88 replies to this topic

[forcestormx]

Traditional hot fusion (D-T initially, then eventually D-3He, which doesn't require a thermal cycle) long term.

Thorium-232 and Uranium-238 breeding cycles for fission in the short term, preferably in fast reactors with high proliferation resistance.

[RedHairDave]

lftr? thorium based reactors are sweet, but why bother, solar in space is free forever. no fuel, no running out, no emitions or even the possibility of some disaster.

[StompyMcGee]

I live in Scotland, so I chose 'other'. Specifically, wave and tidal, since we have a blooming massive coastline.
Not in favour of winf; I live within 6 miles of Europe's largest on-shore wind farm, and the damn things are still more often than they turn. Especially in winter.

[Catamount]

RedHairDave, on 21 March 2012 - 11:22 AM, said:

lftr? thorium based reactors are sweet, but why bother, solar in space is free forever. no fuel, no running out, no emitions or even the possibility of some disaster.

Solar is nice to the extent that it's profitable and feasible, but when it comes to powering a civilization, it doesn't even work on paper, let alone in practice.

The sun provides the Earth with ~1367W/M^2, and iirc, that's at TOA, not the surface, which only receives about half of that. As of 2008, we were consuming about 15TW. So even if we were talking in space, and that's not a bad idea (again, on paper), since you'd get about twice as much sun, you'd need eleven thousand square kilometers! Put another way, it's basically suggestion lifting something the size of the entire state of Massachussetts into space. On the Earth's surface, you'd need double that amount of solar panels.

Again, that's not for future power consumption, which will probably dwarf present figures between population growth (which is thankfully start to taper), and further industrialization of the world. By 2050, we might well be consuming 50TW, instead of 15TW. It might not be any more sane than consuming that amount of energy from fossil fuels, which are something like one ten millionth of a percent efficient in how we liberate energy from them, but it's not really much more sane

That's why much denser forms of power generation, like Thorium, and fusion (probably Polywell, around 2020 or so), are so valuable. They're not just fairly clean and perfectly safe (Thorium reactors CANNOT melt down), they're also dense enough to actually practically meet all the world's power needs.

Solar's still great, considering present forms of power, but I can't think of many things I'd like better than a form of nuclear energy that presents basically no risks (as if nuclear presents risks anyways? Coal killed more people in 4 days than nuclear has in the past 61 years), and runs off of something not so completely exotic and "dirty" as U235 (not compared to fossil fuels, but still...).

Edited by Catamount, 21 March 2012 - 01:40 PM.

[diana]

Using the planet's magnetic field, since its basically a giant magnet, like those that generate power, and Tesla.

[Zakatak]

British Petroleum is expected to have completed their Dyson Sphere by about 2017 or so, by the way, so everything else may be unnecessary.

[Vexgrave Lars]

Wind.. done with this ... 1 Moving part, a prop on the front and coils/capacitor. Of course you'd add horizontal magnets and a secondary magnetic bearing for stability to remove the single mechanical bearing he's using.. Neodium is CHEAP and easy to make, recycled bottles and copper for the rest. With the right housing, it would turn on the mere variation of temperature between the ground that the air, because there's no mechanical drag. Mount 5 or 6 on each roof like a weather-vane. Cheap, easy to replace and works 24 hours a day. Ohh.. forgot to add.. SIlent.. No parts would ever touch, the reduction in wear on current giant "federal" green turbines by comparison, is as clear as night and day.

Course.. if GE got wind (LOLZ) of it.. they'll sue you to death, and then have their lawyers use witchcraft to summon you back for a lil more court mandated suing. The problem with humanity is.. we all know the problems, we have many many acceptable solutions, it is to our disparaging ends that our vanity wont let us put aside our greed, my two favorite foundation sins, which all others rely upon.

Edited by Vexgrave Lars, 21 March 2012 - 02:18 PM.

