So far, no response to my challenge, and in particular, nobody has posted a failure of the Woodward Hoffmann rules. Why not? One answer would be, there are none, so there is nothing to post. Then there is the possibility that there are examples, but nobody can find them. More depressingly, nobody cares, and finally, most depressingly of all, at least for me, perhaps nobody is reading my blogs.
 
Meanwhile, I have had a topic request! What about transport fuels? Conceptually, a plan is the same as a theory, and in this case there are plenty of theories as to what we should do, so the question now is, how do we choose which to follow? To slightly amend a quote from General Wesley Clark, there are two types of plans: those that won't work, and those that might. We have to select from those that might work and make them work. Accordingly, the art of selection involves the logical analysis of the various plans/theories. I must start with a caveat: I have been working in this area during both the previous oil crisis and now, and while I have considerable experience, it is in one area. The reader must accept that I may show bias in favour of my own conclusions.
 
My first bias regards methodology. A particular source of irritation is the request, when proposing a process, for an energy balance. In one sense, from time symmetry, I know energy is conserved so the energy is always balanced. If they mean, how much do you get out usefully, the answer is, the second law says, less than you put in. However, even if you account for this (usually, with varying degrees of optimism!) this is of no use in selecting a process. When you enter certain intellectual areas, there are rules to follow. Just as in chemistry it is totally pointless to try to derive a theory while ignoring atoms, in economics the only relevant means of comparing processes is based on money, because this alone is intended to balance all the different factors. It may not be perfect, e.g. environmentalists will tell you that no proper cost is placed on environmental protection, but it is all we have. To illustrate why, suppose you wanted to go somewhere and someone offered you a megajoule; would you prefer a container of gasoline, or a mass of water at 35 degrees Centigrade?
 
When forming a theory to address a commercial issue, the first question is, what is the size of the market? According to Wikipedia, world oil production is 87.5 million barrels a day (13.9 billion litres per day). To put that into perspective, I once saw a proposal to build a small demonstration plant that would convert 35 t/day of cellulosic material into biofuel. If successful, it might have produced up to 11,000 litres per day. Yes, it is a small plant (designed for a specific source of raw material) and you can imagine increasing its size, but whatever factor you multiply by, this is going to have to be repeated an enormous number of times. It is most unlikely that anybody can come up with a single raw material to supply this volume. This brings a first conclusion: there is no magic bullet. If we are to solve this problem, contributions will have to come from a number of different sources. Accordingly, we are not looking for a unique plan.
 
An immediate second conclusion is, there is no overnight solution. We have built up a system over one and a half centuries based on the assumption that oil will be cheap and widely available and that has led to some fixed infrastructure that cannot be replaced overnight. Fuels have evolved from a simple distillation to high performance fuel such as JP-10, which appears to have as a major component tetrahydrodicylopentadiene. The very large modern oil refineries are extremely complicated systems that use experience learned over that period. Different processes have to start smaller. Furthermore, it will take at least a decade, and probably longer, to even get a new process to a successful demonstration plant.
 
So, what processes might work? It may come as no surprise to hear that several quite promising processes were developed, at least partially, during the previous oil crisis, then abandoned once the price of oil fell. Over the next few weeks, interspersed with the other subjects, I shall give my views on what should be done. In the meantime, as a possible further challenge, how many of those earlier proposed processes are you aware of? My guess is, most of the information gained then is lost, other than possibly residing in the heads of retired scientists and engineers. This raises another very important point in terms of economic theory: there is an enormous amount of work to be done to solve this fuel problem, the economic system appears to be creaking under government debts incurred in times of unparalleled prosperity, so can we afford to waste what in principle we already have?