I have the enormous advantage as an energy writer that I have read Alvin Weinberg's writings on Energy, and have some idea of the extent of Weinberg's vision. In the world of the blind, a one eyed man is king. And as an energy writer, I am at best a one-eyed man. My education is not in science, and we clearly need a scientist to think the problems through that clearly go beyond my conceptual skills. Such a person is Barry Brook, who is rapidly emerging as a first rate energy thinker. Barry is a climatologist, and got into the energy field because he realized that it was not enough to talk about the climate problems, they had to be fixed. Barry has the intelligence, and the conceptual skills to move very rapidly once he reached that point, and he has reached the point where he is beginning to educate the rest of us, who a few months ago thought of ourselves as the most advanced energy thinkers in the world.
Barry has begun a series of Brave New Climate posts on energy fundamentals which should be required reading for anyone who wishes to claim expertise in energy issues, at least in the near future. They include
1. Thinking critically about sustainable energy (TCASE) 1: Prologue
2. TCASE 2: Energy primer
3. TCASE 3: The energy demand equation to 2050
Bottom line: 2050 power demand will be ~10 TWe of electrical generating power — a 5-fold increase on today’s levels, requiring the construction of ~680 MWe per day from 2010 to 2050. . . .4 TCASE 4: Energy system build rates and material inputs
So, now, let’s say that by 2050 we have managed to achieve the following:
a) Transition to an all-electric society with nuclear power meeting the greater fraction of our demand;
b) Use nuclear power and renewables to create our energy carriers (e.g. batteries, hydrogen, ammonia, boron, whatever), and also use waste heat from thermal reactors for desalination; and
c) Increased technological development means that we get 30% more efficient at using energy to do work (e.g. cumulative improvements in electrical appliances, but excluding transport, see below) — that’s an 8% improvement per decade (one imagines that in reality, the biggest efficiency gains will come in the next two decades, with diminishing returns thereafter).
Given the large uncertainties associated with this forecast, the actual value could easily be as high as 15 TWe, which would up the daily built-out rate to a little over 1 GWe per day. But let’s stick with 680 MWe rate for this post.That would requireL
1. Wind turbines. Wind power collects ~2 W/m2 (or 2 MWe per km2), and this figure is not really dependent on the turbine size. (If you have larger turbines, you need to space them further apart. If you build large turbines with tall towers, the increased hub height does access stronger winds, increasing the yield by ~30%). The 2008 US capacity factor for wind was 23.5%. For our unit, let’s choose a widely deployed turbine, the 2.5 MWe (peak), the GE 2.5xl (rotor diameter = 100 m, hub height = 75 – 100 m, cut-in windspeed of 3.5 m/s, peak at 12.5 m/s, cut-out at 25 m/s).
To get 680 MWe average power, 680/0.235 = 2900/2.5 = 1,160 GE 2.5xl turbines per day, worldwide, spread over 340 km2 of land area (a square 18.4 x 18.4 km). Based on Per Peterson’s figures, this will consume ~590,000 tonnes of concrete and 310,000 tonnes of steel per day. Every day, from 2010 to 2050.
2. Solar thermal. In good desert locations such as the Sahara or central Australia, concentrating solar power would access ~15 W/m2 (or 15 MWe per km2). In Spain, it is closer to 10 W/m2. These figure are derived after taking account of mirror/heliostat spacing required to avoid shading. It agrees with current experience with solar thermal. . . .Or
To get 680 MWe average power, 680/0.4 = 1700/100 = 17 Andasol-3 plants per day, worldwide, requiring (in an ideal desert location) 45 km2 of land (a square 6.7 x 6.7 km). Or, to put it another way, this means rolling out 520 m2 of mirrors/heliostats per second, every second, from 1 Jan 2010 to 31 Dec 2050.
It’s difficult to get decent material estimates for this — the best I could come up with are these figures from David Mills, which give 220 tonnes of steel, 27 tonnes of glass and 320 tonnes of concrete for a 5 MWe peak plant (these quoted figures were for a system without thermal storage, so we need to about double the above number to get the equivalent sized mirror field for Andasol-3 and ignore material components of the storage system). This would equate to 215,000 tonnes of concrete, 150,00 tonnes of steel, and 18,000 tonnes of glass per day — shipped out to a remote desert site, each and every day, from 2010 to 2050.
3. Nuclear fission. The AP1000 reactor, a Generation III+ design by Westinghouse that is now being heavily deployed in China, has a small concrete/steel footprint compared to other designs (see figure) — about 100,000 m3 of reinforced concrete incorporating 12,000 tonnes of steel rebar. The AP1000 unit’s island buildings would cover about 40 ha (0.4 km2) and generate 1,154 MWe (peak) at a capacity factor of 91.5% (based on US 2008 operations).Conclusion:
To get 680 MWe average power, 680/0.915 = 743/1154 = 0.64 (close to 2/3) AP1000 plants per day, worldwide, or roughly 2 x AP1000 reactors every 3 days, from 2010 to 2050. (This would require ~90,000 tonnes of concrete [based on 1.4 tonnes per cubic metre] and 7,700 tonnes of steel per day). Compare this to the figures for wind and solar thermal given above!
The main point of this post, TCASE 4, is to take a one step in quashing the absurd ‘bait-and-switch’ meme that some disingenuous anti-nuclear folk repeat: That because the energy replacement challenge facing nuclear energy is huge (a 25-fold expansion on today’s levels), it couldn’t possibly do it, so renewables are our only sensible option. On the basis of this post alone, any objective reader can see that this is pure, quantitatively unsupportable, nonsense. It’s going to be really tough, no matter what — and believe me, I’ve not even warmed up on the problems with renewables taking the lion’s share of the work.