What Is the Most Efficient and Safest Method to Generate Electricity?

[russ_watters]

So, you're saying that currently only 5 TW of the 15 TW consumed is in the form of electrical energy

Consumed for electrical energy: The 5 TW of consumed nuclear fuel (per hour) is converted to about 2.3 TW of electricity.

And were we to do the whole 15 as electrical energy, we would only have to generate 1/3 of the remaining 10, about 3.333 TW, instead of the whole 10. Am I understanding you correctly?

It probably isn't quite that low because not all of the other energy used is used for transportation or low temperature heating. Transportation is about 25% of the total (3.8 TW) and I'm going to guess that low temperature heating applications that could use heat pumps are another 25%. That means 1/3 of 7.6 = 2.5 TW. That leaves 15-7.6-5=2.4 TW unaccounted for and let's assume that's high temperature heat. So the total generated electricity to be an all-electric world would be about 2.3+2.5+2.4 = 7.2 TW.

You have any estimate of how much of the 15 TW is used by planes and ships? I'm curious.

According to the wiki, 20% of the total is transportation. I'll take a stab at it and say planes and ships are probably 10% of transportation, or 0.3 TW.

 

[russ_watters]

It would be quite a challenge to switch to all electric, cars and trains not so much but airplanes and ships would be difficult. Of course they could be replaced overtime, reintroduce the airship and build far greater continental train networks (like China's proposed new Silk Road that could connect it all the way to Europe with freight train links). We could even build a 21st century version of the NS Savannah and try to get commercial nuclear shipping back on the agenda.

If we reaaaaly want to go as nuclear/electric as possible, I think a great many big ships could be nuclear powered. Airplanes, though, are going to be a big problem.

 

[zoobyshoe]

Consumed for electrical energy: The 5 TW of consumed nuclear fuel (per hour) is converted to about 2.3 TW of electricity.

Ah, O.K.

It probably isn't quite that low because not all of the other energy used is used for transportation or low temperature heating. Transportation is about 25% of the total (3.8 TW) and I'm going to guess that low temperature heating applications that could use heat pumps are another 25%. That means 1/3 of 7.6 = 2.5 TW. That leaves 15-7.6-5=2.4 TW unaccounted for and let's assume that's high temperature heat. So the total generated electricity to be an all-electric world would be about 2.3+2.5+2.4 = 7.2 TW.

Sticking just to how many TW of nuclear fuel will be consumed, what would that figure be after conversion to an all-electric world? Your original statement was that it won't be one-to-one because electric cars and heat pumps are more efficient. So, I'm looking for your estimate of the reduced consumed TW.

 

[russ_watters]

Sticking just to how many TW of nuclear fuel will be consumed, what would that figure be after conversion to an all-electric world? Your original statement was that it won't be one-to-one because electric cars and heat pumps are more efficient. So, I'm looking for your estimate of the reduced consumed TW.

Nuclear power is about 30% efficient, so an all-electric world of 7.2 TW requires an input of about 22 TW of nuclear fuel.

 

[tom aaron]

If we reaaaaly want to go as nuclear/electric as possible, I think a great many big ships could be nuclear powered. Airplanes, though, are going to be a big problem.

Cimmercial nuclear ships are not being built and will not be built for some time. They are not viable economically or practically.

 

[zoobyshoe]

Nuclear power is about 30% efficient, so an all-electric world of 7.2 TW requires an input of about 22 TW of nuclear fuel.

I'm very confused. I thought you started with 15 TW to get to the 7.2 TW. Working backward, it doesn't seem you could get greater than 15 TW and it should be less with your previously proposed savings by electric car and heat pump.

 

[russ_watters]

I'm very confused. I thought you started with 15 TW to get to the 7.2 TW. Working backward, it doesn't seem you could get greater than 15 TW and it should be less with your previously proposed savings by electric car and heat pump.

The author of the article mixed together input and output (primary and secondary) and I guess I haven't untangled it enough for you yet: He said you'd need 15 TW of output (which would be 45 TW of input), but based on current usage you need 7.2 TW of output (22 TW of input).

