Sometimes, the more you learn about a thing, the more information you gather and the more people you talk to about a specific topic, the harder it is judge. That’s definitely the case with aviation biofuels which are, in a sense, leading the charge towards a greener, bio-based fuel economy. I have pored over dozens of reports, research presentations, studies and news articles on this topic and conducted a number of interviews.The impression I get is of an industry operating on an underlying assumption that biofuels are an inevitability. The typical headline reports on some new development or milestone that’s been achieved, but down in the body of the story, you rarely see the offsetting qualifier noting that the entire edifice isn’t out of the R&D phase yet. There’s a strong tendency to green wash everything, including editorial coverage. When you ask, “how much,” people stop talking.There are aspects of this story that I find encouraging and some that I find worrisome. Specifically, the sheer amount of research work in this area is staggering. There are probably dozens of processes using just as many bio feedstocks and the fact that the Navy and Air Force are throwing money at the problem will have inevitable spinoffs for the commercial side. The fuels themselves-specifically hydrotreated renewable jet-seem to perform well, so well in fact that the Navy is satisfied that the principle part of its testing is done. It wants to run all of its airplanes and ships on a 50/50 blend of petroleum by 2020, an ambitious timeline.On the piston side, Swift fuel continues its research. Although Swift was initially pitched as a biofuel, I now believe that’s a misnomer. It can be a biofuel, if its acetone-based feedstock is derived from biomass. But in my view, the reality is more agnostic than that. Swift’s work has concentrated on the downstream side-how to turn acetone into high-octane binary fuel-not the upstream side, which is making the acetone from biomass in the first place. Right now, Swift’s largest challenge is finding cheap acetone, regardless of its source.What makes me skeptical of green hysteria is how news stories tend to ignore how or even if biofuels fit into the larger trends of energy development and history. The New York Times’ Thomas Friedman is a high-profile cheerleader for everything green, but I wonder if he’s ever applied a calculator to some of the claims advanced by the green fuels industry, specifically, the overarching consideration of energy density and, related to that, capital density. Density in this context isn’t BTUs per gallon-the alternative aviation fuels prove they perform well-but how much fuel you can produce from a given amount of land, a single well, a delivery system or dollars invested in infrastructure.In their engaging essay on the history of energy evolution, The Bottomless Well: The Twilight of Fuel, the Virtue of Waste and Why Will Never Run Out of Energy, authors Peter Huber and Mark Mills note that alternative energy sources-solar, wind and biomass-are pushing against powerful historical trends. Pound for pound, wood as a fuel contained more energy than the human muscle-based carbohydrate economy it displaced; coal contained twice again as much; oil raises the ante twice again and nuclear sources many times more. In this context, biofuels are less dense and may require more resources-money-to produce. Less energy density at a higher cost doesn’t sound like the roadmap to success for the reality is that each new evolution of energy generation has delivered multiples of output while requiring the same or less input–human effort, capital, land and so on. Electricity has never been cheaper than it is now and we’ve never used more of it. Gasoline prices have been flat or declining against inflation and it has never been cheaper to travel from point A to point B.It’s too soon to draw any conclusion on where biofuels fit. But just putting simple numbers together gives pause. One biofuel expert told me that a 65-million gallon a year capacity biofuel plant would require biomass equivalent of 15 football fields a day of some sort of energy crop. And it will take many dozens if not hundreds of such plants to make a meaningful dent in U.S. energy consumption. (The U.S. uses about 380 million gallons of motor fuel per day.) Ignoring the challenges of scaling up the processes that convert biomass to sugars and then sugars to fuel, of the effect of weather and drought on crop yields, of finding the appropriate land, when you think about just harvesting and transporting all that biomass, you naturally have to ask: Are you sure this can work? The answer continues to be: We’re not sure yet. Think about that when reading rosy stories about biofuels.In the U.S., we have elegantly demonstrated how not to do biofuels in the form of the ethanol industry. Ethanol is a lousy fuel, its production competes with food crops, customers don’t like it and will like it even less when the EPA shoves E15 down the motoring public’s filler nozzle. For aviation interests, ethanol has been a disaster because it eliminates the option of using premium fuel for aircraft engines. But the real obscenity is that the industry floats along on government subsidies and mandates. It’s as if a company had a crappy product but convinced the government to make you buy it and then got tax breaks after the sale. If the advanced biofuel industry is to succeed, we’ll need to avoid making that mistake again.So in order not to run afoul of Huber and Mills’ powerful historical trends, advanced biofuels will at least have to be equivalent in cost to petroleum based fuels and if they are to be the paradigm shift some people imagine, they’ll need to be cheaper. Good luck. Maybe the advent of peak oil will change the equation. Or maybe they’re not a paradigm shift at all, but merely part a liquid fuel mix that includes oil for the foreseeable future.Although I’m skeptical, I’m encouraged by the work going on in the biofuels industry. Most of it is good science and I see that as positive for its own sake. It’s bound to yield useful advances, even if replacing oil isn’t one of them.
For two related podcasts on this topic, see: