Best energy alternatives to stop global warming

[The Jedi Master]

Or you could settle this like gentlemen

Pistols at dawn!

Agreed, anger is the path to the dark side.

In all seriousness, I realize my remark was a little cutting. I was no better than the other guy in this situation. Sorry.

[peadar1987]

That's not a real way of seeing things.

All fossils fuels had an increasing cost to day, just becouse they had a constant demand with a limit amount.

But if that demand decrease (more electric cars, less fossil plants, etc) but you still had the resources, then the cost decrease. Which make fossil plants more competitive than even were before.

Adding that is not cost efficient decommission a new or high quality fossil thermal plant. I would said that this approach can help a lot.

On the contrary, it's the only way of seeing it. Climate Change is a real problem. If we burn all of the fossil fuels, we release the CO2, climate change gets worse. The only way to stabilise CO2 levels is to leave the fuels in the ground, even if they are still economically viable without taking into account externalities.

I dont understand abbreviations, you mean thermal plants with combined cycle?

I know that you can not upgrade most of the thermal plants to combined cycle. But you can almost upgrade all thermal plants (or a least the ones with would last more) to capture co2, or add them some cogeneration process (you dont need an turbine for this, just a heat exchanger)

CCGT=Combined Cycle Gas Turbine

The problem with implementing cogeneration at the moment isn't in the power plants (as you've said, that's easy), it's with retrofitting buildings to accept hot water as a heating source, instead of electric heaters or gas boilers. I think all new developments should have cogeneration, there shouldn't even be a question about it.

That is not complete true, heat exchangers does not have always the maximun work rate. Becouse try to get to those efficiencies would be cost inefficient with old technology, but you can improve the existing heat exchanger with some kind of cover or sprayer to make them hydrophobic. This would increase the plant efficiency (not much, but all counts).

Well if you can get a more efficient heat exchanger, it is going to very slightly reduce the back-pressure on the turbine, which will give you a marginal increase in efficiency.

Apart from that, the performance of the heat exchanger can simply be described by an energy balance. The working fluid exits the expander, and it must reject a certain amount of heat so the fluid is subcooled before it enters the pump. If the heat exchanger isn't up to the job, you get cavitation in the pump, not a drop in efficiency. The way to deal with it is to reduce the mass flow rate of the working fluid, which has pretty much no effect on efficiency. You can analyse a Rankine Cycle system perfectly well without going into the specifics of the heat exchanger.

If you want distilled water, you use sea water in a open cycle (instead close), why you need an extra turbine?

If you want heat homes with your remaning high entropy heat, why you need an extra turbine?

Perhaps I misunderstood you. It looked like you were saying we should extract more energy from the working fluid before using the waste heat. There's an economic limit to the amount of heat you can get out of a stream of working fluid, because water has a huge change in density as it expands, one turbine can't handle the transition from 500 degrees to condenser inlet temperature, you need to have a series of them, each one bigger than the last. You fairly quickly reach a point where the cost of your extra turbine isn't compensated for by the increase in efficiency.

[ZetaX]

2-Thermal Fusion Nuclear Plants (20 or "who knows" years away)

More like 40 years actually. We might under good circumstances get a test reactor till 2034 that can run (almost) indefinitely and produces a net positive, but anything serious will probably post-ITER; you can expect ~20 years for ITER's life expectancy as a research reactor after it is completed, and only then it might be viable. Building those things takes years, up to two decades if you factor in lobbying, getting funds and getting permits. And yes, I know of the other types, but none of those can beat ITER for the same reasons: the life cycles are long and funding is sparse.

And why didn't I see those 35 other pages -.-

Edited June 22, 2014 by ZetaX

[phoenix_ca]

@AngelLestat: I gave you two videos because it was the quickest thing I could pull-up on short notice. Digging-up source material again for decisions made as far back as the 60s isn't easy; often there isn't even public record, so all we've really got to go on is their word and integrity...and the fact that the DoE hasn't funded research for any other types of fusion devices, and instead exclusively dedicated their time and money to tokamaks. They don't even make a nod to the existence of these other types of fusion on the ITER website, which is odd. You'd think they'd at least point-out that there are other ways being tried.

As for the salesman bit...am I supposed to take that as a compliment or a veiled insult?

More like 40 years actually. We might under good circumstances get a test reactor till 2034 that can run (almost) indefinitely and produces a net positive, but anything serious will probably post-ITER; you can expect ~20 years for ITER's life expectancy as a research reactor after it is completed, and only then it might be viable. Building those things takes years, up to two decades if you factor in lobbying, getting funds and getting permits. And yes, I know of the other types, but none of those can beat ITER for the same reasons: the life cycles are long and funding is sparse.

And why didn't I see those 35 other pages -.-

If by "life cycle" you mean the turnover between prototypes, you're wrong. For polywells and DPF designs it takes from a few months to a few years (far less than a decade) to make significant modifications to the design and build a new prototype. They have the benefit of being very small designs that can be put together very easily for research. Tokamaks, on the other hand, have to be absolutely gargantuan, requiring years of planning and construction just to build one. Granted, they need to add a lot of variability to the design like adjustable magnetic fields to get a more reasonable research life out of them, but it's not like they have the option of just going right back to the drawing-board and making significant changes. (I also find it rather amusing that tokamaks require superconductors to be efficient. The only superconductors we have now require serious refrigeration to near absolute zero. So you're building a reactor that is to be used as a heat source for thermal power, that requires super-cooled parts to contain the plasma in it. It's amusing, and a little bass-ackwards. So...what, are they waiting for room-temperature superconductors? Who knows how long that'll be. Polywells and DPF have the benefit of being based on currently available technology.)

Edited June 23, 2014 by phoenix_ca

[SargeRho]

The Superconducting Magnets aren't actually exposed to the heat that much. They are behind the reactor walls after all. Superconducting Magnets aren't really a new technology - MRIs and Particle Accelerators send their regards.

[AngelLestat]

I would love to put some turbine here. But the problem is that a wall is needed to control the flow to reduce the investment in turbines and get an average load, doing this we are also removing this show and screwing maybe the life cycle in the bay.

On the contrary, it's the only way of seeing it. Climate Change is a real problem. If we burn all of the fossil fuels, we release the CO2, climate change gets worse. The only way to stabilise CO2 levels is to leave the fuels in the ground, even if they are still economically viable without taking into account externalities.

But if your capture the 90% of the Co2 and you inject it back into the ground, then becomes a green source of energy. How much you would pollute if you make another wind farm or nuclear plant (also with the new power lines to transport the energy)?

If the oil or gas cost decrease, then this solution for sure would become usefull. Each fossil time that you convert is helping you to low the Co2 emissions. At the same time if you would make a new investment it can be in renowable energy.

This strike the problem from different angles.

The problem with implementing cogeneration at the moment isn't in the power plants (as you've said, that's easy), it's with retrofitting buildings to accept hot water as a heating source, instead of electric heaters or gas boilers. I think all new developments should have cogeneration, there shouldn't even be a question about it.

Yeah I know that. That´s why its important when a new neighborhood is planned, to include a sustainable approach in their design.

Is a lot more efficient had many houses sharing resources (hot water, electricity, etc) than individual houses trying to be sustainable for their own.

Well if you can get a more efficient heat exchanger, it is going to very slightly reduce the back-pressure on the turbine, which will give you a marginal increase in efficiency.

Apart from that, the performance of the heat exchanger can simply be described by an energy balance. The working fluid exits the expander, and it must reject a certain amount of heat so the fluid is subcooled before it enters the pump. If the heat exchanger isn't up to the job, you get cavitation in the pump, not a drop in efficiency. The way to deal with it is to reduce the mass flow rate of the working fluid, which has pretty much no effect on efficiency. You can analyse a Rankine Cycle system perfectly well without going into the specifics of the heat exchanger.

For that reason is a lot more usefull when its an open cycle as destilation or in some combined cycles I guess.

erhaps I misunderstood you. It looked like you were saying we should extract more energy from the working fluid before using the waste heat. There's an economic limit to the amount of heat you can get out of a stream of working fluid, because water has a huge change in density as it expands, one turbine can't handle the transition from 500 degrees to condenser inlet temperature, you need to have a series of them, each one bigger than the last. You fairly quickly reach a point where the cost of your extra turbine isn't compensated for by the increase in efficiency.

If you end with 70C, the extra investment to increase the energy generated it does not worth it, but it would worth if you use an extra heat exchanger to obtain hot water or use that heat to produce some other thing.

More like 40 years actually.

We always said 20 years, becouse is a lot of time, we never know what advances we can witness in that time. But yes, if we follow the programed steps already in curse, 30 or more years is a safe estimation. 40 to become a competitive source.

As for the salesman bit...am I supposed to take that as a compliment or a veiled insult?

None. I just wanna to see if it was Canadian proud or something else

If by "life cycle" you mean the turnover between prototypes, you're wrong. For polywells and DPF designs it takes from a few months to a few years (far less than a decade) to make significant modifications to the design and build a new prototype. They have the benefit of being very small designs that can be put together very easily for research. Tokamaks, on the other hand, have to be absolutely gargantuan, requiring years of planning and construction just to build one. Granted, they need to add a lot of variability to the design like adjustable magnetic fields to get a more reasonable research life out of them, but it's not like they have the option of just going right back to the drawing-board and making significant changes. (I also find it rather amusing that tokamaks require superconductors to be efficient. The only superconductors we have now require serious refrigeration to near absolute zero. So you're building a reactor that is to be used as a heat source for thermal power, that requires super-cooled parts to contain the plasma in it. It's amusing, and a little bass-ackwards. So...what, are they waiting for room-temperature superconductors? Who knows how long that'll be. Polywells and DPF have the benefit of being based on currently available technology.)

