Two of my favorite thinkers are Steven Den Beste and Thomas PM Barnett. They both regularly help stretch my mind and provide lots of provocative, useful thoughts that have wide implications. They are what I like to call horizontal thinkers. They roam across the intellectual landscape assembling new and useful structures without diving in depth to work out the details (which would be vertical thinking). Barnett is even more of a horizontal thinker than SDB but I believe that he better understands the limitations of this particular mode of thought and doesn't fall into the major trap of horizontal thinking, thinking that variables are constants and making generalizations that, on further, deeper examination, simply don't hold up.
SDB has a pretty good summary posted on his site of the process by which we would follow in ending the oil age to replace it with some other energy source. His article fails in that it has some factual errors in it which are sufficient to invalidate his conclusions on new energy sources. It's a particularly thorny problem of article analysis because on the larger point he's right, ending the oil age isn't going solve our terrorism problem (that analysis is going to be another post after this one).
My beef with the article is not that there is some easy way to end the oil age. But the problems are tough and challenging, not nontrivial.
From Den Beste's previous note on electric cars we find out that terrestrial solar is at most in the range of 240 watts per square meter. This contrasts with orbital solar which has a value of 1400 watts per square meter, 5.8 times the energy available per square meter. This is the foundation of the promise of extra-atmospheric solar energy (of both orbital and lunar varieties).
The first major problem in the realm of facts comes here:
Solar satellite power generation is particularly poor in this regard. Sunlight is concentrated using mirrors (with some losses) onto a boiler (with some of the light reflecting instead of being converted to heat, and some of the heat radiating away via black-box radiation). The next few steps are the same as for a coal plant: steam drives a turbine, which drives a dynamo, which generates electricity. At that point, all you have to do is to deliver it, but that is not easy with solar satellites.
No design for solar power generation that I have ever seen uses this system. They're all based on solar cells and most of those designs have fresnel lenses over those to concentrate solar energy onto the cells. Solar cell efficiencies is another (smaller) error that affects his reasoning. Typical commercial cells are not 10% efficient as his background article states but rather are currently at 15% and going up. As Den Beste points out himself, incremental changes in any long chain conversion can have large results in the end:
The efficiencies of every step have to be multiplied together to calculate the overall system efficiency. If you have five steps and each one wastes 20%, then each step has an efficiency of 0.8, and the overall system efficiency will be 0.8*0.8*0.8*0.8*0.8 == 0.328, meaning about 33% of the original energy would be delivered to end users, with the remaining 67% being lost. But if each of those five steps wasted 30% instead of 20%, the overall system would only deliver 17% of the original energy. The more conversions required, and the worse the efficiency on those conversions, then the lower the efficiency of the overall system.
Since some applications are profitable at 15% efficiency, solar cell efficiency improvement work is no longer pie in the sky but a commercial imperative that will generate continuous, small, incremental improvement in photovoltaic efficiencies as time goes on. This sort of virtuous circle where a small profitable market creates incentives to increase efficiency, thus enlarging the market are what you want to look for in determining whether a larger, challenging project is merely difficult and challenging or nontrivial.
SDB makes a claim that microwave conversion to electricity is a very lossy procedure. This is only if DC-RF conversion of 85-90% (pdf link) is considered "a lot of losses". I don't think that's 10%-15% in loss was what SDB had in mind when he said this.
SDB is more right regarding the RF-DC conversion inefficiency on the other end. That figure seems to be in the mid 20% range. There doesn't seem to be much of a virtuous circle there with no obvious currently profitable applications so this end is in need of basic R&D to make work.
Atmospheric effects (another potential loss) are generally pretty predictable and affect some wavelengths far less than others. It is certain that the wavelength picked for transmission will be one which minimizes distortion.
SDB didn't get into it much this time but lift costs are a huge barrier to orbital solar power stations. With the availability of new materials, space elevators and other novel lift platforms are becoming feasible and will radically lower lift costs.
But even SDB's preferred solution of core taps succumbs to his horizontal thinking vagueness. He's right that laser drilling looks promising but he doesn't seem to realize that laser drilling is recognized as faster and is being seriously scrutinized as the next generation drilling technology of choice for the oil and gas industry because it works faster than conventional drilling technology.
SDB took on an almost impossible task, proving that something cannot be done feasibly. Very great scientific minds are regularly embarrassed by previous negative predictions that something will not happen or cannot happen. Such pessimistic predictions are almost always wrong in the end. SDB hasn't improved the pessimists' batting average.
Update: SDB has kindly linked and swatted me on the backside for a factual misstatement of my own. My response:
I'll pick this up in the evening for a fuller response. I have to earn my bread on the road today.I'll concede that my knowledge of conversion % is pulled from Google searches. But the problem of relegating things to 'nontrivial' (ie not in our lifetime) status is a very hard thing to do and be right about it when we're talking about engineering problems that significant groups are seriously working on. I stand behind that larger point. I suggest that oil sands is a case in point. The current price to extract is ~$12/barrel. That has led Canada to jump to the #2 spot in worldwide oil reserves as of last year. If you think back to the Carter years, the naysayers were saying this would never happen (and I believed them at the time). It took a generation, but here we are. The major problems left are water availability (current process is water intensive) and environmental degradation (largely water related). I expect that things will improve over time.
This war is going to be a generational struggle. We need to start laying the groundwork so we don't run into an extremely damaging energy bind as we bring gap nations into the core over the next several decades. Working out each of the individual problems in as many new potential power sources as possible has to be part of that.
SDB says that he's not trying to say that these power projects are impossible, just too far down the road to be politically relevant for this war. I think he's underestimating how long this struggle is likely to last. Beating down the Islamists is only the beginning of the problem of super-empowered individuals in disconnected, messed up societies.
Posted by TMLutas at June 4, 2004 07:22 AM