[QUOTE=japelprime;134835]
Using windmills:

Using solar cells:
If there are solar cells then you have battery nearby.

Using waterfalls:
Mainly needs big land area and waterfall of course.

Using geothermal power:
and instead of oil you have steam (or you hope to find steam). Downside of this is H2S Hydrogen Sulphide that gives corrosive atmosphere.

Using Nuclear energy:
That can be used everywhere safe....by the book.[/QUOTE]
[COLOR="Sienna"]Windmills[/COLOR] are great in certain areas, they like the rest are [B]part of[/B] [I]the solution[/I]. Many places have enough wind that they need little stand by power to make up for the lack. And in many costal areas, there is on-shore off-shore wind virtually every day. Also, wind has started to be looked at more seriously again for use in shipping to reduce the power need from the engines, or to speed the journey. Rather than masts and sails, the use of a kite (in manner similar to a spinaker sail), the attachment and deployment system can be added to an existing cargo/tanker ship.

There is no real need for [COLOR="#a0522d"]solar cells[/COLOR] to have batteries nearby. If the cells are hooked to 'the grid', cells act as a peaker plant. They provide power during daylight hours when power demand peaks. Air-conditioners are most used during the height of summer when the sun is at it's brightest. Manufacturing peaks during daylight, as does office use of power. Also, solar power is not solely photovoltaic cells, there are several megawatt scale plants that are solar-thermal. Solar-thermal plants can store the heat off-line and use it during night or to peak. Also, solar hot water systems for houses, etc. do not need a battery.

By [COLOR="#a0522d"]waterfalls[/COLOR], I take it you mean hydro power. There is no need to have a water fall near by, nor a significant dam. The is a good solution for a mountain cabin. Divert part of the flow of a local stream into a small side stream, build a fairly flat path for the water to flow, then use a downspout to provide fall. In Norway, it is no uncommon to have a hydroplant located in a fjord. They take water from a small lake and lay a pipe near the stream. Norway generates a [B]large[/B] portion of their power by hydro.

[COLOR="#a0522d"]Geothermal[/COLOR] is not as bad as you portray. A growing use of geothermal 'power' is in the HVAC realm. Most areas have more moderate temperatures subsurface, than in the atmosphere. Coiled loops of copper or PEX are placed 2-5 meters down in a trench. Water, or other fluid is slowly pumped through the coils. The cooler(in summer)/warmer(in winter) fluid is run through a heat exchanger in the HVAC system. Since the majority of the 'power' used during peak times is the actual heating (as with a burner) or cooling (with a compressor), the pretreatment from the geothermal system will make a dramatic impact. Again this is [B]part of[/B] the solution. Also, the H[SIZE="1"]2[/SIZE]S problem is not as bad as one might think in the tradition geothermal system.

You left out 2 growing power sources, one large, the other minor.
'[COLOR="#a0522d"]Biomass[/COLOR]' is a diverse bag of sources, but they all share the bio commonality.
There are gas based systems: landfills, sewage sludge gas, agrocultural waste gasses, and a few others. These systems generally burn the gas in an engine, converting the CH[SIZE="1"]4[/SIZE] to CO[SIZE="1"]2[/SIZE], which lowers it greenhouse power. These systems are also used (sometimes) for the heat produced (either using it to boil water for more power or in the process that produces the gas). Then there is also the solid based bio mass systems, like burning waste sawdust, sugar canes, dried sludge, trash, etc. They use the heat for power. There are few forms of liquid bio mass systems, like waste cooking oil systems (the good bio-disiel).
The second growing source, is [COLOR="#a0522d"]tidal/wave[/COLOR] power. This is usefull along coastlines, like to power a lighthouse or a village. There are at least 5 types of systems that are used/being built to harvest this power.

Nuke is only [COLOR="#a0522d"]part of[/COLOR] the solution. The [B]true solution[/B] is to look at all of the availble tech and use them all as appropriate. This includes sustainable building plans that make them require less power.

[QUOTE=Uncwilly;134841]Nuke is only [COLOR="#a0522d"]part of[/COLOR] the solution. The [B]true solution[/B] is to look at all of the availble tech and use them all as appropriate. This includes sustainable building plans that make them require less power.[/QUOTE]Hallelujah!

