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.

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.