fact our first tidal power power plant goes on line soon.

I agree that it's a dumb idea, but since a lot of people appear quite dumb I'm not sure it's going to do that much damage, other than making some people more aware.

 

[Cyrus]

Maybe I am missing something here, but the green movement started in the 70s. Whose conscious is this going to raise: that of a retard who never bothered to read a newspaper or watch the nightly news in the past 30 years?

 

[Schrodinger's Dog]

Maybe I am missing something here, but the green movement started in the 70s. Whose conscious is this going to raise: that of a retard?

Yes even retards need reminding of the value of energy efficiency, not everyone is a non retard.

 

[Cyrus]

The problems that I see with nuclear power are that first, we live in an age of terrorism where the proliferation of nuclear materials is unwise. Next, there is no perfect system, so security at nuclear facilities will eventually be compromised. The more reactors that we have, the sooner and more frequent will be the security or controls violations. Also, whether or not the reactors themselves are or can be made failsafe, most people will not believe or accept this claim. Which brings us to the most significant reason why nuclear power will not be the solution to our energy needs: We couldn't possibly build the plants quickly enough for the contribution to be significant in the immediate future. Given the long life of these projects, the complexities and political difficulties in finding acceptable locations, and the rate at which the price of energy makes alternatives more and more practical and viable, nuclear will never be the solution.

For the record, I don't trust that this industry can be properly regulated. I know too much about how real systems work to fall for that one! There is too much at stake.

Good job hippies! You killed nuclear energy, and now your trying to save the planet by using clean energy. I say we burn these people for energy.

 

[Cyrus]

Yes even retards need reminding of the value of energy efficiency, not everyone is a non retard.

Considering they are stupid enough to buy into Earth hour, I think they need reminding in a smart educated way. Not a moronic way.

We should just tax the stupid so they can't afford to use energy. Problem solved.

 

[jhicks]

Maybe I am missing something here, but the green movement started in the 70s. Whose conscious is this going to raise: that of a retard who never bothered to read a newspaper or watch the nightly news?

Nice straw man argument. Of course everyone knows about the green movement. What people DON'T know generally are the figures. For example, I didn't know until a couple years ago about government studies that claim that electronics in standby may contribute into the double digits to our power consumption. Quantitatively, people are very much in the dark.

 

[Cyrus]

Nice straw man argument. Of course everyone knows about the green movement. What people DON'T know generally are the figures. For example, I didn't know until a couple years ago about government studies that claim that electronics in standby may contribute into the double digits to our power consumption. Quantitatively, people are very much in the dark.

What does that have to do with turning your lights off for an hour? I didnt know Earth hour was about giving figures on what power is being used by what. They must have missed the flyers on that one? So you got information a couple years ago, that has what to do with Earth hour?

 

[Schrodinger's Dog]

Good job hippies! You killed nuclear energy, and now your trying to save the planet by using clean energy. I say we burn these people for energy.

The human body gives off too many hydrocarbons when burnt, in fact it's better to bury these people and hope that the "gasses" they produce out of their bodies can be contained at a later date. Much as I am in favour of large Viking funerals, it seems that it is not the environmentally friendly alternative to stupidity.

I'd like to see study of how many people hydrocarbon energy producers kill as opposed to how many people would be killed by terrorists striking nuclear facilities. I think it might be far less than the fossil fuel system.

Considering they are stupid enough to buy into Earth hour, I think they need reminding in a smart educated way. Not a moronic way.

We should just tax the stupid so they can't afford to use energy. Problem solved.

We already have a stupid tax in this country it's called the lottery.

It's a similar lottery that idiots buy into about power needs. But this one actually funds the government in taxes.

 

[Cyrus]

Ok fine, let's send them to live in a hut in africa, where the only pollution they give off will be from their farts.

 

[Moonbear]

Nice straw man argument. Of course everyone knows about the green movement. What people DON'T know generally are the figures. For example, I didn't know until a couple years ago about government studies that claim that electronics in standby may contribute into the double digits to our power consumption. Quantitatively, people are very much in the dark.

What does that have to do with turning your lights off for an hour? I didnt know Earth hour was about giving figures on what power is being used by what. They must have missed the flyers on that one? So you got information a couple years ago, that has what to do with Earth hour?

I agree with Cyrus here. Nothing about Earth Hour educated anyone about REAL ways they can conserve energy (definitely nothing in all the news reports about not leaving computers in standby mode). All anyone talked about was turning lights out for an hour to raise awareness, but nobody provided anything for them to actually be aware of.

 

[DaveC426913]

If those people lack the brain capacity to see that turning off your lights for an hour won't do anything, I seriously doubt they can make any other rational decisions when it comes to energy policy. There just a bunch of wacked out hippies who want a cause and its something they can easily do for an hour to feel like they 'did something', when in fact they did absolutely nothing.