Someone who groks the situation.


Paul

[quote=Jwb52z;134804]that said these Toshiba reactors use a basically harmless substance for the process and there's nothing that can really happen because the power produced is so low that none of the general problems can happen.[/quote]Whoever said they used a basically harmless substance did not know what they were talking about! If something can produce enough energy to be useful in a power-generation device, then at least some problems are possible.

[quote]Edit: Here's the info that I think will satisfy your "type of fuel query" that I found:
"Unlike traditional nuclear reactors the new micro reactor uses no control rods to initiate the reaction. The new revolutionary technology uses reservoirs of liquid lithium-6, an isotope that is effective at absorbing neutrons. The Lithium-6 reservoirs are connected to a vertical tube that fits into the reactor core. The whole whole process is self sustaining and can last for up to 40 years, producing electricity for only 5 cents per kilowatt hour, about half the cost of grid energy."[/quote]I already read that exact paragraph before making my preceding posting. As I wrote then, "That article about the Toshiba device makes no mention of the type of nuclear fuel, or even the type of nuclear reaction (fusion or fission) involved ... unless they're implying that lithium-6 is the fuel."

Using lithium-6 as a nuclear fuel (in fusion) would be much more difficult than using hydrogen or helium, which AFAIK is what all existing fusion test plants use. The idea that it is currently feasible, let alone economical or possible in the supposed small-scale Toshiba device, is ludicrous.

By saying "the new micro reactor uses no control rods to initiate the reaction", the writer is betraying either ignorance or very sloppy writing. Control rods (in a fission reactor) don't initiate anything -- by absorbing neutrons they slow down or prevent chain reactions. [I]Withdrawing[/I] control rods is something that would be done at a fission reactor to allow chain reactions to start or increase. Of course, that quote could also be a (very sloppy) way of saying that the reactor is a fusion reactor, rather than fission, but see above about fusion.

Also, how is "lithium-6, an isotope that is effective at absorbing neutrons" supposed to be a fuel? As I said, absorbing neutrons is what the control rods in fission reactors are supposed to do! Lithium might conceivably be used as a moderator around the fuel rods of a fission reactor, but not as the fuel itself (unless in a fusion reactor -- but see above)!

"there's nothing that can really happen because the power produced is so low that none of the general problems can happen" Well, most small lumps of natural uranium ore sitting on shelves produce very low power but not much problem. But if the power is so low that no "general" problem can happen, then it's so low that it wouldn't be of any use in a power-generation device!

Jwb52z, I stand by everything I said about [URL="http://www.nextenergynews.com/"][COLOR=#22229c]www.nextenergynews.com[/COLOR][/URL]. Its two supposed descriptions of small nuclear power devices are just hoakum and bunkum.

[QUOTE=cheesehead;134906]Also, how is "lithium-6, an isotope that is effective at absorbing neutrons" supposed to be a fuel? As I said, absorbing neutrons is what the control rods in fission reactors are supposed to do! Lithium might conceivably be used as a moderator around the fuel rods of a fission reactor, but not as the fuel itself (unless in a fusion reactor -- but see above)![/QUOTE]These designs for micro-reactors have been around for at least 30 years that I know of. I have no more inside information about the Toshiba design than anyone else here but I can make some pretty good guesses.

First off, Li-6 is [b]not[/b] a fuel. It's exactly what theadvert says --- a moderator.

Secondly, every design I've yet seen uses slightly enriched U-235 as fuel.

Third, they are intrinsically safe in the sense that they have to be kept continually under control to generate any uesful power. If the cooling system fails, or the control circuitry loses power, or if anything overheats, a liquid moderator (Li-6 in this design) pours into the core under gravity and quenches the reaction. The low enrichment is a crucual part of this design because it makes them quite hard to get useful amounts of fission in the first place.

Fourth, these things are really quite small. They are a few cubic metres, weigh a few tons and would typically be buried under your back yard. Power output is a few tens of kilowatts to perhaps 200kW for the big model. About the power of a beefy diesel backup generator in other words.


Paul

Umm, with a lithium-6 moderator, why isn't this an efficient tritium factory?

