Ethanol – the champagne of fuels?
Drop-in fuels all the rage? Not smart, says Coskata CSO Rathin Datta, ethanol is the champion for biomass-based fuels.
In Washington DC later this month, at the DOE’s Biomass 2011 annual conclave, Rick Wilson, the CEO of Cobalt Technologies, and Wes Bolsen, CMO of Coskata, will engage in a formal debate over the motion: “Federal funding for biofuels should focus primarily on the development of infrastructure-compatible, hydrocarbon fuels.”
There has been quite a lot of press in recent years around the development of “drop-in fuels” – from articles like 2009’s “Drop In, Tune Out, Turn On” to the coverage of recent DOE funding of consortia like the NABC that are pursuing infrastructure-compatible fuels.
But Coskata has been on the warpath of late to remind the industry, and the broader stakeholders in a future beyond fossil fuels, about why ethanol fuels were developed in the first place, and why they should be considered a superior alternative to drop-in hydrocarbons, when refining fuels from biomass.
At the end of last month, Coskata CSO Rathin Datta didn’t exactly descend into the lion’s den, when choosing to present this strongly positive view on ethanol at the Fuel Ethanol Workshop in Indianapolis. It’s sort of like praising Cal Ripken Jr. in the friendly confines of Camden Yards.
But if the venue was unsurprising, the message was unexpectedly strong. Rather than describing ethanol as one of a group of preferred fuels – Datta took the view – along with a group of co-presenters from General Motors and Auburn University – that ethanol should be considered “the primary renewable liquid fuel”. Though too polite to say it, he leaves us to draw the obvious conclusion that all the companies making renewable gasoline can go home now.
You can download the Coskata presentation, here.
So, which is better – ethanol, or drop-in fuels?
Here’s the main thrust of the Coskata view: “For liquid fuel or chemical production from lignocellulosic biomass, the winning strategy is to produce a product that has proven and widespread use, with the highest yield – that is ethanol.”
Let’s examine that. Their analysis shows that around 40 percent of the weight of lignocellulose – whether it is woods, stover, energy canes or grasses – is in the oxygen. Here’s their chart:
Knocking those feedstocks down to hydrocarbons, inevitably lowers the yields in terms of available energy for combustion.
How much? According to the Coskata presentation, ethanol refining will produce theoretical yields in the 51 percent range, with 46 to 50 percent typically achieved in an industrial process. They contend that biobutanol yields are theoretically in the 41 percent range with “typical yields achieved” in the 23-25 percent range.
(Hmmm, we suspect that Gevo, Cobalt and Butamax are doing better than this. Wasn’t Gevo’s Luverne plant knocked down from 50 million gallons of ethanol to 38 million gallons of biobutanol? That’s in the 76 percent range. Tut-tut. But we’ll let it pass for now. )
Over on the hydrocarbon side, their contention is that theoretical yields from biomass are in the 30 percent range, with not much data to date on the yields achieved in industrial practice because the fuels are not yet produced at scale.
What does that mean?
According to this analysis, if you can get, say, 100 gallons per acre of ethanol, you would be looking at around 40 gallons per acre of hydrocarbon fuels, or around 50 gallons of biobutanol.
(Ha-h’m. See our slightly less vocal Hmmm, above.)
Now, biobutanol and hydrocarbon fuels contain more energy than ethanol on a per gallon basis – but, in the end, according to Coskata – you net more BTUs per acre with ethanol, and that should be the criteria for selecting a primary liquid fuel for transportation in a post-fossils era. Quod erat demonstrandum.
They contend:
1. Renewable biomass feedstocks that are efficiently and easily available are highly oxygenated
2. Ethanol is the primary renewable liquid transportation fuel with a long history of very good performance
3. Ethanol can be produced with high yields and efficiency with some conversion technologies – particularly the “Hybrid” of gasification with bioconversion – that have developed to the commercial implementation stage
4. Longer chain alcohols, lipids or hydrocarbons cannot be derived from renewable carbon sources with equivalent yields
5. Large quantities of renewable and sustainable biomass feedstocks to produce ethanol are available in the US and many other parts of the world.
It’s a powerful argument. (But beware of the possibility that this is a straw-man argument – or should that be stover-man?)
So, why drop-in fuels, anyway?
For now, let’s turn to the reasons the nation is looking at drop-in fuels, and see how ethanol stacks up.
Ethanol can’t use existing infrastructure – no one wants to build, or can afford, all those blender pumps, flex-fuel cars and pipe-lines.
Well, this is the driving reason to use a drop-in hydrocarbon fuel, isn’t it? Why rebuild the infrastructure? Blender pumps are expensive – maybe $30,000 a pop – and with all the flex-fuel manufacturing in the US, there are still around 8 million flex fuel cars out of a total US fleet of 300 million – which makes it difficult for a retailer to justify putting in a blender pump anyway.