How about inspiring their kids? The kids don't know it was just a stunt.

 

[Cyrus]

Nothing like giving kids bad information, eh!?

A whole new generation of brainwashed hippies. Not only will they turn off the lights, they will think competition is a bad thing because in life, everyone is a winner! Hooray!

How about giving them actual honest to goodness information?

 

[vanesch]

The problems that I see with nuclear power are that first, we live in an age of terrorism where the proliferation of nuclear materials is unwise.

I didn't know we lived in "an age of terrorism"! I thought it was only a few scaremongers that used to say so in order to accomplish their agenda. But in any case this claim (one of the famous anti-nuclear activist lies ; the other three are: it's dangerous, there's no fuel left, and we don't know what to do with the waste) is wrong: it is much more difficult to make a nuke by *stealing* fuel from a power plant than to make one all by oneself, for many reasons. As to "dirty bombs" there is already enough radioactive material around to make some.
I think there has been done much more terrorism with chemical explosives than with nuclear material, but that has never inspired people to stop the whole chemical industry. Also, the most spectacular terrorist attack has been done with airplanes. Have we stopped using airplanes now ?

So if the argument "terrorists could use it" has any meaning, then we should stop all airplanes, stop all chemical processing, ... stop all the technical means that have already proven to be misused by terrorists, before stopping technology that has never been used by terrorists.

Next, there is no perfect system, so security at nuclear facilities will eventually be compromised. The more reactors that we have, the sooner and more frequent will be the security or controls violations.

Sure. Point is, we start from very very low. All this is fear mongering.

Also, whether or not the reactors themselves are or can be made failsafe, most people will not believe or accept this claim.

This is indeed the main difficulty: so many lies have been told for so long a time concerning nuclear power, that people now prefer to cause real ecological disasters and cling to their false beliefs, rather than accept that they've been told fairy tales and take on a real solution.

Which brings us to the most significant reason why nuclear power will not be the solution to our energy needs: We couldn't possibly build the plants quickly enough for the contribution to be significant in the immediate future. Given the long life of these projects, the complexities and political difficulties in finding acceptable locations, and the rate at which the price of energy makes alternatives more and more practical and viable, nuclear will never be the solution.

I don't think so. France switched to full nuclear in about 20 years time, 30 years ago. So this should be entirely possible right now. As to the costs, the Iraq war has cost the US in about 5 years the price of about 500 new nuclear power plants, which would have converted the US into full nuclear concerning electricity production (the US has now about 100 (old) nukes which produce about 20% of the electricity). Of course the industry would have had needed a bit more time to produce them.

Concerning alternatives, I am not against them, only, they are, for the moment, REAL fairy tales. The day that they are serious competitors, and can produce electricity in large quantities at competitive prices, I'm all for it - but then "reducing electricity consumption to save wind or sunshine" wouldn't make any sense either. So, or these alternatives are serious, in the near future (I don't think so, in the *near* future) and then there's no reason to reduce consumption, or they aren't and then we shouldn't take them seriously. Because in that case, the problem with taking them seriously, like Germany, is that at a certain point, you are confronted with reality, and you NEED electricity. So you quickly build coal power plants, as did the Germans. 27 of them.

The only country that was serious about it and achieved something, Denmark, really tried very hard for the past 20 years, and, with a lot of difficulties, they arrive at about 16-20% production by wind energy and a little help from their neighbors catching up all the irregularities. And then, Denmark is about ideally placed with their offshore windparks.

So, compare: France: 1976-1996: 20 years, from about 1% nuclear to about 80% nuclear, and helps half or Europe with it.
Denmark: 1986 - 2006: 20 years, from about 0% wind to about 16% wind, and a lot of difficulties.

What's the real solution here ?

For the record, I don't trust that this industry can be properly regulated. I know too much about how real systems work to fall for that one! There is too much at stake.

I don't think so. First of all, the nuclear industry knows how ticklish people are concerning nuclear, so they know that if they have one major failure, then that puts in doubt their entire sector.

But second, one should stop thinking of a failing power plant as a doomsday machine. Even a failing power plant with a major release of radioactive stuff is not worse than any other regional problem, and has, in the long run, not more effects than things we accept every day, like car accidents, pollution from conventional power plants, from traffic,...

In short, we HAVE a known technology that can solve cleanly for the next few centuries our energy problems without causing major (global) ecological problems, at a competitive rate, and for ideological reasons, and because of unproven phantasms spread by fear mongers, we refuse to use it, and go whining in our corner about how we don't know how to generate power without pollution, and we should all deprive ourselves from this and that, and reduce our consumption with 5 or 10%. This, to me, is silly irrational behavior with a dangerous side to it.

