Future Energy Sources....

[coreview2]

Beyond intermittent sources, efficiency and conservation savings, we still have to have very solid base power. Given the coming emergence of primarily electric drive vehicles, a lot more electric power will be needed.

 

My sense is that base power should come from two new sources.

 

1. Meltdown proof pebble-bed nuclear reactors are one viable answer that I'm amazed has not been "discovered" by the lawyers or others in Congress. They are about 50% efficient, truly meltdown proof, and because they use helium as the heat exchange medium they greatly reduce radioactive waste. It is a very elegant design.

 

2. Magma heat mining. 99% of our planet is above 1000C and most of the world's crust is around 5KM thick (see the USGS chart below). The world's deepest holes drilled are around 12KM and there are thousands in the 5KM range. The basic concept is to put a pipe loop directly into liquid magma as a heat exchanger in a binary power plant or to use for thermochemical hydrogen production (50%+ efficient).

 

There is nothing really new in the technology except that drilling with laser is int the near future with great promise and seismic imaging allows us to "see" ideal locations.

 

There are many places like along the 70,000KM of tectonic rifts where new crust is forming constantly, that Earth's crust is very thin.

 

Magma heat mining would dwarf all other sources except Mr. Fusion. It would have a very small environmental footprint, no emissions and no waste to dispose of.

 

 

crustal thickness

[SkepticLance]

Just pointing out the obvious from the proferred map.

Most of the thin crust is under the deep ocean, making drilling very difficult, and the crust over most of the world's land masses is 25 km or more in thickness.

[swansont]

1. Meltdown proof pebble-bed nuclear reactors are one viable answer that I'm amazed has not been "discovered" by the lawyers or others in Congress. They are about 50% efficient, truly meltdown proof, and because they use helium as the heat exchange medium they greatly reduce radioactive waste. It is a very elegant design.

 

How do they reduce waste, exactly?

[insane_alien]

they don't they just make it slightly easier to manage.

[YT2095]

IIRC, when I was researching these, they`re Recycled, but I don`t rem the exact method.

[coreview2]

Just pointing out the obvious from the proferred map.

Most of the thin crust is under the deep ocean, making drilling very difficult, and the crust over most of the world's land masses is 25 km or more in thickness.

 

While that is true, if you note, there are plenty of places where the crust is 0 to 5KM thick and there are places like Iceland where very thin crust (plate rift) runs right under it.

 

Given the vast scale of the "blue" (5KM) part of the global crustal chart, do you not think that seismic imaging could not find some very choice spots?

 

Interestingly, while reading up on drilling, there are deep gas wells in the US that have hit molten material. Perhaps this is a case of functional fixedness, but it is ironic that an energy company finds a trove of energy (molten material), but it's not NH4, so its bad news. There is a major disconnect there somewhere.

 

How do they reduce waste, exactly?

 

Because the designs use helium as an exchange medium and helium as an inert gas cannot become radioactive. In light water reactors, water itself becomes a very large quantity of low-level radio active waste.

 

http://gt-mhr.ga.com/

 

 

At the start of the 21st century, most of the electricity consumed in the U.S. and the rest of the world is still being generated by the burning of fossil fuels. Even larger quantities of fossil fuels are being burned to meet other demands imposed by the residential, commercial, industrial, and transportation sectors. In 1999, the U.S. imported 58% of its crude oil and 37% of its total energy supply, and burning fossil fuels in the U.S. resulted in the emission of 11.3 million metric tons of sulfur dioxide, 4.9 million metric tons of nitrogen oxide, and an astounding 1510 million metric tons of carbon dioxide. It is clear that a new energy policy must address these environmental, economic, and energy-security concerns. With recent technological advances, a strong case can be made to include nuclear energy as a major component of a 21st-century energy policy.

 

The GT-MHR combines a meltdown-proof reactor and advanced gas turbine technology in a power plant with a quantum improvement in thermal efficiency. . . approaching 50%. This efficiency makes possible much lower power costs, without the environmental degradation and resource depletion of burning fossil fuels

 

Efficiency from thermodynamics

 

Conventional, low-temperature nuclear plants operate at about 32% thermal efficiency. GT-MHR power plants can achieve thermal efficiencies of close to 50% now, and even higher efficiencies in the future.

