Nuclear Power versus Hydrogen Power

[Sea Skimmer]

The fuel cells that would be required to generate the hydrogen, just based on the platinum cost, would most likely be far more expensive than nuclear plants and would require more intensive precious metals mining.

You are confused. Fuel cells don’t make hydrogen, they are a low pollution/few moving parts method of turning it back into electricity. You can also just burn hydrogen in conventional internal combustion engines, the only hardware change required being hydrogen fuel injectors which can be retrofitted to any existing car or truck including those which are still carbureted. Storing hydrogen is a serious problem but people are currently working on systems which would store it dissolved inside of liquids (rather then liquefying the hydrogen proper), with the hydrogen released on demand via a very small electric current. As I recall a system which could store it as a non frozen solid is also under development.

[Shroom Man 777]

Could jet aircraft, including military planes, use these hydrogen fuels?

[Mr Bean]

Could jet aircraft, including military planes, use these hydrogen fuels?

If an oil tank or even a jet fuel tank gets puncture it can be repaired, heck we've had self sealing fuel tanks since World War II. Such a self sealing tank might not be possible with current under high pressure hydrogen tanks. And Fuel cells might face weight issues for plane installation.

It all comes down to if a fuel cell can pack in just as much power as the onboard engine can produce.

[Starglider]

It all comes down to if a fuel cell can pack in just as much power as the onboard engine can produce.

There would be no reason to use a fuel cell on a jet or turboprop aircraft, except possibly as an APU (assuming a bleedless design e.g. the 787). The only place you might use a fuel cell would be for a light aircraft that doesn't merit the expense of a turboprop and would get more range and reliability (maybe) out of a fuel cell plus motor than out of a hydrogen IC engine.

[Marcus Aurelius]

You cost projects have to take that kind of thing into account. Yes superconducting grid is a fine idea, but the extra cots for the thicker wires, the requirement to bury them, the costs of maintaining them must be factored in if you want to have a realistic idea of how much money such a grid would cost VS keeping our old grid(Even burying it anyway) and putting a plant outside every large city or town, and rebuilding our entire electrical system and building in enough backups for our solar power to work.

When you say "conventional grid" do you mean conventional AC or have you included HVDC as well? With HVDC it is feasible to do several thousand kilometer long transmissions. Superconducting grid would still be needed for really long distances, but HVDC currently (i.e. no future tech) scales to more than 2,000 kilometers if needed.

[sketerpot]

I had watched a science channel program recently that talked about developments on solar cells that increase their efficiency by some large amount. I forgot the name and guy who was doing it but he's working and testing his project in Australia. Anyone with knowledge in this, would this still require gigantic arrays of solar panels to sufficiently provide power for the US?

There's always someone working on higher solar cell efficiency, and it's impressive, but, their press releases never mention efficiency degradation or manufacturing. And those are some really important issues with solar cells. It doesn't matter if you get some 40% efficient multi-junction nano-wowie wonder-cells if they cost 20 times more than regular solar cells and wear out after a few months. Which is fairly typical.

When you say "conventional grid" do you mean conventional AC or have you included HVDC as well? With HVDC it is feasible to do several thousand kilometer long transmissions. Superconducting grid would still be needed for really long distances, but HVDC currently (i.e. no future tech) scales to more than 2,000 kilometers if needed.

Now that the cost of high-voltage AC/DC converter hardware has come down a bunch, HVDC is becoming kind of a big deal. And I predict it will become a bigger deal in the next decade because of new power line materials that have much greater tensile strength without significantly increased resistivity, so they can carry a lot more current per wire, but which can only work well with DC because of hysteresis losses with AC. This is set to bring the costs of high-capacity HVDC power transmission down quite a bit by reducing the number of transmission lines you have to build. In other words, except for niche applications (or unless there are superconductor breakthroughs), superconducting power grids are toast.

They also argue that nuclear power is unsustainable

Known uranium reserves are already sufficient to last thousands of years (with reprocessing), and that's without further exploration, uranium extraction from seawater, or fusion.

Or breeder reactors. Or thorium, which is several times more abundant than uranium.

