The RDA can't do physics

[Human No More]

Originally Posted by Clarke

Acording to this page, the world energy consumption in 2003 was 20,261TWh, and so the power of that year was 20261e12/1 year = 2.313 TW. The ratio between these is 50.3. IOW, the RDA require the power of 50 modern Earths to fuel an ISV. I presume that JC does not mean to imply that the RDA rule (a large chunk of) the world of 2154?

Now, I'm disinclined to believe that the RDA actually have access to this, because the expanded canon tells us that Earth's current major power source is fusion reactions.

Actually, it only says that fusion provides for a majority of Earth's power. It does not describe the source of the antimatter for the ISVs.
Trust me, you can't argue canon with me

These are nowhere near powerful enough to provide the requsite power, as I'll now demonstrate. ATM, there are 441 fission reactors in the world, providing 379GW of power. This gives a rough ratio of 859 MW per reactor. Fusion as a process is roughly 5 times as efficient (per mass of reactant) as nuclear fission is. Let's give the future the benefit of the doubt and say each reactor is 10 times as efficient as fission ones, so each produces 859*10 MW = 8590MW each. So, a simple division tells us that the RDA requires 116,000,000/8590 = 13,505 reactors. (Ignoring the fact that modern reactors take thousands of staff as well...)

Not only does fusion require lower staffing levels due to its safety, but it's far more scalable. The majority of fission reactors today are ancient and should have been decommissioned 10-20 years ago.
A fusion reactor explicitly allows a higher capacity without the danger of producing a critical mass when not operating. The only known upper limit would be the largest known star - clearly, that is impractical on Earth, but it does not suffer the same limitation as fission.

I hope you can understand why I don't like this idea. Although a Dyson solar collector would stop it being such an impracticality, this isn't mentioned in the background material AFAIK, and so, IMO, assuming it's there is handwaving. (which is, apparently, unrealistic. )

There's no mention, but there's no denial of one. All there is is a mention of how poer is produced on Earth, which is said to produce more energy than people can use.

Construct Hell's Gate either automatically or by remote control from the Venture Star.

Remember that robots will weigh just as much.

From there, construct most of your equipement on-site

Already done.

If the microchips controlling the robots cannot be manufactured to any degree, then load a large amount of them onto the Venture Star. (i.e. 5000 or so)

Already done.

The Avatar program is essentially a sunk cost; whether it goes ahead depends on how valuable the RDA consider PR to be, and it produces no profit.

1. Wrong. you seem to believe unobtainium is the only profit source just because sefridge said that, but that doesn't make it true. there is a lot of genetic research, for example in using plants that absorb metals form the soil in cleaning up contaminated areas on Earth.
2. If you actually watched the film, you'd know that that is entirely the point, because being seen not to be harming the Na'vi does help their image, even if many people do realise what's really going on. Using robots everywhere would totally destroy that perception and then some.

The defense should be done with energy weapons, most likely electrolasers and masers. This is because the primary running cost of any weapon is the ammunition, which in the case of energy weapons is nearly free, and requires no specialised machinary or specific resources.

Wrong.
Lasers do not exist in a useful form (weapons on Earth are gauss-type). The RDA can not use those because they do not require advanced military hardware. This is not an invasion, and they are not supposed to be causing any damage.
They're being limited by governments and organisations like the UN here, in that a species of sentient beings deserve equal rights, even if unobtainium is useful. That means the RDA are not going to have advanced military hardware for some kind of invasion like you wanted to see (in which case, there is plenty of fiction for you, don't try and use false logic to rationalise Avatar into something you wanted with spess mehrens killing everything).

Additionally, some types of energy weapon are capable of bypassing the natural armour of Pandora's fauna. Physical armour has no bearing on the effectiveness of a maser, and only very little impact on the effectiveness of an electrolaser.

Again, there's no need to do so, because they aren't going for mass slaughter. What they have is enough for their actual needs that they are supposed to be using it for.

The energy you need to power all of this is provided by fusing water, which can presumably be found in abundance. (There is mention of the Eastern Sea.)

Actually, it uses He-3 from Polyphemus.

The materials are provided by mining, as well as recycling everything you can get your hands on. Solar panelling on the Venture Star may also be used to begin with, but fusion will be more reliable and efficient. Since Hell's Gate will be smaller than even an Earth town, power becomes functionally unlimited, so long as instaneous energy output is not too high. This will be more than enough to support the humans living there.

The presence of energy for hell's gate doesn't mean they will have ridiculous military lazor weapons that aren't even mentioned on Earth.

Oh, just as a closing note, look at my numbers in the first paragraph or so carefully. I worked on the basis of the ISV weighing 5 tons. The actual Project Valkyrie specification that the Venture Star is based on gives a mass of roughly 100 tons. The numbers above are a gross underestimation and yet IMO, they are still impossibly large.

Again, nobody has ever stated where the actual energy for the ISV comes from.