 

• 50% more electrical power from the same number of fissions.

 

• Dramatically lower high-level radioactive waste per unit of energy – today’s reactors produce 50% more high-level waste than will the GT-MHR.

 

• Much less thermal discharge to the environment. Plants can use air cooling, which allows for more flexible siting options.

[SkepticLance]

What Wiki has to say on the subject

 

http://en.wikipedia.org/wiki/Pebble_bed_reactor

 

"The pebble bed reactor (PBR) is a type of nuclear reactor.

 

The design aims to achieve lower risks and higher thermal efficiencies than possible in traditional nuclear power plants. Instead of water, it uses pyrolytic graphite as the neutron moderator, and an inert or semi-inert gas such as helium, nitrogen or carbon dioxide as a means to cool the reactor and to directly drive a turbine. This eliminates the complex steam management system from the design and increases the thermal efficiency (ratio of electrical output to thermal output) from 32-35% to 40-50%. Also, the gases do not dissolve contaminants or absorb neutrons as water does, so the core has less in the way of radioactive fluids and is more economical than a light water reactor.

 

A number of prototypes have been built, and it is currently under active development in South Africa as the PBMR design, and in China whose HTR-10 is the only prototype currently operating."

[swansont]

Because the designs use helium as an exchange medium and helium as an inert gas cannot become radioactive. In light water reactors, water itself becomes a very large quantity of low-level radio active waste.

 

http://gt-mhr.ga.com/

 

That's mainly Tritium, though, right? Your link does not explain this at all, it just states that "Dramatically lower high-level radioactive waste per unit of energy – today’s reactors produce 50% more high-level waste than will the GT-MHR" so it's talking about high-level waste, not tritiated water, which you agree is low-level waste.

 

So I ask again, how is less high-level waste being achieved? Is this simply an artifact of having a higher thermal efficiency, so there is less waste per MW-hr of operation. The numbers seem to indicate this (thermal efficiency and waste improvements being basically identical)?

 

(and typically the phrase "inert gas" refers to Helium's chemical properties. Inert gases in general can most certainly become radioactive. Chemical inertness does not imply nuclear stability)

[coreview2]

What Wiki has to say on the subject

 

 

A number of prototypes have been built, and it is currently under active development in South Africa as the PBMR design, and in China whose HTR-10 is the only prototype currently operating."[/i]

 

I don't like the South African design because unlike the General Atomics design the pebbles or gum-balls are not ceramic coated. They just presume that no air in the thing keeps it fireproof. The GA version really is meltdown proof because it doesn't matter if air gets into the chamber or if the chamber spills out. However, if I'm reading it right, the South African one could have a major Chernobyl like event given air leaking into it, something like a terrorist attack or big human error. The Russian reactors used graphite as the modulator also and Chernobyl was what happened when the graphite and core got exposed to air.

 

Someone please correct me if I'm wrong or overly vague on the details.

 

That's mainly Tritium, though, right? Your link does not explain this at all, it just states that "Dramatically lower high-level radioactive waste per unit of energy – today’s reactors produce 50% more high-level waste than will the GT-MHR" so it's talking about high-level waste, not tritiated water, which you agree is low-level waste.

 

So I ask again, how is less high-level waste being achieved? Is this simply an artifact of having a higher thermal efficiency, so there is less waste per MW-hr of operation. The numbers seem to indicate this (thermal efficiency and waste improvements being basically identical)?

 

(and typically the phrase "inert gas" refers to Helium's chemical properties. Inert gases in general can most certainly become radioactive. Chemical inertness does not imply nuclear stability)

 

 

Good questions. Beyond what's available on the web, most of what I know on the GA design is from a nuclear engineer that passed through the NYTimes science forums a few years back and it is my understanding that most of our waste volume is low-level waste.

 

Is there a radioactive helium? I don't know.