In other words, he said you'd need 15,000 nuclear reactors (at 45 GW input to get 15 GW output) but you'd really need only 7,200 reactors (22 GW input, 7.2 GW output).

 

[zoobyshoe]

The author of the article mixed together input and output (primary and secondary) and I guess I haven't untangled it enough for you yet: He said you'd need 15 TW of output (which would be 45 TW of input), but based on current usage you need 7.2 TW of output (22 TW of input).

In other words, he said you'd need 15,000 nuclear reactors (at 45 GW input to get 15 GW output) but you'd really need only 7,200 reactors (22 GW input, 7.2 GW output).

Regardless of what he said I though you were starting with 15 TW of input to get 7.2 TW output. That's what is confusing me.

 

[russ_watters]

Regardless of what he said I though you were starting with 15 TW of input to get 7.2 TW output. That's what is confusing me.

Essentially yes: I calculated 7.2 TW of output from 15 TW of input, based on my efficiency and usage assumptions/data.

The world doesn't care much about the input. Indeed, for renewable sources we generally don't even consider the input at all, since it is free and eternal. The world cares about the output. What I did, that matters for his analysis, was correct his output number (for a start). The fact that the input number goes up as a result appears to be tripping you up, but it isn't really all that important. On a day-to-day basis, we really don't care much about the input of a nuclear plant.

 

[zoobyshoe]

Essentially yes: I calculated 7.2 TW of output from 15 TW of input, based on my efficiency and usage assumptions/data.

O.K. So what you're saying is that, in the switch from current power generation to all nuclear/electric, we would have to consume more than 15 TW to get the same 7.2 TW output. Consumption would be more like 22TW.

The world doesn't care much about the input. Indeed, for renewable sources we generally don't even consider the input at all, since it is free and eternal. The world cares about the output. What I did, that matters for his analysis, was correct his output number (for a start). The fact that the input number goes up as a result appears to be tripping you up, but it isn't really all that important. On a day-to-day basis, we really don't care much about the input of a nuclear plant.

But uranium is non-renewable, so it is important. This goes to his claim that, were we to be generating the current output exclusively by nuclear we'd use up all the viable uranium in 5 years. That was my original question: how long will supplies of nuclear fuels last? If he's overestimated consumption by a factor of 3, as you say, that means we actually would have 15 years of an all nuclear/electric world before the viable uranium got used up. Not better enough to be worth correcting him, IMO. "The world," as you put it, "doesn't care about" ten more years. The world is looking for the longest lasting possible energy source. Should we invest so much in something that's just going to be fossil fuels all over again?

 

[russ_watters]

O.K. So what you're saying is that, in the switch from current power generation to all nuclear/electric, we would have to consume more than 15 TW to get the same 7.2 TW output. Consumption would be more like 22TW.

Yes.

But uranium is non-renewable, so it is important.

We're still a very long way from getting to that issue, given all the other related problems in the paper. For example, can I keep the Hoover Dam or do we have to replace that with nuclear power too?

In any case, you still aren't hearing me on why the thermal energy input itsn't important to the discussion. It will become more apparent at the end of this post.**

This goes to his claim that, were we to be generating the current output exclusively by nuclear we'd use up all the viable uranium in 5 years. That was my original question: how long will supplies of nuclear fuels last? If he's overestimated consumption by a factor of 3, as you say, that means we actually would have 15 years of an all nuclear/electric world before the viable uranium got used up. Not better enough to be worth correcting him, IMO. "The world," as you put it, "doesn't care about" ten more years. The world is looking for the longest lasting possible energy source. Should we invest so much in something that's just going to be fossil fuels all over again?

Output, right. So anyway, after I put numbers to it, he over-estimated - using his logic - by a factor of 2, not 3. But so much of the rest of the logic is bad that I still wouldn't consider 7.2 TW as a good starting point for the discussion. However, since we are on it, here's a source for the calculation of longevity, using his logic:

According to the NEA, identified uranium resources total 5.5 million metric tons, and an additional 10.5 million metric tons remain undiscovered—a roughly 230-year supply at today's consumption rate in total.

http://www.scientificamerican.com/article/how-long-will-global-uranium-deposits-last/

Currently, we have about 440 reactors. If we needed 7200, that's 440/7200*230= 14 years under current usage patterns. So that's roughly where his math comes from.

