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1 Sep, 2009 12:19 pm
Broadly speaking, in the world of next generation biofuels there are contenders, pretenders, and niches. Over the past decade, we have thrown a lot of money at pretenders and have little to show for it. Fundamentally I believe it boils down to the fact that our political leaders can't sort the wheat from the chaff. They listen - often to the very people who will benefit from more funding - and then they allocate money. Billions of dollars and little progress later, they or their successors may begin to realize that they have been misled and they start to dial the funding back.
Here are some examples:
The poster child for the pretenders. Proponents ignored practical realities in many different areas, including fuel cell vehicles that cost a million dollars, the fact that most hydrogen is produced from natural gas, the fact that the energy density of hydrogen is very low, and the fact that there are multiple issues with hydrogen storage and transport. Technical breakthroughs were being counted on to solve these challenges. After all, we put a man on the moon. Surely we could solve these challenges.
The real problem is that the potential for success falls rapidly as the number of needed breakthroughs pile up. Imagine for instance that the following - cost of production, cost effective storage, and cost effective transport - each have a 25% chance of achieving commercial viability in the next 20 years. The total chance for success of all three in that case falls to 1.5% - so this is overall probability of success. Thus, the vast majority of technologies that require multiple technical breakthroughs will fail to materialize commercially except perhaps over a much longer period of time.
As was the case with hydrogen, this one requires multiple technical breakthroughs before commercial (unsubsidized) viability can be achieved. The fundamental reason that cellulosic ethanol won't scale up to displace large amounts of gasoline is that the energy efficiency of the process is so low. You have the sugars that make up cellulose locked up tightly in the biomass - which has a low energy density to start with. So you add energy to unlock the sugar and turn it into ethanol, and then you end up with ethanol in water. More energy inputs are required to get the ethanol out. Even if the energy can be supplied by the by-products of the process like lignin, the net BTUs of liquid fuel that you end up with are going to be low relative to what you started with.
For example, assume you start off with 10 BTUs of biomass. You expend energy to get it to the factory, to process it, and then to get the water out. You burn part of the biomass to fuel the process, and input some fossil fuel. You might net something like 3 BTUs of liquid fuel from the 10 BTUs of biomass you started with.
Don't confuse this with fossil fuel energy balance, though. If the external energy inputs in this example only amounted to 1 BTU of fossil fuel, one could claim a fossil fuel energy balance of 3/1. But that doesn't change the fact the final liquid fuel input is a small fraction of the starting BTUs in the biomass.
This is analogous to the situation with oil shale, which is why I have compared the two. There may in fact be a trillion or more barrels of oil shale locked up in Colorado, Utah, and Wyoming. But if the extraction of those barrels required a trillion barrels worth of energy inputs and lots of water - then that oil shale might as well be on the moon. That means that a trillion barrels isn't really a trillion barrels in the case of oil shale, and a billion tons of biomass is much smaller than it seems when talking about cellulosic ethanol.
So despite the claims from the EPA that the "Renewable Fuel Standard program will increase the volume of renewable fuel required to be blended into gasoline from 9 billion gallons in 2008 to 36 billion gallons by 2022" - that is not going to happen unless the government is willing to throw massive amounts of money at an inefficient process.
Like many, I was initially enchanted by the possibility of weaning the world away from fossil fuels by using fuel made from algae. Proponents wrote articles suggesting that we could do just that, provided the necessary investments are made.
Sadly, the story is much more complex than that. The U.S. DOE funded a study for many years into the potential of algae to produce fuel. (For an overview of where things stand from John Benemann, one of the men who co-authored the close-out report of that study, see Algal Biodiesel: Fact or Fiction?) The problem is again one of needing to surmount multiple technical hurdles, and the close-out report states that reality. Again, I won't go into those details, as that has been covered before.
While it is a fact that you can produce fuel from algae, the challenges are such that John has written that you can't even buy algal biofuel for $100/gallon. He said that if you want to separate the reality from the hype, just try to secure a contract with someone to supply you with algal fuel.
