It's a "hard-headed" engineering look at our energy options written by a physicist. It might be a bit outdated (published in 2008), but when it came out it was the best compendium I'd seen.
Note that some of the statements there (e.g. estimates of areas needed to provide power from solar energy) are not technology-dependent (ie. are about physical limitations).
"If a breakthrough of solar technology occurs and the cost of photovoltaics came down enough that we could deploy panels all over the countryside, what is the maximum conceivable production? Well, if we covered 5% of the UK with 10%-efficient panels, we’d have 10% × 100 W/m^2 × 200 m^2 per person ≈ 50 kWh/day/person.
I assumed only 10%-efficient panels, by the way, because I imagine that solar panels would be mass-produced on such a scale only if they were very cheap, and it’s the lower efficiency panels that will get cheap first."
This assumption was invalidated by the actual trajectory of solar power since 2008. Nobody is building solar farms with 10% efficiency panels any more. Low efficiency is too expensive -- because it requires more glass and aluminum for the panels, more cabling, racking, and labor for installation. Low cost, low efficiency Chinese panels, like the GCL Poly ones used at India's giant new solar farm that HN just had an article about, are now in the mid-teens. (I looked up the data sheet after getting a glimpse of the GCL shipping crates on that Indian project site):
If they used the middle-of-the-road GCL‐P6‐60‐240 that's a 14.7% module; 47% better than MacKay estimated as the best one could hope for from large scale solar projects. And the minimum competitive efficiency for even low-price panels is still creeping up. (Though large scale storage sufficiently affordable to get UK energy primarily from PV is still but a dream.)
MacKay also made the challenge look even bigger than it is by estimating the energy consumption of a "typical moderately-affluent person" and then multiplying that value by the whole population of the UK:
http://www.inference.phy.cam.ac.uk/withouthotair/c2/page_22....
This leads to large over-estimates relative to actual measured UK energy consumption, particularly from air travel and automobile travel.
Fair point. He says that the 20% estimate is unlikely to be revised upward, but it's "unlikely because you can't get more than 30% using reasonable approaches to PV" and not "unlikely because you can't get more than 30% due to thermodynamics" (I can't find what's _that_ limit quickly).
> MacKay also made the challenge look even bigger than it is by estimating the energy consumption of a "typical moderately-affluent person" and then multiplying that value by the whole population of the UK (...)
Here I'd agree with him: we need to find energy sources that will deal with projected future demands.
Projected future demands for energy per capita in the UK and other developed countries grow very slowly, or even decline. Primary energy consumption per capita in the UK has actually declined since 2008 when MacKay wrote his book (you'll need to select countries yourself to see the data):
You might think that's just because the UK doesn't do manufacturing any more, but look at manufacturing powerhouses Japan and Germany: they also have seen per-capita declines since 2008.
Ecologists and economists alike seem to have a default assumption that human resource consumption is insatiable; they just have different attitudes about that assumption. I don't know how many years of trends like the one I just linked it will take before they reassess resource satiety.
Although I'm assuming this particular combination doesn't provide favourable enough economics (or it would probably be a household name already), I can definitely see how this approach in general could. You could have the best of both worlds: cheap, but slow charge/discharge storage combined with the ability to very quickly scale up to meet peak daily demand for a limited (but sufficient) period of time.
https://en.wikipedia.org/wiki/Grid_energy_storage
I think it's an interesting field though.