But:

Further exploration and improvements in extraction technology are likely to at least double this estimate over time.

Using more enrichment work could reduce the uranium needs of LWRs by as much as 30 percent per metric ton of LEU. And separating plutonium and uranium from spent LEU and using them to make fresh fuel could reduce requirements by another 30 percent. Taking both steps would cut the uranium requirements of an LWR in half.

So combining those two yields an additional factor of 4: now we're at 56 years.

Second, fuel-recycling fast-breeder reactors, which generate more fuel than they consume, would use less than 1 percent of the uranium needed for current LWRs.

An additional factor of 100: now we're at 5,600 years and we haven't even brought seawater into the discussion yet.

**Notice that nowhere in the post did I reference the thermal input energy of the nuclear fuel. It's very much like discussing a car's fuel efficiency in terms of miles per gallon: the usage is given in units of volume (mass for uranium) per output, so we can skip the step of calculating (by efficiency or heat capacity per gallon/ton) the input heat.

 

[zoobyshoe]

Second, fuel-recycling fast-breeder reactors, which generate more fuel than they consume, would use less than 1 percent of the uranium needed for current LWRs.

An additional factor of 100: now we're at 5,600 years and we haven't even brought seawater into the discussion yet.

O.K. Nothing gets good until breeder reactors are brought in. Then the outlook is fantastic.

What's the problem? Why aren't all nuclear reactors breeder reactors? That's an unbelievable extension of the fuel. If we had even 500 years of that, much less 5000, I'd call that "nuclear utopia."

 

[russ_watters]

O.K. Nothing gets good until breeder reactors are brought in. Then the outlook is fantastic.

What's the problem? Why aren't all nuclear reactors breeder reactors?

My understanding is that it is all about money. Once-through reactors are cheaper to build/operate.

My concern is whether the spent one-through fuel can be reprocessed and then re-used in a breeder reactor. I don't want the next 50 years of current usage to deplete what we have so much that we end up running out because we used it wrong. Someone else will have to answer that though.

Edit: Gotta love PF: When Googling "why aren't breeder reactors used more", the first hit is a PF thread discussing it:
https://www.physicsforums.com/threads/why-arent-more-breeder-reactors-being-built.509686/

 

[zoobyshoe]

My understanding is that it is all about money. Once-through reactors are cheaper to build/operate.

My concern is whether the spent one-through fuel can be reprocessed and then re-used in a breeder reactor. I don't want the next 50 years of current usage to deplete what we have so much that we end up running out because we used it wrong. Someone else will have to answer that though.

I looked through the wiki article on breeder reactors and they explain fairly well why they're not in use. You can have a look.

I agree about the next 50 years. It seems to me they ought not to be building and using any non-breeder reactors. Because they get so much more energy out of the fuel they also vastly cut down on the long-term accumulation of waste, and that has impressed many green people (according to the wiki).

Here in California the wiki says 1/5 of the electricity is nuclear. That comes from just two nuclear plants. It seems to me that from 1/5 to 1/2 of the electricity being nuclear would be a manageable level.

However, I read the article on nuclear decommissioning, and that seems to be a farce. The old plants are just sitting there for decades. They aren't cleaning them out. Part of every plant's profit is supposed to be put aside to pay for the cost of dismantling them, so it should not be a matter of money. And there should be no such thing as "entombment." Old nuclear plants can't be allowed to accumulate if people want nuclear for the long haul.

Given that, with the right usage, nuclear could last thousands of years, that objection is tentatively taken care of. A big potential fly in the ointment is accidents. Fukushima, I've been reading, played havoc with Japan's economy, not to mention the worldwide uranium market. Japan reacted by taking all their nuclear offline. A bigger potential fly is countries like Iran, who say they want nuclear power but are almost certainly going to use it to also make bombs. They're simply not going to not make bombs. Every one who can has. They won't be any different. Since breeder reactors can produce weapons grade products, it seems to me no one should be building any breeder reactors.

Contradiction intended. The upside is wonderful, the downside is horrible.