Coskata responds with an interesting point. Pumps don’t last forever – they need to be replaced anyway, just around once every 10 years – why not simply replace a standard pump with a blender pump? That way, the conversion cost is absorbed into the normal capital replacement schedule. By 2022, you have blender pumps in broad distribution.
Should US manufacturers continue their commitment to, say, 50 percent or more of their fleet being flex-fuel enabled – by 2022, using a 17-year replacement cycle for the US fleet, perhaps as much as 33 percent of the fleet could be flex-fuel enabled, without changing the game on manufacturers.
Ethanol has hit a blend wall at E10 – E15 is a tough sell, and E85 is a bust – how is the fuel ever going to get used? Plus, E85 costs more per mile than hydrocarbon fuels.
E85 really hasn’t done all that well – a handful of pumps, nationally, less than 1 percent of fueling stations carry them, and the per-pump gallonage has been as dismal as could be expected with so few flex-fuel cars available.
One of the reasons that E85 has acquired a bad reputation is the mileage. A good part of that stems from the fact that engines are designed around E0 – that’s the reference fuel used to calculate mileage on the window sticker (that’s right, the EPA bases mileage on a fuel you can’t buy).
Now, engines can be programmed to sense 85 percent ethanol, and can be programmed to “handle” the fuel. But the real advantage of ethanol is in its high octane – 105 vs around 82 for straight gasoline – and the payoff there is that engines can run higher compression, when run on ethanol.
Higher compression, higher engine efficiency – in fact, a Ricardo engine running E100 gets almost the same mileage from ethanol as you get from gasoline – no 25 percent drop-off – that’s the value of compression.
The problem here? Flex-fuel cars do not mean flexible compression. That’s fixed – and fixed for E0.
Coskata’s idea? Make E30 the reference fuel for mileage comparison purposes, and design engine compressions that are optimized for E30. E10 will run fine, E15 too. Meanwhile, you start to pick up some of that engine efficiency from better compression, and that means almost no loss of mileage at E30.
That gives you a blender pump choice between, say, E10, E15 or E30. At E30, says Coskata, you’ll get the best deal, and that opens up a market of around 40 billion gallons of ethanol in the US, at the end of that 10-year gas pump replacement cycle.
Will all of that happen? Good question. But certainly an interesting argument worth thinking through.
Diesel fuels are the way to go for trucks and heavy equipment.
Well, that’s a good market for drop-in hydrocarbon fuels, although biodiesel producers may well make the same arguments about the yields and costs for biodiesel, vs drop-ins, that ethanol is making on the gasoline replacement side.
What about the military, or aviation? They don’t want to use ethanol – only drop-in fuels. Doesn’t the customer rule?
In aviation, the fuel density and cold performance of ethanol makes it a non-starter. Although it’s worth noting that the military has an alcohol-to-jet fuel program underway, and there may be an argument, when all the data is in, that a highly efficient way to produce jet fuel is to start by producing an alcohol fuel. It’s early days.
As for the military, they are a diesel market and jet fuel, generally speaking – so, for sure, their options will focus on those sources – and the drop-in fuels certainly solves infrastructure issues for capital-starved airlines and the debt-pressed governments.
Ethanol gets less mileage – isn’t range important?
Sure, range is important.
Of course, some of the people who are bagging on ethanol because you get around 250 miles to the tank on E85, will tell you that plug-in electrics, which get 50-100 miles per multi-hour charge, are the wave of the future.
In general, let’s go back to that E30 concept. With an engine compression that’s tuned for E30, there’s no material loss in mileage, or range.
One last one – shouldn’t we be building electrics, if we want to really, really focus in on just one platform?
Here’s the National Research Council view [ISBN: 0‐309‐14851‐0, 70 p. (2010)]: the high cost of batteries, limited availability of places to plug in, competition from other vehicles, consumer resistance to plugging in virtually every day and continuing government support for several decades are problematic barriers to near-term adoption of electrics.
Regarding the effect on oil consumption the report concludes: “PHEVs will have little impact on oil consumption before 2030 because there will not be enough of them in the fleet. More substantial reductions could be achieved by 2050 but will reduce oil consumption only slightly more than can be achieved by just the hybrid vehicles (HEVs)”.
Bottom line, electrics may well be the 2050+ future, but carbon and energy dependency concerns dictate the development of deep-impact solutions that apply to the nearer term – and that means liquid fuels.
Onto Biomass 2011, and some further reading.
So – that’s the case for ethanol – its distribution barriers can be overcome, and should not distract us from its higher yields. We’ll be highly interested in how the debate shakes out at Biomass 2011 when the formidable Rick Wilson takes the microphone in defense of drop-in fuels.
Category: Fuels