 

I do like the elegance of General Atomics design however. The inherent meltdown proof nature of the plant should mean that they are ultimately a lot cheaper to build and operate and politically the safety factor eliminates about 90% of reservations about nuclear power.

[swansont]

I don't like the South African design because unlike the General Atomics design the pebbles or gum-balls are not ceramic coated. They just presume that no air in the thing keeps it fireproof. The GA version really is meltdown proof because it doesn't matter if air gets into the chamber or if the chamber spills out. However, if I'm reading it right, the South African one could have a major Chernobyl like event given air leaking into it, something like a terrorist attack or big human error. The Russian reactors used graphite as the modulator also and Chernobyl was what happened when the graphite and core got exposed to air.

 

Someone please correct me if I'm wrong or overly vague on the details.

 

Meltdown-proof and fireproof are two separate issues. Meltdown-proof implies that the decay heat (energy from the decay of the fission products) is insufficient to melt the fuel elements. Fireproof means just that, and is protection against particulates from actual combustion.

 

The ceramic coating is presumably not combustable, so as long as their integrity is not compromised you won't get a release of contamination.

 

 

Is there a radioactive helium? I don't know.

 

The answer to that is yes, but in a trivial fashion. He-4 can very occasionally absorb a neutron to become He-5, which decays ... by neutron emission. And quite rapidly. It's just that in general it's probably better to not mix nuclear- and chemical-reaction terminology.

[SkepticLance]

It is probably worth noting that the pebble bed reactor is not the only novel design available. A while ago I read of a reactor based on a cylinder of fuel, too thin to permit ongoing nuclear fission, since too many neutrons escaped. The system was to use a cylinder of material that reflected neutrons. This wrapped around the fuel element and induced fission by reflecting neutrons back into the core. As the fuel elements were used up, the reflecting cylinder was simply raised up the core to reflect neutrons into unused fuel core.

 

The whole thing, because of its shape would be placed inside a 'well' - a deep hole in the ground for security and safety. The added safety feature was that the reflecting cylinder could be dropped at any stage to below the fuel core. This type of reactor could be designed to generate lower levels of energy, and could be used as generator for a small town or even a large factory.

 

An even smaller system is being offered by Toshiba from Japan, using a kind of reverse process, with a neutron absorbing cylinder inside the fuel cylinder.

 

http://www.nextenergynews.com/news1/next-energy-news-toshiba-micro-nuclear-12.17b.html

[coreview2]

It is probably worth noting that the pebble bed reactor is not the only novel design available. A while ago I read of a reactor based on a cylinder of fuel, too thin to permit ongoing nuclear fission, since too many neutrons escaped. The system was to use a cylinder of material that reflected neutrons. This wrapped around the fuel element and induced fission by reflecting neutrons back into the core. As the fuel elements were used up, the reflecting cylinder was simply raised up the core to reflect neutrons into unused fuel core.

 

The whole thing, because of its shape would be placed inside a 'well' - a deep hole in the ground for security and safety. The added safety feature was that the reflecting cylinder could be dropped at any stage to below the fuel core. This type of reactor could be designed to generate lower levels of energy, and could be used as generator for a small town or even a large factory.

 

An even smaller system is being offered by Toshiba from Japan, using a kind of reverse process, with a neutron absorbing cylinder inside the fuel cylinder.

 

http://www.nextenergynews.com/news1/next-energy-news-toshiba-micro-nuclear-12.17b.html

 

 

 

I guess I'd worry about any system with the potential for very high risk that relies on intervention to make it stop. Systems fail. People fail.

 

If I understand the GA pebble-bed (gum-ball machine) correctly, no matter what happens it cannot meltdown, or burn. If it is left sitting there with the switch on and all loss of coolant/heat exchanger, it will not melt-down or release anything.

 

I think this is politically very important.

 

I also like the potential of the gum-ball machine refueling. The balls are churned and randomly tested so when they are spent, the "pin-ball" machine drops them out and a new ball is added.

 

Very elegant concept.

