Um. No. First, the term isn't defined or clarified, so you're simply applying an interpretation convenient to you. On page 3 you'll find growth assumptions clearly stated:
[T]he study explicitly assessed the challenges of a scenario in which nuclear power capacity expands from approximately 100 GWe in the United States in 2000 to 300 GWe at mid-century (from 340 to 1000 GWe globally), thereby enabling an increase in nuclear power's approximately 20% share of U.S. electricity generation to about 30% (from 16% to 20% globally).
That is the growth which can occur unimpeded for up to 50 years.
You've also conveniently failed acknowledge the first half of that sentence, given in full here with the pargraph it occurs in:
Table 2 shows Red Book identified resources, undiscovered resources, and the number of reactor years of fuel provided by those resources. Based on the total projected Red Book resources recoverable at a cost less than $130/kg (2006$) of about 13 million metric tons (hence about an 80 year supply for 800 reactors), most commentators conclude that a half century of unimpeded growth is possible, especially since resources costing several hundred dollars per kilogram (not estimated in the Red Book) would also be economically usable.
We're still left with 80 years supply for 800 1 GWe reactors. Better than the near-term critical situation for liquid fuels, but hardly copiously abundant.
On Algae:
All of which are issues that are going to be solved
Yeah. So, Boeing's just released "the biggest breakthrough that there is out there" in biofuels, those are its director of sustainable aviation fuels, Darrin Morgan's words, not mine. Halophyte (pickleweed) farming integrated with aquaculture for aviation fuel production at ~75 gallons/acre-year. Aviation fuel is around 5% of total US oil consumption (15,998 million gallons in 2013, RITA), roughly 1 million of the 20 million barrels of oil consumed daily in the US.
Supplying just 5% of US oil consumption from pickleweed would require 21.3 million acres under cultivation. That's about 330,000 mile^2, or a region 577 miles on a side. You could start in Shreveport, LA, and drive all the way around Oklahoma and Kansas without ever entering them. Boeing's article mentions having "thousands and thousands of hectares* under cultivation. How about millions and millions?
http://www.reddit.com/r/dredmorbius/comments/1wo2hl/boeings_...
Algae are, typically, about 10x more productive than plants, but present their own host of challenges (infrastructure and capital requirements, disease, water, fertilizer, waste removal, plumbing issues). Since the above calculations are for a 5% replacement of petroleum, you could take the same acreage and say instead you're getting 50% of present oil usage. Realize that those 21.3 million acres _now all have to be constructed_ with pumps, drainage, etc. And somehow supplied with water. And placed somewhere that they don't interfere with existing food, habitation, and essential ecosystems.
Good luck with that.
Human ingenuity
Can you demonstrate a single case in which human ingenuity has created a new entropic gradient to exploit, rather than found an existing one? What existing gradients can you point to that we can tap? We've covered nuclear and biofuels here. I see solar, wind, geothermal, hydro, and tide/wave left.
I'm not sure those two quotes are talking about the same thing. I notice that different numbers are quoted in different statements in the document; for example, on p. 12 there is this statement:
This reinforces the observation in the 2003 MIT study that “We believe that the world-wide supply of uranium ore is sufficient to fuel the deployment of 1000 reactors over the next half century.”
Which is different from the "80 years for 800 reactors" statement.
But more importantly, you're ignoring additional information that's given in the same sentence we've been quoting and the one immediately following it. You expanded the quote to give the first half of the sentence, but you conveniently ignored the last part of the sentence, which I'll repeat: especially since resources costing several hundred dollars per kilogram (not estimated in the Red Book) would also be economically usable. I.e., the "80 years for 800 reactors" figure (and by implication the "1000 reactors over the next half century" figure) does not include all estimated resources. The very next sentence is:
Using a probabilistic resources versus cost model to extend Red Book data, we estimate an order of magnitude larger resources at a tolerable doubling of prices.
I.e., at twice the current uranium price (which, as I noted before, would mean only a small increase in the price of nuclear electricity to the end user, unlike fossil fuels where fuel cost is a major factor in end user price), we have 10 times as much available, meaning 80 years for 8000 reactors, or 10,000 reactors over the next half century. That's a big difference. And since uranium prices will certainly go up if it becomes scarcer, there will be natural economic forces driving people to tap the 10 times as much uranium that's available at higher prices. So you are conveniently failing to acknowledge information that's in the document you linked to. (And that's still leaving out breeders, which as I noted before, were left out of the MIT study for economic reasons, not technical reasons, and as uranium prices go up the economics change.)
those 21.3 million acres
Or about 23 percent of the area currently under cultivation in the U.S. (922 million acres according to Wikipedia). But we're talking about 25 to 50 years, not right now. There's no reason why algae acres have to displace current farm acres on that time scale. That 21.3 million acres is about 9 percent of the land area of the U.S, which is significant but doable. Or, if we wanted to get creative, we could put the algae farms on platforms offshore and out of the way (and with easy access to fresh water using desalinization rigs--or even using salt-water tolerant algae).
Good luck with that.
In the next 25 to 50 years, the items you list are easily doable. That's not to say they'll actually be done; but once again, the main obstacles I see are political, not technical. I notice you haven't commented on that at all.
Can you demonstrate a single case in which human ingenuity has created a new entropic gradient to exploit, rather than found an existing one?
Of course not; that would violate the second law of thermodynamics.
What existing gradients can you point to that we can tap?
Here on Earth, for the near future, you've covered all the significant ones I'm aware of (assuming solar includes solar thermal as well as photovoltaic; I haven't seen a lot lately on solar thermal, but it seems like an obvious alternative worth pursuing).
P. 12 of that study says "most commentators conclude that a half century of unimpeded growth is possible", and the study appears to agree with that assessment. "Unimpeded growth" means a large increase in consumption rate over the present.
Also, that assessment is based on a once-through fuel cycle and mining as the only uranium source. Over a half century to a century time scale the first assumption is almost certainly invalid (breeder technology is advancing) and the second may be shaky as well. (Note, btw, that a key reason why the MIT study assumed a once-through fuel cycle was not that breeders were not available, but that they were uneconomic at current uranium prices; but obviously if uranium gets scarcer, uranium prices go up and breeders become economically viable.)
Finally, a half century is not 25 years. If we have a half century to a century of nuclear power even with a once-through fuel cycle, we have an obvious alternative to fossil fuels for that time frame. Your claim that we will hit an energy crisis in 25 years assumes that there is no such alternative.
Tell me how much algae fuel you want and what conversion pathways (biodiesel, ethanol, synthesis, solids) you're referring to. Then give me acreages and water estimates. Oh, and how you're going to fertilize all that goop and keep pests out of it.
All of which are issues that are going to be solved, if they're not solved already, probably well within your 25 years, certainly within a half century. Google turns up plenty of hits on "algae fuel" or "algae fuel study" that show plenty of progress in this area.
the foundation for your optimism
Human ingenuity plus profit motive plus an obvious market for cleaner forms of energy. What I noted above with regard to the assessment of breeders being viable is true more generally: a key limitation of most assessments of available energy resources is that they only look at what's economical given current prices, not what's possible. But the economics will change.
That's not to say that there are no obstacles; but as I said before, the main obstacles I see are political, not technical.