at a green festival last month. No doubt they are sincere. However, they have the same problem as everyone else. There are no biofuels available in commercial quantity that don't do more environmental damage than the fossil fuels they replace. It's a bit of a paradox. He talked up algae as the great green hope but also thought that today's food based fuels would be an OK bridge. Sound familiar?

Turbine engines should have few problems burning biodiesel blends. Jet engines just are not very picky about what you feed them. You can't use it legally until the FAA has approved it. Safety is all important in aviation. Cold temperatures that could cause biodiesel to become overly viscous is probably the main concern, along with microbes growing in the fuel. From the linked to article:

Boeing expects planes to operate on a 30% blend of biofuel. It also believes they could operate on a 100% blend, but says there would not be enough biofuel to supply an industry that consumes 85bn gallons of kerosene a year.

That will be a 30% blend of soy, canola, or palm oil, guaranteed.

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

http://switchboard.nrdc.org/blogs/lizbb/charting_a_greene ...

please read, it articulates quite clearly where aviation is headed.

Its all about transparent, independant, auditable supply chains that meet these criteria.  Via the RSB process, clear, actionable sustainability practices can and will be in place.  RSB is slow and painful, but it will result in solid standards.

Its unlikely that canola, soy, palm will make the cut owing to the type of land needed, but you miss the point.  EPA will shortly come out with a ruling that soy biodiesel won't qualify for the RFS, owing to land use change--just one for instance of how things are going. Feedstocks aren't the problem, its really quite specific to where and how a feedstock is grown and that can and will be determined by end users demanding sustainability.

are there never going to be downsides?  Of course not. Its about bringing smart, knowledgeable people, who don't have an interest in biofuels per se, into the process for setting up these supply chains.

The current missing link is end users enforcing sustainable supply chains using independant auditors.

this is what corn ethanol, palm and soy folks paid no attention to. They got it wrong, and now its time to do it right.

And counter to your assertion, in fact there are many attractive terrestrial options that will work well on non food crop land where there is low biodiversity value.  Algae will be great if/when the technical hurdles are solved, but its not all about algae either.

you are probably not plugged in, and thats fine, you will become aware in time...

http://www.businessgreen.com/business-green/news/2228012/ ...

I see it coming now. The airline industry, hell bent to keep its fuel supplies, jumps into the fray. Air travel as we know it today will become a much rarer occurance, biofuels or no biofuels.

The NRDC uses the argument that if we don't give the airlines biofuels, they will  use oil from tar sands! That's ridiculous. They will use whichever is cheaper. Why don't they work to shut down the tar sands instead of promoting more agriculture? It's irrational.

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

Air travel can survive only when powered by fuel-cells. Batteries have too low energy density, and wouldn't make it.

There are three options for fuel cells : Hydrogen, Boron gas, and syn-fuels based on hydrocarbons.

Hydrogen would make a good choice only if the airplanes are redesigned as blimps (slower, but more comfortable travel). This is also more fuel efficient. Compressed Hydrogen takes up too much volume, which will be uneconomical in normal airplane designs.

The second option is Hydrocarbon based syn-fuels. These are the easiest way out, they do not require redesigning the engines. But producing these kind of fuels sustainably is a big problem. We can incinerate biomass, or cultivate algae over ponds, or grow energy plants for cellulosic ethanol. All of these take too much land, water and sometimes (nuclear or fossil fuel) energy inputs. In any case, hydrocarbon based air travel becomes feasible only if we sacrifice several other uses of hydrocarbons, such as in road travel or in fertilizers. Further, if adopting such a strategy, we should be on the lookout for biodiversity abuses.

The third option is fuel cells powered by Boron gas. This is very interesting, because the energy density of Boron is very high, both per volume and per mass. This makes it a good carrier for fuel cells. Already, Boron slurry is used in some forms of rocket ignition and jet fuels. Airplanes should pump in some money to investigate the use of Boron fuel cells. Used up Boron (Boria) can be treated with nuclear / solar power and reconverted to fuel cells.

Personally, I like the third option the most.

Let's think in terms of eco-dollars.

With cars you can accomplish much more by improving gas mileage--24 mpg Outback vs 48 mpg Prius or the new 50 mpg Insight--than by trying to replace what is in your tank with biofuels. Biofuels are not what you call a low hanging fruit. Even if we find versions of these fuels with acceptably low environmental impact, they will remain expensive and precious.