[Sea Skimmer]

Could jet aircraft, including military planes, use these hydrogen fuels?

Hydrogen, biofuels and methane have been tested in subsonic jet turbines and work well. However they have not been tested on any significant scale in engines capable of supersonic speed as we find on fighters and some bombers. Militaries are much more interested in biofuel then compressed gas fuels because they can run in existing fuel systems and engines with few modifications, while you’d need entirely new hardware to run a gas fuel.

[Hawkwings]

What kind of energy densities can you get with hydrogen fuel, compared to gasoline and jet fuel? I imagine this would be a big issue for airplanes especially.

[Mayabird]

If we have to shoot sulfur particles into the stratosphere to counter global warming, those solar panels aren't going to work well at all with the reduced sunlight, though if we would freaking go to replacing coal plants with nuclear and building even more of them too, we might not have to resort to the sulfur at all.

Hydrogen fuel cells without nuclear would work in Iceland where they have a small population and ample hydroelectric and geothermal power, but they're a special case in that regard. Also now they're worse than broke.

[Surlethe]

If we have to shoot sulfur particles into the stratosphere to counter global warming, those solar panels aren't going to work well at all with the reduced sunlight, though if we would freaking go to replacing coal plants with nuclear and building even more of them too, we might not have to resort to the sulfur at all.

I'm not sure that's a justifiable assertion without determining just how much this sulfur scheme would reduce surface insolation. After all, if you need only a 2% reduction in surface insolation to reverse warming, that's not going to significantly affect the ability of solar panels to collect energy.

[Darth Wong]

Now that the cost of high-voltage AC/DC converter hardware has come down a bunch, HVDC is becoming kind of a big deal. And I predict it will become a bigger deal in the next decade because of new power line materials that have much greater tensile strength without significantly increased resistivity, so they can carry a lot more current per wire, but which can only work well with DC because of hysteresis losses with AC. This is set to bring the costs of high-capacity HVDC power transmission down quite a bit by reducing the number of transmission lines you have to build. In other words, except for niche applications (or unless there are superconductor breakthroughs), superconducting power grids are toast.

I think people are in love with the idea of superconducting power grids just because of the coolness factor. It doesn't help that there's misleading terminology, like "high temperature superconductors", by which they actually mean they can be cooled with liquid nitrogen instead of something even colder.

[Marcus Aurelius]

Hydrogen fuel cells without nuclear would work in Iceland where they have a small population and ample hydroelectric and geothermal power, but they're a special case in that regard. Also now they're worse than broke.

The whole idea of hydrogen replacing oil based fuels on a large scale, regardless of the actual energy production method, is definitely still depended on untested and experimental technologies, which might amount to nothing in the end. Wide scale electrolysis of water and storage of hydrogen pose significant difficulties, which might take longer to solve than practical fusion power. Therefore the so called "hydrogen economy" is what I call a "techno-fix wet dream". It is not something we can rely on in the near or medium term, just like fusion. Of course there are promising solutions suggested to the aforementioned problems with hydrogen, but there are always promising technologies in the early stages of development. Most of them do not fulfill their initial promises.

So for the time being it will have to be hybrid and battery-powered electric vehicles, more and better railroads to replace long distance driving and perhaps small nuclear reactors for ships. Air traffic is still a major problem. It will probably contract a lot and once again become financially possible only for the well-off, unless something like 3th generation biofuels (algae etc.) can actually made to work on an industrial scale. At the moment I would not get my hopes up with them either.

[Starglider]

It doesn't help that there's misleading terminology, like "high temperature superconductors", by which they actually mean they can be cooled with liquid nitrogen instead of something even colder.

Why, what would you call them? 'Somewhat less low temperature superconductors' doesn't exactly roll off the tounge.

[Ryan Thunder]

It doesn't help that there's misleading terminology, like "high temperature superconductors", by which they actually mean they can be cooled with liquid nitrogen instead of something even colder.

Why, what would you call them? 'Somewhat less low temperature superconductors' doesn't exactly roll off the tounge.

Liquid Nitrogen-cooled superconductors, or nitrogen-cooled superconductors, for short. Still has very cold connotations.