 

[Cyrus]

vanesch, what is proposed in terms of nuclear waste disposal, and how long does it take before it becomes at a 'safe' level?

Funny thing, I actually flew past three mile island last week on my flight to PA.

Can we put those barrels of nuclear waste in some hippies homes?

 

[vanesch]

vanesch, what is proposed in terms of nuclear waste disposal, and how long does it take before it becomes at a 'safe' level?

The standard solution (already studied by now for more than 20 years) is deep geological disposal (at depths from 200 - 700 meters underground). The idea is that the confinement of the geological layers is going to last for millions of years, but one studies eventual transport mechanisms that could bring some of the material to the biosphere before decay. Of course, you need to study carefully the geology and all the chemistry that goes with it, but there's by now a large body of knowledge on all this.

There are different "time scales" in nuclear waste, because of the different decay times of the different components. Also, the waste depends upon the kind of reactor we use. For the moment, we use "reactors with thermal spectrum" but "fast reactors" are the future.

I'll give you the numbers for a typical PWR. (pressured water reactor)
When used fuel is removed it is highly radioactive, because there are a lot of short-lived, highly active fission products. It is so active that it needs even some cooling or it gets hot. So the best thing to do is to keep it for a few years (typically 4 years) in a pool.

After that period, the activity has lowered quite a lot, and the material becomes more easily manageable (although still extremely radioactive).
After that, you can do several things. You can "can" it as "waste" (the open cycle). Or you can reprocess it, because only about 5% of enriched fuel has actually been "burned".

One considers that a component has become "safe" when it reaches the radiotoxicity level of the original uranium ore. That's a definition like any other, but it gives good orders of magnitude.

The spend fuel consists of 3 kinds of material:
- the fission products, the actual "ashes": they are by far the most active, but they decay fast: after about 300 - 400 years, this (essential) part is "safe".

- the minor actinides (americium, neptunium,...): unwanted side effects of a thermal spectrum: they are produced in small quantities, but they remain active on a scale of about 10 000 years, then they are "safe".

- the plutonium: partly unwanted, partly "new fuel", it is the nastiest component in the waste, and becomes "safe" only after 100 000 years.

Now, fuel reprocessing will take out the plutonium (that's what is done now) to re-use it as fuel. One COULD take out the minor actinides too, but doesn't know what to do with it for the moment, so one doesn't.

So as of now, unreprocessed fuel needs storage for at least 100 000 years, while reprocessed fuel from a thermal spectrum will only need 10 000 years.

However, in a fast reactor (which doesn't generate much, and can even burn, minor actinides), and can burn on plutonium, after reprocessing, the only thing that will remain is essentially the fission products. So there, the storage time needed is only 300-400 years. One can reprocess and reuse all of the plutonium, and the eventual small quantity of minor actinides, as fuel.

Reprocessed waste takes on the form of a solid solution in glass, put in a stainless steel container, of which the survival is estimated to be longer than 1000 years. In geological disposal, this means that the fission products don't matter, but that the actinides and the plutonium migration needs to be studied. However, it really seems that these things don't migrate a lot in the right geological layers. So even a dissolved container and glass wouldn't give a problem in the long run.

In the mean time, until permission is granted to do such actual disposal, the canisters are kept in temporary storage sites, where they can stay as long as one likes. In fact, the longer we keep them, the less active they are, and the closer we can pack them in the repository. So one usually thinks of keeping them 50 years (or longer) before putting them underground.

So:
- unprocessed fuel (still full of burnable material - so a real waste): 100 000 years
- reprocessed fuel from thermal power plant: 10 000 years
- reprocessed fuel from thermal power plant or from fast reactors, with removal of minor actinides, which can burn in fast reactors: 300 - 400 years.

After that, the waste is not "dangerous" anymore. Now, of course it is continuous decay: even after 200 years, the fission products are not very active anymore.

ANY of these schemes work out all right in deep storage. But of course, the shorter the needed period, the more sure we are of the predictions that nothing will go wrong.

 

[Moonbear]

vanesch, what is proposed in terms of nuclear waste disposal, and how long does it take before it becomes at a 'safe' level?

Considering what problems we have in this state with mine subsidence (collapsing of old coal mines), filling them up to stabilize the ground above them might be a win-win situation. The pollution from the coal dust coming out of those mines is a more real health hazard than burying radioactive waste that deep below the ground.

 

[DaveC426913]

This thread seems to have drifted.

 

[Cyrus]

Yeah, were actually talking about things that could make a difference instead of hippie nonsense. Whew close one!

Quick turn off your lights! Together, we can change! If only they left their lights on, they might have had a bright idea.

http://www.usmm.net/p/lightsout.jpg

Actually, this thread is exactly on topic. This kind of nonsense is a direct side effect of stunts like Earth hour.