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[Tellemurius]

That'd be a CANDU, right?
They use deuterium oxide and are pretty cool.

Yup. Suck that Iran, no bombs.

I don't think the solar thing will work, because it isn't always sunny. And the amount of pollution and GHGs produced creating the battery is the same as the amount produced by a conventional car in ~5 years.

Personal batteries, yes. Large scale operations do not use chemical batteries, instead other, more cost-efficient systems. For instance, pumping water up during the day and generating power hydroelectrically at night. Also, I understand that molten salt solar systems work by melting salt and using that to boil water. The heat is supposedly so intense it can operate for twelve hours without sunlight.

Molten Sodium and they last for 3 days without light ^_^

[malimbar04]

Not only can we make our own oil, but the if we are thinking of the same algae, then it takes carbon dioxide from the atmosphere to produce the oil, so if you burnt 100% of produced oil, you would be carbon neutral, and if you missed even a single drop you would be off setting the current problem. Bio solar power to the rescue!

Yup, we're thinking of the same stuff. It's the invention that cal allow us to keep our dirty oil habit for all of time!

Or, if we ever get super capacitors to have the same charge/weight ratio as current batteries, we'll just switch to electric everything. Electric engines are freaken awesome and are only held back because of battery technology.

[Nadaka]

That'd be a CANDU, right?
They use deuterium oxide and are pretty cool.

Yup. Suck that Iran, no bombs.

I don't think the solar thing will work, because it isn't always sunny. And the amount of pollution and GHGs produced creating the battery is the same as the amount produced by a conventional car in ~5 years.

Personal batteries, yes. Large scale operations do not use chemical batteries, instead other, more cost-efficient systems. For instance, pumping water up during the day and generating power hydroelectrically at night. Also, I understand that molten salt solar systems work by melting salt and using that to boil water. The heat is supposedly so intense it can operate for twelve hours without sunlight.

Molten Sodium and they last for 3 days without light ^_^

Molten salt isn't burning exploderation like hot sodium can be, so not really sure if sodium is ideal. And the duration will vary by the size of the reservoir and its insulation. The good news is that larger reservoirs are actually more efficient because the surface area is proportionally less. That means the difference between a 12 hour reservoir and a 3 day reservoir is just a matter of engineering.

[Tellemurius]

The Sodium system is sealed >_>

[Nadaka]

The Sodium system is sealed >_>

molten salt systems are also closed.

If the system leaks, the salt itself won't burn the way sodium can. And you may want to think twice about spraying water on a sodium fire...

[Tellemurius]

Durr >_>

[Lemunde]

There's always fusion power. It's coming but not soon enough. Pretty much the problem with all forms of renewable energy is there isn't enough time or resources to get enough facilities operational to be able to supply the energy needs currently being produced by non-renewable sources.

[Nadaka]

There's always fusion power. It's coming but not soon enough. Pretty much the problem with all forms of renewable energy is there isn't enough time or resources to get enough facilities operational to be able to supply the energy needs currently being produced by non-renewable sources.

Always includes the immediate future. Controlled fusion over unity is still hypothetical for the time being. Solar and fission power (plus a handful of others to suppliment) can be done now.

[PTTG??]

Then there's switching to less energy-intensive lifestyles. Like budget reform, merely increasing income or merely decreasing expenses doesn't cut it, you need both.

Personal transportation and industrial shipping are one of the largest energy users.

I wonder if a Panamax-type cargo ship could run off on-deck solar, assuming it had good batteries. It's known that they burn the lowest grades of fuel while at sea since it's so cheap, then switch to regular grades once they enter national waters.

In the US, the rail systems have been butchered for being too efficient or something. Rebuilding the network would be tough and expensive, but would increase efficiency.

A relatively small issue, but still significant, is personal transportation. Suburbia is a historic mistake. Walkable communities, designed so that you can get through a whole day without starting a car, were once the norm, and will have to be again.

There are working fusion reactors that while below unity at current scale, could in theory generate net energy, with superconductors and ten times the size. Check out the Polywell project.

[Nadaka]

Counting the US, Europe and the wealthier parts of the rest of the world, about 15% of people live with a more or less "western" standard of living. The other 5/6ths of the planet are desperately trying to reach parity with us.

No amount of conservation and efficiency by that 15% is going to matter all that much as the energy budget of the rest of the world balloons up.

I am not saying it is a bad idea, just that it isn't a solution.

Solar shipping isn't possible, to much mass, not enough surface area. There are some people considering using fully autonomous sailing ships to navigate the pacific at much slower speeds than modern ships. But for fast massive ships like you mentioned? Nuclear power is probably the only alternative to diesel for the foreseeable future.