[RedHairDave]

@ catamount

Quote

[color=#959595] you'd need [/color]eleven thousand square kilometers![color=#959595] Put another way, it's basically suggestion lifting something the size of the entire state of Massachussetts into space[/color]

remember step one is building a space elevator, so thats not an issue, we could put any number of solar panels up in space and they would never wear out. (aside from impacts, but if we have a space elevator, we can clean our orbit really easily)

although if i have to settle for something else, LFTR is my number 2 choice.

remember we can build a space elevator right now, we have the technology. it would cost about what the usa spends on its military in 4 years. then the solar panels would cost a fraction of that to cover all of earth energy needs, including making a super conductor power grid. the only thing stopping that is power, with the ability to put as many panels in space as we want, power is no longer an issue. it would take time and **** tons of money, but then would there be war? limitless power so cheap it would be hard to charge for it. sure there would still be religious conflicts and other theological or moral conflict. but no more greed based conflict.

with the huge win of being able to build space ships. not shuttles or space capcules,. full on real space ships. no weight limits, no size limits. and power it with LFTR

Edited by RedHairDave, 22 March 2012 - 05:36 AM.

[Catamount]

Even with a space elevator, lifting billions or trillions of pounds of solar panel into space is about the least economical way to do things. It would probably cost vastly less money to shift the entire planet over to fusion power. In fact, it'd be cheaper just building the solar panels on Earth, and accepting the size difference.

But either way, we're talking about not just building the largest structure even made, but probably building something equal in size to every building constructed by humanity in the past several decades.


We should still do solar where applicable, again, I'm absolutely a fan of it where feasible, as goes for tidal, geothermal, and wind. But while that might take some of the load off for now, long term we need something with a much greater power generation per unit of volume.

My bet's still on Polywell fusion. The Navy's still funding them, and despite the military-imposed information embargo, what information was required to go along with the additional ARRA funding, and the company's own roadmaps basically say they should be up and running with a full reactor by 2018 (tokamak designs like ITER could do it too, I suppose, but the size requirements are enormous, so I'm not sure what the point is).

Polywell reactors are really what you're after for spaceships, as well. They're very small, ideal for space applications.


As for the consequences of massive quantities of cheap power, well that remains to be seen. If we're wise enough to make good use of it, it'll mean humanity won't have to deal with much of the present reality of ecological damage, climate change, energy competition with the developing world, and a long-running set of problems will finally be over for us, allowing us to focus on advancing as a civilization instead of constantly trying to catch up to the consequences of where we already are, and perhaps finally giving future generations new, more interesting problems to solve (isn't that what it's all about?). If we're exceptionally stupid, then instead it'll cause a huge economic rebound effect, which I could see, in the worst of situations, causing demographic transition effects the likes of which we've never seen, and dooming us all to some miserable, Soylent Green style mess.

Either way, we need this, so if we're not smart enough to make use of it wisely, then I guess we were doomed to fail as a civilization a long time ago. I frankly think the new generation of people coming into power in the world is a lot wiser than the one that got us into this mess in the first place, as they rightly should be (such has been the trend for a long time), so I see plenty of reason for optimism.

Edited by Catamount, 22 March 2012 - 05:57 AM.

[RedHairDave]

the space elevator doesnt need to be the largest structure imaginable, its a mind blowingly long ribbon of carbon nano tubes attached to a platform(at sea to start) then using the ribon and the base structure you start putting mass in orbit to make the "yo-yo" and send up some kind of reactor and laser, also a laser at the bottom. then you can start sending up several thousand tons at a time, each trip lasting 3 days.

the elevator is powered by the reactors at the bottom and top using a laser to transfer power to the unit. then after the solar panels are up you can ditch the reactor, and start enjoying the limitless power. the side effect of the elevator is space exploration and the advancement of science. what if it only cost a penny per pound to go to space, instead of $10000 per pound.

[Catamount]

Not the space elevator!

