Note on Algal Biofuels
Here’s the latest installment of my colleague Jon LeSage’s Green Auto Digest, which includes a fairly full treatment on algae biofuels. He believes they’re at a critical juncture as a viable clean transportation fuel, and writes:
A few years ago, algae biofuels and oils looked like ideal options for the future of clean transportation.
For those objecting to corn-based ethanol, or concerned about traditional biodiesel, algae fuel was showing a lot of promise for passenger cars and commercial vehicles. Appealing factors have included emission reductions and the ability to tap into the renewable fuels and oils through plants. Lately, the future of algae biofuels has become open to debate and may stand a better chance of succeeding in other markets beyond automotive and transportation. However, algae fuel still has several deep-pocket investors and industry groups supporting it as a clean fuel option….………
I respond:
Hi, Jon.
It looks to me that your “pros and cons” are exclusively “pros.” Personally, I’m not at all bullish, for three main reasons:
• Track record: many hundreds of attempts to create algal biofuels cost-effectively over several decades hasn’t produced any results that would suggest that success is in our future. I know there are claims to the contrary, but there is no reason to believe they’re true.
• Thermodynamics: As I’ve argued here and many other places, plants evolved over billions of years in such a way to make the whole enterprise of energy extraction a real problem.
• Competitive landscape: All this is happening during a time in which electric transportation is becoming stronger every day, especially in terms of cheaper, better batteries.
I know there are those who consider algal biofuels a solid cleantech investment opportunity, but I’m not one of them.
Of course, I respect your viewpoint, and I’m quick to point out that I’ve been wrong once or twice in my life. 🙂
Thanks for the wonderful newsletter; it’s quite a service you provide.
Probably there will always be a need for liquid fuels even if all of surface transportation is electrified. It is unlikely that air planes could ever be battery powered since batteries lack sufficient energy density, so airplanes will probably always need liquid fuels.
Of course making bio fuels practical would be exceedingly challenging. Plants, including algae, evolved only to be successful at surviving and multiplying for which converting sunlight efficiently into high energy tissue is not necessary. I don’t know what the exact efficiency is, but I’d guess it to be less than 10%. Then, there would be losses in processing the plants into fuel. Perhaps a way could be found, but it does not look very promising.
While it is true that present batteries lack the energy density of hydro carbon fuels there is that annoying example of the round the world flight using electricity alone: http://www.solarimpulse.com/ It passed the milestone of 24 hours of flight using no fuel several years ago. I am less “dismissive” for the future of electric flight. And aircraft builders seem to agree: http://www.scientificamerican.com/article/impossible-electric-airplane-takes-flight/
Some technologies that are less useful for electric vehicles can find a better application with electric flight. Planes do have the ability to fly above the clouds where insolation is going to be less “intermittent.” They have a huge surface area on their wings which makes them an entirely different vehicle than an electric car. PV panels can give aircraft the generating capacity to obviate the need to completely carry stored energy on the flight. This will also tend to lighten the carrying weight required for the energy intensive take off. There are some less usual adaptations as well like putting electric motors in the wheels to assist with take off and landings.
Batteries built into the body panels of an electric car seems more risky than the same technology applied to electric flight. http://jalopnik.com/volvo-makes-an-electric-car-that-uses-body-panels-as-ba-1446996491 And lastly I have noticed recent advances in making electric motors lighter with the specific intent to use them in electric planes. http://www.flyingmag.com/aircraft/electric-future-why-electric-airplanes-are-poised-take-off
Once again technology seems to be in advance of public understanding and regulations: http://www.popularmechanics.com/flight/a4465/4330186/
That plane that flew around the world on electricity alone was simply performing a stunt. It flew only at very low speeds and was barely able to do even that. Even if PV systems were 100% efficient they could not provide sufficient power to make electric airplanes practical.
There may be an exception, i.e., a drone which could stay aloft for months at a time for military surveillance work. But except for such highly specialized applications, electric airplanes will never be practical. It’s a matter of physics.