[Soadreqm]

The Sodium system is sealed >_>

If you're not worried about sealed systems suddenly becoming unsealed, you might as well go with nuclear fission.

[PTTG??]

The Sodium system is sealed >_>

If you're not worried about sealed systems suddenly becoming unsealed, you might as well go with nuclear fission.

Well put. Still, even exploding sodium is better than exploding uranium, and you'd probably build these things in Nevada, where a few acres of molten, burning metal would not seem out of place.

@Nakada:
I don't know why, but naval reactors seem to have a better history than installations. Perhaps it's because failed naval reactors are generally state secrets, and perhaps it's because of military precision in maintenance. Still, I'm not exactly comfortable with an easily-pirateable boatful of nuclear fuel floating around, and having private citizens operate the reactor isn't pleasing either.

[Virex]

That'd be a CANDU, right?
They use deuterium oxide and are pretty cool.

Yup. Suck that Iran, no bombs.

I don't think the solar thing will work, because it isn't always sunny. And the amount of pollution and GHGs produced creating the battery is the same as the amount produced by a conventional car in ~5 years.

Personal batteries, yes. Large scale operations do not use chemical batteries, instead other, more cost-efficient systems. For instance, pumping water up during the day and generating power hydroelectrically at night. Also, I understand that molten salt solar systems work by melting salt and using that to boil water. The heat is supposedly so intense it can operate for twelve hours without sunlight.

Molten Sodium and they last for 3 days without light ^_^

How would that work? The heat capacity of molten sodium is lower then 1.5 kj/kg*K, which, though not bad, is hardly impressive. For comparison, the proposed salt mixtures that would be used for molten salt heat storage are often quoted to have heat capacities similar to water, which would put them at roughly 4 kj/kg*K, making them twice as effective at storing energy as molten sodium.

[Mattasmack]

Hi all,

The molten salts that solar thermal power systems generally use are mixtures of sodium nitrate and potassium nitrate (for example: http://www.coastalchem.com/PDFs/HITECSALT/HITEC%20Heat%20Transfer%20Salt.pdf ).  Not pure sodium.  The stuff itself isn't terrifically chemically active, but its temperature alone is enough to ignite combustible materials when they come in contact.

...
But yes, solar thermal salt facilities are great, with only a few problems. 1: they are fragile, sandstorms, snowfall, hail strong wind, tornadoes, etc can damage them. 2: they only work well in deserts, so they will need a major upgrade to power distribution. 3: salt quickens rust for most metals, so we are not sure of what the maintenance costs are going to be in the long term yet.

Orbital solar power will most likely only an option if we build them from materials harvest outside the earth.

2: The problem of nobody living in the desert where the sun is, is indeed a problem.  But while it may mean that electricity generated by CSP (concentrating solar power) plants can't be used by everyone, it still can be useful for quite a lot of people.  For example, DESERTEC is looking at building HVDC transmission lines to bring solar power from northern Africa to Europe.  Granted, the events of the last several weeks might have put the kibosh on that.

1: The fact that the plants would be built mostly in the desert helps with a lot of weather-related problems: not many hailstorms, tornadoes, etc.!  The plants actually aren't that fragile.  The mirrors are generally made of 4 or 5 mm thick glass and don't break that often.  The mirrors in the SEGS plants in California have been holding up quite well for a couple decades now.  For parabolic trough power plants, breakage and leakage of the glass vacuum jackets around the receivers is a problem, but over time the companies involved have been learning how to reduce that.  And for a power tower design that component doesn't exist.

3: Several grades of stainless steel do just fine in contact with molten salt.  Exotic materials aren't required.

...
Molten Sodium and they last for 3 days without light ^_^

How would that work? The heat capacity of molten sodium is lower then 1.5 kj/kg*K, which, though not bad, is hardly impressive. For comparison, the proposed salt mixtures that would be used for molten salt heat storage are often quoted to have heat capacities similar to water, which would put them at roughly 4 kj/kg*K, making them twice as effective at storing energy as molten sodium.

I haven't seen any claims that the salt would have a higher heat capacity than water, and as long as we're comparing straight-up heat capacity (kJ/kg-K) I don't think it could be true.  But, often thermal storage systems are compared based on the volume or mass or price of the whole system, and that's not quite the same.  For example, two materials may have the same heat capacity, but if one can tolerate higher temperatures than the other, a system using that material could store the same amount of energy with less mass.

[Virex]

True of course, though I thought I saw a heat capacity value of 3.6 or 3.8 kj/kg*K somewhere. Of course the temperature also matters, but then I'm wondering why they're using the mix you refer to instead of, say, molten ceramics which have a significantly higher melting point.