The MASSACHUSETTS SIZED SOLAR PANEL (which would probably be a PA sized solar panel within a few decades to keep up with increasing demand... better hope it never falls down )


The time and money that would go into making that could just as easily be spent on far more practical proposals. Now, the space elevator is a must. Cheap access to LEO is of paramount importance for all sorts of reasons; lifting something half a dozen orders of magnitude larger than any structure every built into space (even piece by piece) just isn't necessarily one of them


Also, I don't think it'd be nearly free. First off, a structure that big could never avoid all the space junk out there, so you'd have to basically "clean up" LEO, a hugely expensive endeavor that would take years, if not decades, of massively expensive work of "chasing down" stuff, and even then, at that size, the chance of micrometeor impacts or even larger objects impacting is many orders of magnitude higher than, say, for a satellite or space station, so maintenance would be a nightmare.

Even after that, we're talking about getting dozens of terrawatts of power down from a centralized source. How on Earth are we going to do that efficiently?



Now, maybe we could solve all these problems, but again, it all seems a lot less practical than just developing better nuclear tech.

Edited by Catamount, 22 March 2012 - 06:20 AM.

[RedHairDave]

it is less practical, no doubt, but it has such a larger pay off. sure the reactors will solve todays problems in time for tomorrows. but the elevator and solar panels solves todays problems and likely at least some of tomorrows. clean LEO is not that hard. we are tracking all particulate matter right now, so its just a matter of putting something in the way to capture the projectiles and then pushing it into earth where it will burn up. there is a jell like substance that nasa made just for that purpose. its very light and can be very large. if put in orbit in large armounts available to be lifted by a elevator, it wouldnt take more than a year. projections from the people in texas that track everything in orbit.

so avoiding space junk, not that hard, from the mouths of those who track the stuff. also no space junk would be able to significantly damage the tether or the elevator. or the weight at the end. also from those who are designing the elevator. they arent concerned with junk.

the best part of the carbon nano tube tether is that it can be a super conductor, so thats how you get the power down, or you can equip each solar array with a lazer and just shoot it down(inefficient if cloudy) no limit to how many you can put up. they can be folded flat as nasa has done with solar pannels for years, and stacked as high as a building, then sent up. 6 day round trip. 6 months in and the state sized solar farm is up there. all the while bringing back the space junk collected as someone somewhere is not happy with it burning up in the atmosphere so they just bring it down.(empty elevator anyway why not. on the way back anyway)

Edited by RedHairDave, 22 March 2012 - 06:37 AM.

[Catamount]

You can't lump the space elevator and solar panels as if they're a package deal. The former may be required for the latter, but the reverse is not true. Building a space elevator should and will be done regardless of what happens with our energy infrastructure.

I also don't see how you could transfer down energy on that scale by laser. How would you convert that to electricity? Using an absurdly sturdy photoelectric cell made of presently non-existant materials? I sense a joke coming there, something along the lines of Yo dawg, I heard you like solar panels, so I gave you solar panels, to capture the energy collected by your solar panels, so you can collect sun while you collect sun

Even by tether, do you have any idea how much energy dozens of terrwatts is? Maybe if you split it into a million solar panels with a million space elevators it could be done, but that's redundant for space travel, and grossly increases the difficulty of the undertaking.

That also still leaves the problem of maintenance, especially from natural impacts. What are we going to do, but a million laser based CIWS systems onboard? (there goes another few trillion dollars...) Even that probably wouldn't be enough. You have to realize the kind of surface area we're talking about here.


Plus, we're still talking about building a solar panel THE SIZE OF A MIDDLING US STATE. Go outside right now and look out as far as you can see in every direction. Unless you live very high, everything you see is millions of times smaller than he solar panel(s) we'd need. If you live in a forest (and can't see far), it's going to be billions of times bigger. The word impractical doesn't begin to cover it.


So let's say we had practical fusion instead (and honestly, it would require no more in new technologies to make feasibly work). We could either build a fusion-based infrastructure, maybe with thorium reactors as well if there's a place for them, and end up with a system that was vastly easier and cheaper to build, still gives basically limitless energy very cheaply, and is a vastly, vastly, vastly more flexible power infrastructure (we wouldn't have to keep building new solar panels in space to keep up with increasing demand)... or, we could undertake the biggest engineering project in human history, by a factor of a million, easily spending more money than the entire EU generates in a year, and then lifting that entire thing into space, probably spending the EU's yearly GDP a second time over (even at $1 a pound, and even that'd be a hard number to meet), just to give us the same thing.