First Generation Biodiesel
This story is primarily about 2nd generation fuels, and as such I won't get into corn ethanol issues. But I will say a bit about biodiesel. As indicated in the Wall Street Journal story, conventional biodiesel producers are in trouble. Briefly, a conventional biodiesel producer is someone who takes vegetable oils or animal fats and uses methanol (almost all of which is fossil-fuel derived) and converts that into an oxygenated compound (called a mono-alkyl ester). This compound has been defined as 'biodiesel', and can be used - subject to certain limitations - in a diesel engine.
Again, the problems are fundamental. It takes a lot of effort (energy, cost) to produce most of the oils that are used as raw materials, and then you have to react with methanol - which usually contains a lot of embodied fossil fuel energy. Up til now, the first generation biodiesel producers have benefited from a high level of protectionism (to the extent of punishing the more efficient 2nd generation producers). But even with the protectionism and the subsidies, producers are still struggling to survive.
There are a number of miscellaneous pretenders that we probably don't need to discuss in depth, such as various free energy schemes or water as a fuel. If you think you might be dealing with a pretender, one caution flag is when their promoters are from backgrounds that have nothing to do with energy. For instance, the person who founded the dot.com that ultimately morphs into an energy company is almost certainly a pretender who is chasing investment funds.
To summarize, the biofuel pretenders fall into several broad categories. The big ones are:
• Most would-be cellulosic ethanol producers
• Most would-be algal biofuel producers
• Most first generation biodiesel producers
This isn't to say that none of these will work in any circumstances. I will get into that when I talk about niches. But I will say that I am confident that none of these are scalable solutions to our fossil fuel dependence. The problem is that political leaders have been, or are still convinced that there is great potential for some of these and we waste billions of dollars chasing fantasies. This is a great distraction, causing a loss of precious time and public goodwill as taxpayer money is squandered chasing schemes that ultimately will not pan out.
Originally published on R-Squared Energy Blog
Robert Rapier's career has been devoted to energy issues. He has worked on cellulosic ethanol, butanol production, oil refining, natural gas production, and gas-to-liquids (GTL). His previous job was as the Engineering Director for Accsys Technologies, but he is presently in Hawaii helping to build a bioenergy company.
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The issue of First Second and Third Generation Biofuels is always brought up when comparing that which was done before now and that which is currently under investigation and construction to the future. If as I hear that in the Netherlands a project to manufacture Ethanol from Municipal Solid Waste and miscellaneous other sources of Waste Biomass is in the throes of being built, and then being repeated in West Yorkshire Uk and also in the USA should you not take note.
It is agreed that Lignocellulose (a broad term for the mixture of Cellulose/Hem-Cellulose/Lignin/Ash we call plant matter has issues surrounding it with regards to the separation of the principal components and the need to refine the end products but that applies to all biomass. It is agreed that there are impediments to the processing of Ligno-Cellulose no matter what procedure you use but then even in the Combined Gasification Fermentation system proposed by B R I the process is not that secure. For example just a quick mass balance of the LignoCellulose raw material where we know the Carbon fgractionwill tell you that the 150 gallons per tonne is farcical. Look at it and you will see that if you are producing that amount of electricity something is drastically over-inflated and questionnable.
However, due to the nature of the long, drawn-out targets that most nations are setting themselves (setting targets for carbon reduction over the next decade and even to 2050, which technically don't have to be met until the year of that target) the solutions needed to reduce carbon emissions can be allowed to evolve over those time-frames (much to the dismay of environmentalists). To dismiss the effectiveness of future technologies based on current scenarios in order to justify a lower quality solution would be foolish in the extreme.
With further advances, hydrogen and algae have the potential to generate far higher fuel quantities per unit land and for far less resources, making them in the long term cheaper and more productive. Dividing land use between fuel and food will become one of the key contentious issues of the 21st century, and both will need to be done as efficiently as possible.