 

[Ryan_m_b]

Cimmercial nuclear ships are not being built and will not be built for some time. They are not viable economically or practically.

Actually they may be economical, one of the reasons the NS Savannah was decomissioned is because of how cheap shipping fuel was back then, apparently even by the 70s fuel costs had risen enough that Savannah would have been cheaper:
https://en.wikipedia.org/wiki/NS_Savannah#Economics_of_nuclear_propulsion

 

[tom aaron]

Actually they may be economical, one of the reasons the NS Savannah was decomissioned is because of how cheap shipping fuel was back then, apparently even by the 70s fuel costs had risen enough that Savannah would have been cheaper:
https://en.wikipedia.org/wiki/NS_Savannah#Economics_of_nuclear_propulsion

Not at all. The capital costs, decommissioning, shipping restrictions make it completely uneconomical. A money pit compared to conventional energy use.

Where do you see it being used today? Why not?

 

[SMPS-PHYSICS]

What is the best way to produce electricity?
Nuclear : people are afraid of leaks and waste storage problems.
Coal: People are afraid of smoke pollution, and it may run out soon.
Oil same as above.
Wind inefficient and to costly.
Wave renewable but again too costly
Solar: it takes up to much land.

What do you think?

I'm tracking for some years the developments made by Dr Randell Mills, Chairman of Black Light Power [crackpot link deleted]

Dr Randell Mills specifically has developed a commercially competitive, nonpolluting source of energy that forms a predicted, previously undiscovered, more stable form of hydrogen called “Hydrino”.

 

[russ_watters]

However, I read the article on nuclear decommissioning, and that seems to be a farce. The old plants are just sitting there for decades. They aren't cleaning them out. Part of every plant's profit is supposed to be put aside to pay for the cost of dismantling them, so it should not be a matter of money.

I think that's part of the Yucca mountain politics: you can't decom a nuclear reactor if there is nowhere to put the waste.

A big potential fly in the ointment is accidents. Fukushima, I've been reading, played havoc with Japan's economy...

Not exactly.

It's a little known fact that in a crazy coincidence, one of the largest earthquakes and largest tsunamis in recorded history happened on the same day as the plant failure. What are the odds?

In seriousness, the earthquake/tsunami caused $16-$35 billion in direct damage. The total economic impact is estimated at $235 B.
https://en.wikipedia.org/wiki/2011_Tōhoku_earthquake_and_tsunami

The cost of the accident itself is expected to be about $105 billion, with half of that going to compensating affected residents and the other half for clean-up of the plant and surrounding areas.
http://rt.com/news/183052-japan-fukushima-costs-study/

Shutting down the rest of the nuclear plants in the country is expected to increase energy costs by $32B per year, so that's actually a bigger economic disaster than the earthquake itself. And that doesn't even include the $500 billion required to actually phase-out nuclear power over the next 20 years.

The costs of the accident itself are a small fraction of the costs associated with the earthquake and political decisions resulting from the accident. Summarizing:

-Total cost of the earthquake: $235 B (assuming that does not include the nuclear plant disaster)
-Total cost of the political decision to phase-out nuclear power: $600 Billion (includes estimated $100B for temporary shutdown associated costs)
-Total cost of the nuclear disaster itself: $105 B

So as you can see, of the $940 B total impact of the events that day, more than half ($600 B) is based on personal choice instead of need (I call that a self-imposed calamity) and only 11% is directly attributable to the nuclear plant accident, which is still less than half of the damage of the earthquake.

A bigger potential fly is countries like Iran, who say they want nuclear power but are almost certainly going to use it to also make bombs. They're simply not going to not make bombs. Every one who can has. They won't be any different. Since breeder reactors can produce weapons grade products, it seems to me no one should be building any breeder reactors.

What does the US or UK or even China building breeder reactors have to do with Iran getting nuclear weapons?

 

[zoobyshoe]

I was aware of all that, not that the links are not interesting. The fact is, nuclear accidents are an incendiary subject and Japan leaned way over backward to present the image of proceeding as cautiously and responsibly as possible. You call that a "self-imposed calamity," but I think it was in their best interest to do so, and it probably placated a lot of people. Regardless of the cause, any large nuclear accident like that is going to be a huge mess on every level.