However, that idea does not scale to airliners, which can't achieve similarly huge improvements in mileage. Unlike cars, gas mileage has always been a critical part of the design envelope.

They will always consume gargantuan amounts of fuel because the whole idea behind air travel is speed, and speed requires overcoming drag, and drag is an exponential function of speed.

Electrification is also not an option for aviation.

Short of finding some substitute for an incredibly dense and relatively inexpensive liquid source of energy that you simply pump out of the ground and crack, air travel is going to undergo a major contraction as peak oil slams home (airline tickets are going to get even more expensive). General aviation went through a huge contraction from its heyday and we managed to adjust just fine.

I don't see that as the end of the world. Biofuels can't fix that because they won't be cheap. Roughly 40% of the cost of your airline ticket is the fuel you will burn. If you pay $400, about $160 is for the fuel you will consume on your journey.

http://www.gfn.com/sowhatsyourpoint/wp-content/uploads/2008/07/airline-fuel.jpg

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

real time: the liquid coal and tar sands folks are fighting for massive subsidies.  more coal folks than tar sands.  the arguement the coal guys are making is lower carbon options arent going to be real, ever, so just give us (liquid coal people) all the $$ for subsidies. This isn't an abstraction, its quite real

So, why doesn't the NRDC put all of their time and money into fighting those subsidies? What logical sense does it make to instead fight for subsidies for other fuels so they can compete against other subsidized fuels?

I'm all for fuel substitute research. I'm not for subsidies and mandates for carbon sink/biodiversity destroying food usurping biofuel production (which exist primarily because they buy votes).

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

I'm getting pretty off topic.

Most people mean well. It's hard for many environmentally conscious types to believe that  coal and nuclear proponents really believe that their livelihood is truly a good and needed product that makes people's live better, but they do, as do corn ethanol famers, palm oil plantation owners, and on and on and on.

Is it possible that Hitler thought he was doing the right thing? I strongly suspect he did. And please people, I'm not comparing any individual to Hitler here. Also, Godwin's Law only argues against overuse of Hitler comparisons, not the elimination of them.

My point is that it really does not matter a wit if you have good intentions. The road to hell blah, blah.

We are all susceptible to our human natures. Rationalization bias is with us every waking hour and probably in our dreams as well. All we can do is present our arguments.

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

That remark didn't add a whole lot to the discussion. Wasn't it you, or whoever it is that shares that moniker with you, who was told to

"Quit labeling people who disagree with you as fascists?"

And you were not particularly apologetic about it. No sir, when you call someone a fascist, you mean it. I recall when you accused one of your professors of being a fascist along with various and sundry members of the United Nations as well.

And nice try on the Hitler accusation, but I made it perfectly clear that I was not comparing anyone to Hitler.

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

This is a bit late and endangers the cease fire that David seems to have won with his "cool it" yesterday but I only saw this comment string this evening and want to clarify a few things.

As the author of the Switchboard blog at issue, I want to say emphatically that we are "busting our butts" to borrow again from David to fight the tar sands and other dirty fuels and all the subsidies that are going or might have gone to support them. Go to our dirty oil page - http://www.stopdirtyfuels.org - for the latest. This fall we fended of a repeal of Section 526 of the new energy bill of 2007 and numerous other dirty fuels amendments. Sadly, a nearly billion dollar subsidy for expanding tar sands and oil shale refineries got through as part of the tax extenders package that was hitched to the bailout bill.

But we ARE there - that is the main focus of our  work. That said, we are also putting energy into creating alternatives. I totally agree that there can be a serious debate about air travel but the reality is there is going to be air travel and the sector is growing so we should do what we can.  

Please do read through the Sustainable Aviation Fuel Users group pledge, which you can see on my Switchboard blog (switchboard.nrdc.org/archive_bydate.php?ym=200809 - 36k), which lays out the criteria for these next generation fuels. Oil - and tar sands oil especially - would flunk out right out of the gates. It would be pretty amazing to see a fuel come onto the market that could meet all the criteria laid out by SAFUG and the RSB.  

And we better keep an eagle eye on aviation. The Air Force is really pushing these dirty fuels - especially liquid coal - and the Commercial Aviation Alternative Fuel Initiative (CAAFI) is trying to certify a mixture of coal and biomass.       We want to see a strong alternative out there. Hopefully, SAFUG (inspiring acronym, eh?) can do it.

Thanks all. It was fun reading your posts. Just glad my colleague Ian Wilker caught the back and forth about NRDC's work in this area so I could dive in.  

Liz Barratt-Brown