See this article, and the links to the NREL for cost data (which Kurzweil does also talk about). Solar energy output per dollar has been improving with a doubling time of about a decade for several decades. If that trend continues, then it will be cheap relative to existing alternatives by the time Kurzweil projects gigantic market share. And prior to that there are markets in areas where competing electricity is expensive (theft on the lines in India, lack of connection to the grid in poor areas, the correlation of solar with peak load for air conditioning, places with carbon taxes) to absorb a lot of growth.
And cost improvements come not only from efficiency in absorbing flux, but from reduced use of materials, more efficient manufacturing processes, and so forth. Balance-of-system costs have also been going down. Distribution costs apply to other power sources (although distributed solar in some places benefits because homeowners can use the solar themselves, and free ride off the utilities for distribution, an implicit subsidy for early growth). Non-arable desert land is not particularly high value, nor are roofs.
Ray Kurzweil's writings are the best-known expression of Singularity memes, so I figured it's about time I read his 2005 best-seller The Singularity is Near.
Though earlier users of the term "technological Singularity" used it to refer to the arrival of machine superintelligence (an event beyond which our ability to predict the future breaks down), Kurzweil's Singularity is more vaguely defined:
Kurzweil says that people don't expect the Singularity because they don't realize that technological progress is largely exponential, not linear:
Kurzweil has many examples:
He emphasizes that people often fail to account for how progress in one field will feed on accelerating progress in another:
Kurzweil's second chapter aims to convince us that Moore's law of exponential growth in computing power is not an anomaly: the "law of accelerating returns" holds for a wide variety of technologies, evolutionary developments, and paradigm shifts. The chapter is full of logarithmic plots for bits of DRAM per dollar, microprocessor clock speed, processor performance in MIPS, growth in Genbank, hard drive bits per dollar, internet hosts, nanotech science citations, and more.
The chapter is a wake-up call to those not used to thinking about exponential change, but one gets the sense that Kurzweil has cherry-picked his examples. Plenty of technologies have violated his law of accelerating returns, and Kurzweil doesn't mention them.
This cherry-picking is one of the two persistent problems with The Singularity is Near. The second persistent problem is detailed storytelling. Kurzweil would make fewer false predictions if he made statements about the kinds of changes we can expect and then gave examples as illustrations, instead of giving detailed stories about the future as his actual predictions.
My third major issue with the book is not a "problem" so much as it is a decision about the scope of the book. Human factors (sociology, psychology, politics) are largely ignored in the book , but would have been illuminating to include if done well — and certainly, they are important for technological forecasting.
It's a big book with many specific claims, so there are hundreds of detailed criticisms I could make (e.g. about his handling of AI risks), but I prefer to keep this short. Kurzweil's vision of the future is more similar to what I expect is correct than most people's pictures of the future are, and he should be applauded for finding a way to bring transhumanist ideas to the mainstream culture.