I always read science news since I was little, I am aware of all fusion progress over the years.

I know that it would be much easy get a fussion propulsion system in space than a power generator.

But I dont really understand the physsics involved enoght to compare what approach is better for electricity generation.

So I dont have an opinion in this matter. I just based trust in the judgment than country advicers may had to know what it would be the best use for the money.

Edited June 23, 2014 by AngelLestat

[ZetaX]

(I also find it rather amusing that tokamaks require superconductors to be efficient. The only superconductors we have now require serious refrigeration to near absolute zero. So you're building a reactor that is to be used as a heat source for thermal power, that requires super-cooled parts to contain the plasma in it. It's amusing, and a little bass-ackwards. So...what, are they waiting for room-temperature superconductors? Who knows how long that'll be. Polywells and DPF have the benefit of being based on currently available technology.)

With a plasma of 100M K, your argument is pretty invalid. Keeping something at 3K or at 300K does not make much of a difference then; the former only requires you to plan bit more for thermal expansion effects. They by the way also rely on cooling by superfluid (and therefore very heat-conducting) helium, with the coolant flowing through pretty small capilars between the bundles of superconducting wire.

[phoenix_ca]

Ah, well at least that explains how it's cooled, but there's still the issue of all that power being eaten for refrigeration. Reaching net positive energy is more difficult. It's not like refrigeration to around 1°K is easy. O.o A design that doesn't need a superconductor has a distinct advantage right from the start because of that.

All that aside, the fuel choice is likely the biggest issue. D+T fusion produces a high-energy neutron (14.1MeV), which will certainly turn the reactor itself radioactive. Not really a solution to the problem of nuclear waste. That and the problem of tritium breeding hasn't been solved. It may well be eventually, but p+B11 reactors have the advantage there again by using fuel that is (ridiculously) abundant in nature.

Edited June 23, 2014 by phoenix_ca

[Elthy]

You wont need to go to 1K, there are superconductors up to 138K, where liquid nitrogen is enough...

[SargeRho]

Ah, well at least that explains how it's cooled, but there's still the issue of all that power being eaten for refrigeration. Reaching net positive energy is more difficult. It's not like refrigeration to around 1°K is easy. O.o A design that doesn't need a superconductor has a distinct advantage right from the start because of that.

All that aside, the fuel choice is likely the biggest issue. D+T fusion produces a high-energy neutron (14.1MeV), which will certainly turn the reactor itself radioactive. Not really a solution to the problem of nuclear waste. That and the problem of tritium breeding hasn't been solved. It may well be eventually, but p+B11 reactors have the advantage there again by using fuel that is (ridiculously) abundant in nature.

I think D-T Reactors use a Lithium "blanket" around the reactor to capture the Neutrons, which heats up the blanket while also producing Tritium. In fact, those Lithium blankets could produce all of the Tritium needed by the reactor. It's one think ITER is going to test.

Additionally, Spherical Tokamaks may prove to be better than regular Tokamaks, and may not actually require SC Magnets.

[phoenix_ca]

You wont need to go to 1K, there are superconductors up to 138K, where liquid nitrogen is enough...

The comment about superfluid helium is what prompted me to say 1°K. Isn't helium only a superfluid around 1-2°K?

I think D-T Reactors use a Lithium "blanket" around the reactor to capture the Neutrons, which heats up the blanket while also producing Tritium. In fact, those Lithium blankets could produce all of the Tritium needed by the reactor. It's one think ITER is going to test.

Additionally, Spherical Tokamaks may prove to be better than regular Tokamaks, and may not actually require SC Magnets.

They're still trying to figure-out how to adequately breed tritium in those reactors. It may never work. It probably will, but that isn't my main issue.

My main bone to pick with tokamaks is the D+T fuel requirement. They can't use p+B11, so they're going to irradiate themselves, period. After running it for a while, you'll have a reactor that is radioactive all by itself. People are already edgy about low-level nuclear waste from fission power plants. Purely from a marketing perspective, I'd much rather be able to say that fusion is far cleaner in that regard.

[SargeRho]

It's the high level waste everyone is *****y about, not the low level waste.

D-D and D-T fusion also generates a lot more energy than p-B11 fusion, it'll come down to wether the higher energy output of D-T fusion is worth having to replace parts of the reactor every once in a while.

[ZetaX]

Ah, well at least that explains how it's cooled, but there's still the issue of all that power being eaten for refrigeration. Reaching net positive energy is more difficult. It's not like refrigeration to around 1°K is easy. O.o A design that doesn't need a superconductor has a distinct advantage right from the start because of that.