[URL]http://www.cnn.com/2008/TECH/science/05/30/space.solar/index.html[/URL]

[SIZE=1](Asimov's robot stories were always a favorite of ours.)[/SIZE]

[QUOTE=only_human;134486]While watching C-Span, I learned that President Bush made light-water reactor program and enriched uranium supply aggreements in Saudi Arabia. [URL="http://news.yahoo.com/s/afp/20080516/pl_afp/mideastusdiplomacybushsaudideals"]US unveils deals with Saudi on nuclear power, oil protection[/URL]

Nuclear Energy seems to me to be a active topic these days for many reasons and it was a bit surprising to not find a thread on it in the Soap Box.

My feelings about nuclear issues are a bit overwhelmed with concerns of radioactive wastes.[URL="http://en.wikipedia.org/wiki/Radioactive_waste"]http://en.wikipedia.org/wiki/Radioactive_waste[/URL][/QUOTE]

Oh, I [B]so[/B] have to comment on this today. Not to get sidetracked in political issues, I didn't get into the irony of initiating the sending enriched uranium to Saudia Arabia while concerned about uranium use in Iran. There is an all-or-nothing kind of thinking that collapses all fuzzy knowledge about nations into a binary friend (safe) or enemy (possibly a war target) determination. Be that as it may, today --- today, I've read more about this careless, additional assumption of risk thinking that drives me to speak:[QUOTE]“I would seek to establish an international repository for spent nuclear fuel that could collect and safely store materials overseas that might otherwise be reprocessed to acquire bomb-grade materials. It is even possible that such an international center could make it unnecessary to open the proposed spent nuclear fuel storage facility at Yucca Mountain in Nevada.”

— John McCain, 5/27/08[/QUOTE][URL="http://www.lasvegassun.com/news/2008/may/28/mccains-about-face-yucca/"]McCain’s about-face on Yucca[/URL] This is both "send our trash elsewhere so we don't have to look at it" and "we can manage the risks of doing something because we are so smart and have no foibles" kind of thinking. This won't do. Nope.

[quote=xilman;134951]First off, Li-6 is [B]not[/B] a fuel. It's exactly what theadvert says --- a moderator.[/quote]Well, that's my [I]guess[/I], too. But the linked article doesn't have the character string 'moderat'.

[quote]Secondly, every design I've yet seen uses slightly enriched U-235 as fuel.[/quote]... but the article makes no mention of fuel at all, and I don't see that the context makes it clear, so I view that article as suspiciously lacking in crucial information.

[quote=fivemack;134958]Umm, with a lithium-6 moderator, why isn't this an efficient tritium factory?[/quote]Yes, I too am curious about what these designs do with the tritium and helium buildup in the moderator.*

* - I haven't looked up whether the uranium core is emitting fast or slow neutrons.

From [URL]http://hyperphysics.phy-astr.gsu.edu/Hbase/NucEne/fusion.html[/URL]:

Li-6 + slow neutron -> He-4 + H-3 + 4.8 MeV

Li-7 + fast neutron -> He-4 + H-3 + slow neutron

[QUOTE=cheesehead;135066]Yes, I too am curious about what these designs do with the tritium and helium buildup in the moderator.*[/QUOTE]I just did a little bit of online reading and from what I can tell, and I know nothing about nuclear reactor construction, it would be ok to just let the tritium and helium escape into the air. Tritium is basically harmless according to what I read, except for a low level of beta radiation. I mean, the reading I did even said that the upper atmosphere converts some hydrogen to tritium and water and we're not suffering any side effects if it happens all the time. Could we be getting rained on by liquid tritium that's formed water with oxygen? It's supposedly more commonly a liquid than a gas as well, so maybe. Even if large quantities had to be taken away somewhere, you can use tritium to make things like self-powered clocks. Helium, as far as I can tell, doesn't hurt anyone ever.

[quote=Jwb52z;135292]it would be ok to just let the tritium and helium escape into the air.[/quote]Yes, but the problem is really the lithium moderator in which they're swimming. It (lithium) would burn upon contact with air, so it's not a matter of just having a simple escape valve. :-)