[SkepticLance]

To coreview

 

You are correct about the elegance of the pebble bed design. Just that 'one size fits all' is not a good philosophy, and it may be that other designs are better for other circumstances. For example ; Toshiba have offered their design to a small Alaskan town that relies on diesel generators since they are too isolated to be connected to the grid. The Toshiba mini system would be great for isolated communities and businesses which do not want to burn diesel.

 

The other system I mentioned has an exchangeable core. One fuel core will last perhaps 20 years, and can be lifted out in its entirety for disposal, and another core dropped into place. The neutron reflecting cylinder provides a safety factor as good as the pebble bed system, since any failure causes the system to automatically 'let go' of the cylinder, which falls back to the base of the fuel cyclinder - the part with no fissionable material - thus stopping the reaction.

[YT2095]

I think part of the fireproof aspect is its "immunity" to the wigner effect.

[coreview2]

To coreview

 

You are correct about the elegance of the pebble bed design. Just that 'one size fits all' is not a good philosophy, and it may be that other designs are better for other circumstances. For example ; Toshiba have offered their design to a small Alaskan town that relies on diesel generators since they are too isolated to be connected to the grid. The Toshiba mini system would be great for isolated communities and businesses which do not want to burn diesel.

 

The other system I mentioned has an exchangeable core. One fuel core will last perhaps 20 years, and can be lifted out in its entirety for disposal, and another core dropped into place. The neutron reflecting cylinder provides a safety factor as good as the pebble bed system, since any failure causes the system to automatically 'let go' of the cylinder, which falls back to the base of the fuel cyclinder - the part with no fissionable material - thus stopping the reaction.

 

Oh don't get me wrong, I don't think one-size-fits-all is anything other than a classic government-like mistake, but I think the criteria should always be that the thing is literally melt-down proof, fire-proof, idiot-proof and unattractive to terrorists as well.

 

I saw some Thorium breeder directions that were interesting too. The fail-safe in that direction is melting plugs that drain the chamber. Still the ceramic coated pebble-bed's great appeal is that civilization could fall into the dark ages and the plant left unattended without catastrophic consequences. In any event, it appears to be a good place to start as it is a very politically viable concept completely purged of political clouds of Chernobyl or even Three Mile Island.

[coreview2]

Anyone have any other suggested new sources of energy that would qualify as both clean and baseline power (non-intermittent, reliable and sustainable too).

 

I'm not sure Mr. Fusion is going to happen any time soon as a practical matter and the process does produce radioactive waste.

[iNow]

Solar coupled with high energy density battery banks.

[SkepticLance]

I agree with coreview that nuclear fission must become more and more important, whether using pebble bed technology or some other form. Deep geothermal will, I think, be more limited to certain geographic areas, such as Iceland.

 

Here in New Zealand, a pilot project is under way to mount enormous propellers inside Cook Strait to run on the very substantial tidal flow. Tidal power has the potential to supply my country's future needs for at least the next 50 years.

 

Wave power is probably the most energy rich of all 'renewable' sources. Once the bugs are out of the system (main bug being that the frequent '100 year' storms tend to wreck the entire wave power plants) this can supply a very large part of the entire world's power needs.

[coreview2]

I agree with coreview that nuclear fission must become more and more important, whether using pebble bed technology or some other form. Deep geothermal will, I think, be more limited to certain geographic areas, such as Iceland.

 

Here in New Zealand, a pilot project is under way to mount enormous propellers inside Cook Strait to run on the very substantial tidal flow. Tidal power has the potential to supply my country's future needs for at least the next 50 years.

 

Wave power is probably the most energy rich of all 'renewable' sources. Once the bugs are out of the system (main bug being that the frequent '100 year' storms tend to wreck the entire wave power plants) this can supply a very large part of the entire world's power needs.

 

As long as the reactors are truly meltdown proof, idiot proof and unattractive to terrorists, they should have big role.

 

I like wave power but not too many of the designs I've seen. The best concept I've seen so far was a simple float anchored to the bottom with the up and down motion driving a generator.