You need to keep a couple of litres of helium cool for a reactor with an output of more than 1GW. The energy cost should be pretty irrelevant.

You wont need to go to 1K, there are superconductors up to 138K, where liquid nitrogen is enough...

No. Only classical superconductors work for the field strength you need. Type 2 superconductors's superconductivity would just break down. And as I mentioned you use superfluidity of the coolant for several reasons, too.

[phoenix_ca]

It's the high level waste everyone is *****y about, not the low level waste.

Uhhhhh...I think the posts in this thread go toward showing that there indeed are people who get edgy about low-level waste. Hell, I've even met people like that. The ones most crazy about it are pretty much certifiable though...

D-D and D-T fusion also generates a lot more energy than p-B11 fusion, it'll come down to wether the higher energy output of D-T fusion is worth having to replace parts of the reactor every once in a while.

True enough. More energy, easier to create fusion with, more radiation. Although, much of that energy is in the neutron radiation, and can only be collected as thermal energy. DPF may provide a way to use direct conversion, which is much more efficient. We'll have to wait to see how it all shakes-out.

[Seret]

It's the high level waste everyone is *****y about, not the low level waste.

Reactor parts with induced radioactivity would be medium level waste. Low level is things like overalls. A fusion plant would generate both, but it isn't a big problem, as we have a disposal stream for both. As you say, it's only the high level wastes that are problematic.

[78stonewobble]

Reactor parts with induced radioactivity would be medium level waste. Low level is things like overalls. A fusion plant would generate both, but it isn't a big problem, as we have a disposal stream for both. As you say, it's only the high level wastes that are problematic.

It's only a problem, if you handle it extremely poorly.

It's not like you can pour other toxic things into the groundwater supply or spread over large areas in the air without problems either.

And we do use plenty of problematic materials all over the earth, even if they can be huge problems if handled poorly.

[Seret]

It's only a problem, if you handle it extremely poorly.

We are handling it poorly. There's nowhere to actually put high level wastes, the vast majority are still sitting in their cooling ponds waiting for a solution.

[SargeRho]

True enough. More energy, easier to create fusion with, more radiation. Although, much of that energy is in the neutron radiation, and can only be collected as thermal energy. DPF may provide a way to use direct conversion, which is much more efficient. We'll have to wait to see how it all shakes-out.

Maybe we can find a sufficiently plentyful Helium 3 source that doesn't involve processing 150 million tons of moon dust for a kilogram of Helium 3, or mining the Gas Giants. D-Helium 3 fusion produces even more energy, and is aneutronic. It produces 14.7 MeV protons, which can be used directly for power production.

[78stonewobble]

We are handling it poorly. There's nowhere to actually put high level wastes, the vast majority are still sitting in their cooling ponds waiting for a solution.

I'd rather call that "not handling" it.

Any odd desert or deep sea trench would do...

The waste is irrelevant in the bigger picture. We would have to granulate it into tiny airborne easily absorbable dust particles and spread it with planes over the worlds major cities for it to be a BIG problem on a world wide scale. As far as I know... noone has suggested that kind of solution.

Until then, it's a very minor local enviromental problem. Regional, if we set fire to it, though I wonder why anyone would do that.

[rtxoff]

I wonder why someone would fly an plane into a skyscraper, nevertheless it happened.

I wonder why someone would detonate himself, nevertheless it happened.

As soon as this waste is there it won't go away by itself for many years. And for many years it will be our burden and the burden of many generations to come.

To think "putting it somewhere in a desert is like putting it out of your mind" is pretty foolish.

The best would be avoiding to produce any waste at all, however if that is not possible because we depend on the energy nobody of us has the right to downplay this matter.

The waste question is a very serious one. Anyone wanting to have a serious discussion here better not forget that.

[SargeRho]

Vitrify it, put it deep into the Earth into geologically stable formations.

[peadar1987]

Vitrify it, put it deep into the Earth into geologically stable formations.

And if any terrorist wanted to cause problems, they'd have to answer some very awkward questions about why they were running a large-scale, highly obvious mining operation right above a nuclear waste storage facility.

[Elthy]

Afaik the waste produced by fusion powerplants decays much faster than fission products, so you have to store it for "only" about 100 years so it can be stored in castors like todays waste is, except that you can open it after a reasonable time...

[Seret]

Vitrify it, put it deep into the Earth into geologically stable formations.

That's the theory, the practice has proved somewhat more difficult.

Eventually everybody will just have to bite the bullet and push through proper long-term storage facilities. I suspect most countries will have to build their own, I can't see many folks being keen to accept everybody else's waste.

Even though fusion plants won't generate the high-level wastes we're stuck with those generated by existing fission plants.

[AngelLestat]

Well if we are talking about fusion, why not talk about collect the Sun energy in space? Something that I see promissing if Skylon becomes a reality in the next 10 years.