I just don't see the advantage of the solar approach here.


Also, while we can have a space elevator without solar panels, so they don't help us in space, Polywell fusion does help us in space. Extremely compact 100MW reactors would be about the best thing that could happen for us. Right now, we have a very promising way to get around space, ion and EM based engines. They're good because they have a very high specific impulse (meaning they give a lot of thrust for the amount of fuel they burn), but the amount of thrust they give in total depends on power available, so with present power source, they're very efficient, but not very powerful overall. With a 100MW reactor onboard, a ship could use an engine like that and not only be efficient, but have very high overall thrust.

That kind of technology would do for interplanetary travel (say, to go to the asteroid belt for resources) what a space elevator would do for travel to LEO. Just imagine what a leap that would be for our civilization: easy access to the whole of our own solar system.

Edited by Catamount, 22 March 2012 - 07:08 AM.

[RedHairDave]

the power transfer could be done down the tether. i dont understand it totally,but carbon nano tubes are capable of being super conductors and a ribbon that size could handle several times earth's power requirements as of right now, thats only one. no reason we cant have 10-20 around the equator, after the first, every other is massively cheaper.

the solar panels with lasers shooting at other solar panels might sound funny, but you can collect power in the dark of night. so that means that you can have the solar panels connected to a "in space infrastructure" where super conductors are easy to make, and beam down power in concentration far greater than the sun normally does day or night. changing targets as the clouds move. but that would only be necessary for places that cant be connected by hard connection for whatever reason. super conductors are possible now, just take power to create(cooling) with the limitless power of the sun, no reason we cant.
Neil deGrasse Tyson also thinks we can right now.
the reactors are more practical for today, no question. but why think so short sighted. its how the political situation in the usa is forced to think, but not in theory land that we are. it would take longer than 8 years for the system to really pay off, so i understand why no presidant would ever commit 40% of the us budget to that, with no pay off in his term. but it would pay off, and huge

damage is also a limited issue, carbon nano tubes are very very strong. they also self repair(or can in theory)
the space elevator is the first step in serious space exploration. it allows the construction of real space ships, not just little things we have done up till now

Edited by RedHairDave, 22 March 2012 - 07:30 AM.

[Catamount]

Again, I'm absolutely not seeing the advantage of this massive solar array over next gen nuclear tech.

The maintenance would be huge (unless our magical multi-trillion dollar science fiction CIWS system was protecting it from meteors), building it would be vastly more expensive and more difficult, getting something that big up there would be enormously difficult (even a few tons at a time, it would take millions of trips), it's inflexible for power unless you intend to do a never-ending expansion of the solar array, and getting that sheer quantity of power down and distributed would be very tough (you can't do it by laser; no material exists that would survive the beam, let alone covert it to electricity, and it would probably take thousands of very thick ribbons to do it the old-fashioned way).


On the subject of superconductors, carbon can conduct electricity in that form very well (graphene does it absurdly well), but to be superconducting, a material has be very, very cold, and in space, contrary to popular misconceptions, the problem isn't that things are cold, but often rather than it's hard to keep them from getting hot. Space isn't "cold"; it doesn't conduct heat, period, because it's nothing. So any object in the sun is actually going to get very hot, and there's no efficient way to keep it cool. So superconducting in space outside of permanent shade is out of the question. Even if you stuck it behind the solar panel, it'd be heated by reflected energy from the Earth (which gives off every bit of what the sun puts into it, so, a lot of heat in the form of longwave radition).



Space elevators are a must; again, that's a no brainer. But building a solar panel the size of a US state, or a small nation, and then lifting it into orbit, is just not going to happen. It'd be the most expensive way you could possibly generate power.

Besides, like I said, we need fusion reactors anyways for space travel.

Edited by Catamount, 22 March 2012 - 08:03 AM.