 

However, magma heat mining has vast potential that dwarfs all others. While most of Earth's crust is 5KM thick, there is quite a bit that is much less and if you are making hydrogen it doesn't really matter if it is real close to the market. While a lot of the very thin crust is not ideally located near major cities, a good bit of it is within transmission range much as NY gets a lot of power from Canada. Super conductors would be a big help!

 

Then too the technological means of seeing geology with seismic imaging is quite advanced and would be likely to find some choice spots as close as possible to electric consumptions markets.

[Mr Skeptic]

Anyone have any other suggested new sources of energy that would qualify as both clean and baseline power (non-intermittent, reliable and sustainable too).

 

OK, here's one, but it has a very large if... If we are able to create tiny black holes, and if Hawking radiation exists (I don't think it has been observed yet, though scientists are quite sure it exists), then we would have a power source that could use any matter as fuel, and produce no radioactive wastes. It would be a little dangerous, perhaps, but very useful.

[CaptainPanic]

I agree with iNow (#17). Solar power and batteries (or another energy storage) are a perfect option. The benefit of having electricity and storage is that you can generate the power about everywhere on earth.

 

Independent energy supply is important, and will be more important in the future. Therefore I believe that using volcanoes will not be a proper solution for everyone, although I think it would be a wonderful solution for many...

 

I don't like nuclear power because I have yet to see the final solution for the waste it creates. Higher thermal efficiency is all nice, but it is the same argument why the world is building new coal powered plants. It's only an increase of 60% or so (impressive, but solar is doing better when seen over the last two decades). I'd like to see a higher efficiency in fuel consumption. It's been speculated that the new fourth generation nuclear powered plants can do this... but none were built so far... Therefore, the waste generated remains the same problem it has been for some decades. We're only beginning to permanently store the waste from the sixties (it has been in temporary storages for a while now). In fact, we're still paying for the storage of the energy of the sixties. But my main argument against nuclear is not a financial one, it is the fact that no human made structure has survived more than about 5000 years. Storage is all nice, but I don't believe we're capable of building any structure that is indestructible for the next hundred millennia.

[swansont]

if you are making hydrogen it doesn't really matter if it is real close to the market.

 

On the contrary, I think you'll find that Hydrogen doesn't pipe very well (hydrogen embrittlement), nor does it liquify particularly easily, and without significant pressure, the energy content per unit volume is too small to transport economically. This tends to point to on-demand production at the place it will be used.

[SkepticLance]

To swansont

 

There was a major article in Scientific American (July 2006, page 59) about liquifying hydrogen and sending it down a pipeline. The twist was that the pipeline was made of aluminium and was also used as a superconducting conduit for electric power. Naturally the whole had to be VERY heavily insulated - against heat and electricity. The authors were suggesting the system as a whole national grid.

 

I do not know how practical or likely the idea is, but the SciAm authors are usually very expert in their field.

[iNow]

It seems silly to transport energy over long distances if the option exists to generate it locally... This idea applies regardless of which technology is responsible for that generation. I see localized energy generation via multi-modality techniques being a very powerful way to help us out of this abysmal situation in which we currently find ourselves with our reliance on earth destroying grossness. (yes, that's the technical term).

[coreview2]

On the contrary, I think you'll find that Hydrogen doesn't pipe very well (hydrogen embrittlement), nor does it liquify particularly easily, and without significant pressure, the energy content per unit volume is too small to transport economically. This tends to point to on-demand production at the place it will be used.

 

If you look at history you will find that we did indeed handle hydrogen for many decades in the form of Town Gas or Coal Gas. Town Gas is a mixture of hydrogen and carbon monoxide resulting from cracking coal and it was used for cooking, heating and lighting up until the early 1950's.

 

For the last decade or so, all new gas pipelines have had to be hydrogen ready by federal law.

 

The last coal gas plant in the US Northeast shutdown in 1955.

 

From what I've read in studies on that side of the topic, hydrogen does pose problems for delivery and transport, but they are neither impossible nor uneconomical. This is in part due to the presumed use of hydrogen in fuel cells where efficiency is very high and not burning it in very inefficient internal combustion engines.

 

It takes about 1/3 of the energy delivered to convert hydrogen to LH2.