Anyway, I read yesterday that they're thinking of bringing their nuclear back online. At least, there are rumors to that effect in the uranium market.

What does the US or UK or even China building breeder reactors have to do with Iran getting nuclear weapons?

I didn't put that well. I just meant to express the sentiment that, given the fact a country like Iran is probably up to no good in wanting nuclear power, I wish breeder reactors didn't exist (along with all things nuclear). I feel very ambivalent about them now, authentic love-hate.

 

[russ_watters]

I'm tracking for some years the developments made by Dr Randell Mills, Chairman of Black Light Power http://www.blacklightpower.com/

Dr Randell Mills specifically has developed a commercially competitive, nonpolluting source of energy that forms a predicted, previously undiscovered, more stable form of hydrogen called “Hydrino”.

Welcome to PF.

That's generally regarded to be a hoax/fraud.

 

[russ_watters]

I was aware of all that, not that the links are not interesting. The fact is, nuclear accidents are an incendiary subject and Japan leaned way over backward to present the image of proceeding as cautiously and responsibly as possible. You call that a "self-imposed calamity," but I think it was in their best interest to do so, and it probably placated a lot of people.

That's an awful lot of money to spend on advertising if all they really get out of it is "placating people". It's a complete waste of an enormous sum of money that their economy could really use. In either case, I don't want to quibble about the difference between "havoc" and "calamity", but surely you agree that it is self-imposed, right?

I didn't put that well. I just meant to express the sentiment that, given the fact a country like Iran is probably up to no good in wanting nuclear power, I wish breeder reactors didn't exist (along with all things nuclear). I feel very ambivalent about them now, authentic love-hate.

I still don't really understand. Are you saying you wish breeders didn't exist because you think Iran might build one to make bomb fuel? They're already making bomb fuel the conventional way (centrifuges), so there is no breeder reactor in their critical path/pipeline to getting nuclear weapons.

 

[zoobyshoe]

That's an awful lot of money to spend on advertising if all they really get out of it is "placating people". It's a complete waste of an enormous sum of money that their economy could really use. In either case, I don't want to quibble about the difference between "havoc" and "calamity", but surely you agree that it is self-imposed, right?

Yes, I agree it is self-imposed, but that's the way a nuclear accident played out in their culture. Ignore my editorial comment that it might have been in their best interest, which is a side issue. The bigger point was that nuclear accidents are a fly in the ointment.

I still don't really understand. Are you saying you wish breeders didn't exist because you think Iran might build one to make bomb fuel? They're already making bomb fuel the conventional way (centrifuges), so there is no breeder reactor in their critical path/pipeline to getting nuclear weapons.

Don't worry about it. My original impulse was to express my ambivalence as a kind of literary trope I've seen used a few times: to start out making an assertion, but end up directly contradicting it.

Consider the Japanese (since we're on that subject) saying, "Those who eat fugu are crazy. And those who don't eat fugu are crazy." Those who eat it are crazy because it can kill you. Those who don't eat it are crazy because it tastes too good not to eat. I was just reaching for an effect like that.

 

[gmax137]

... A bigger potential fly is countries like Iran, who say they want nuclear power but are almost certainly going to use it to also make bombs. They're simply not going to not make bombs. Every one who can has. They won't be any different...

Source please? As far as I know, not one of the countries with nuclear weapons has done it with uranium or plutonium that came out of a power generating reactor. Not one.

 

[zoobyshoe]

Source please? As far as I know, not one of the countries with nuclear weapons has done it with uranium or plutonium that came out of a power generating reactor. Not one.

Right, sloppy characterization on my part. The route taken is to claim they are refining the uranium for use in electricity generation by nuclear reactor.

 

[gmax137]

Right, sloppy characterization on my part. The route taken is to claim they are refining the uranium for use in electricity generation by nuclear reactor.

So your argument is, we here (in the US, or China, as examples) shouldn't build breeders, because the Iranians are enriching uranium in their centrifuges?

 

[zoobyshoe]

So your argument is, we here (in the US, or China, as examples) shouldn't build breeders, because the Iranians are enriching uranium in their centrifuges?

See my post #112.