[RedHairDave]

you may be right, i am not involved with any project involving this at all. just very intrested in it and have been looking into those who are. the tether could handle a lot of power, all that earth uses today could easly be transfered down the tether from my understanding, not a huge one either. the one they plan to use to build it. it will be there to use, why not use it. if nothing else it could provide all of the usa and canada and mexico with limitless power.

the damage isnt a concern of those working on it, not sure why, but they have said before that they arent concerned about impacts. something involving new flexible solar cells.for some reason knocking holes in it isnt much of a problem. maintence is expected to be minimal, there are solar panels up there that are woking and have been for 10 years. those are the old kind also, where holes are an issue.

making it a super conductor it needs to be much less cold than all old style materials. and from the people lookin into it, very doable, maybe they have a plan involving shade, i dont know. you could be right, and i love talking about it btw, but i still like the idea of letting the pros do their job, by that i mean, if you want fusion, go to the master, the sun is doing its thing with or without us, lets use whats there instead of building our own. there could be unknown issues with the new reactors, (although unlikely, its possible) nothing a solar farm can do will ever hurt anything, if it crashed into the earth somehow, it would burn up and not be a problem,

also it wouldnt be one huge solar pannel, but many many smaller ones linked. in a farm.

but i am all for the new reactors available, LFTR is my favorite and can be scaled down to the size of a 18 wheeler while providing power to a whole city.

Edited by RedHairDave, 22 March 2012 - 08:17 AM.

[guardiandashi]

there are potentual solutions for most of the problems.

one thing that I have noted is that from what I remember most energy use occurs in several "windows" of time. there is a spike in usage between ~5-6 am and ~9am local time and another spike at ~5:00 to ~7:00 pm local typically with a higher average usage during the day than at night most places.

this is actually not horribly bad for solar as one potentual solution to the "morning" spike would be "battery assist" units IE batteries that were hooked to the solar "grid" and charged by the arrays whenever demand was less than supply.

additionally if every reasonable home/building was upgraded with a "grid tie" or similar solar array you could reasonably expect to reduce the load on the "grid" significantly.

now bear in mind I am not saying it would eliminate the need for other power generation sources, what it can do however is reduce the need.

for example my house over the last year used 1800 kwh according to my power utility. devide that by 12 months and it is ~150 kwh/month and at an average of 30 days/month that means I use ~5kwh/day or ~0.3125 kw/hour of daylight the point here is that a lot of small individual solar arrays do add up to an (effectively) huge array.

part of the reason they weren't as concerned about damage in modern array materials is that many modern arrays are somewhat "self healing" or able to absorb damage in small portions of the "panel" with only limited loss of function mostly in the realm of "efficiency"

Edited by guardiandashi, 22 March 2012 - 11:04 AM.

[Catamount]

There are certain areas where solar makes a lot of sense, places like the southwestern US where it's always sunny. Taking advantage where possible will take some very immediate stress off us for power generation, and that's hard to argue with.

Edited by Catamount, 22 March 2012 - 12:00 PM.

[RedHairDave]

although, its impossible to argue with the utility of modern reactors, they rely on nothing that we dont control and thats a huge advantage, not to mention the way it can be placed a few feet from the target, instead of out in space like my plan. i still think my plan can work. but to be honest, the reactors such as LFTR and the ones you mentioned are much more functional and will be ready much sooner with a much smaller investment and less unknowns.

another issue would be the recent solar storms, which would likely disrupt space based solar power, at the least you would think they would have to hide them behind earth in such a scenario and that would disrupt power.

also battery back up is infeasibility with current tech, at least till they prefect the ultra capasitor.(made of carbon nano tubes and is capable of holding a whole citys worth of power and discharging it instantly or over time.

[Seabear]

This is not "either/or" but rather more of "all of the above". There is not one energy souce that will answer all the worlds needs nor work in the many varied locations in the world. Besides, do we really want to give another group the strangle hold over energy production that the oil companies now have? Options and choice will make things cheaper and more user friendly.