Perhaps it would be best to compare apples to apples. So, Ok lets see. The Wright brothers plane flew 20 feet above the air. The flight lasted for 12 seconds and they covered a distance of a little more than 120 feet. (a little less than 7 mph) http://eyewitnesstohistory.com/wright.htm I am sure that when people heard about this they were saying that nothing would ever come of it… “If man had been intended to fly…”
The solar impulse has already demonstrated continuous flight (24 hours) It cruises at 40 mph and has circumnavigated the world using no fuel.
Perhaps you are thinking of something particular when referring to electric flight as “not practical.” There are even now private pilots purchasing electric airplanes and finding them extremely “practical” for entertainment purposes. Major companies are building electric planes and finding them extremely “practical” as demonstration and study vehicles for the future of electric flight. It seems almost as if you are saying that because electric airplanes cannot presently do “everything” they are not practical for anything.
Let’s try another approach.
We know that power increases with the cube of the speed, i.e., it takes EIGHT TIMES as much power to double the speed. If the Solar Impulse cruises at 40 mph, which is an impractically low speed, making it cruise at 80 mph, which is still too slow, would require EIGHT TIMES as much power.
Let us suppose that the PV panels which power the Solar Impulse have an efficiency of 16%, which is on the high side. If their efficiency were increased to 100%, which of course is impossible, the power would be increased by 6.25 times which is still to low to double the speed.
Considering the above, it is clear that solar powered airplanes are impractical except for some very specialized situations and will always remain so. The same would be true for battery powered planes which, although they may be able to attain a practical speed, would have very limited range.
This is not to say that they are useless, but rather, that their uses would be very limited. You won’t be flying for NYC to London on a solar or battery powered plane, but you might use a battery powered drone to inspect your estate and make sure the the game keeper is doing his job.
Sorry to interject (and I normally let stuff like this slide), but this is completely incorrect. Yes, in fluid dynamics, doubling the speed, perhaps of wind or water flowing through a turbine, provides eight times as much power. But it does not take eight time more power to double the speed of a moving object; these are two totally different animals.
Hi Frank,
Hmmm,…..” a battery powered drone to inspect your estate and make sure the the game keeper is doing his job”
It must be that time of night, but your suggestion made me ponder how such a device could have inspired the author D H Lawrence to better monitor the habits of gamekeepers 🙂
(Totally off topic, but I had a cousin who was the last landowner in the UK to have a gamekeeper flogged for Licentious, Lewd, Depraved and Unnatural acts.)
Thanks Craig for pointing out the relationship between power and speed. It is always interesting to hear your comments, not an intrusion.
Frank to my question about what you consider “practical” you seem to be looking for the mature technologies of commercial flight or I might add military use.
Fortunately, not everyone agrees that something that has not reached its mature potential and is currently in use, has no value. On this basis and to make the point we could say than that children have “no practical value.”
Support technologies, (like replacement parts for the human race) and R & D (like present electric aircraft) and even entertainment (like both) are practical goals, even if they are not economically viable ones.
It may be a rather shallow view of existence to insist that every effort should have an immediate positive dollar sign attached to it or it is “not practical.” It is this kind of thinking that leads to child labor and cutting funds for R & D even in the best of times.
Sunpower is the company that makes the Maxeon solar cells for the Solar Impulse. Their commercial cells are listed here with an efficiency of 21.5% https://us.sunpower.com/sites/sunpower/files/media-library/data-sheets/ds-x21-series-335-345-residential-solar-panels-datasheet.pdf I believe that the cells for the solar impulse were specially made. Like the solar cells for solar cars (for racing) they tend to be at the high end of what is technologically possible not just what is commercially available.
Electricity is coming to commercial flight. At first it is likely to be as some form of hybrid. Wheel motors to assist with taxing around airports, for take offs and landings are likely to be a start. http://www.marketwired.com/press-release/wheeltug-front-wheel-drive-for-airplanes-improves-aviation-ground-operations-1529193.htm http://www.electric-vehiclenews.com/2010/05/delos-aerospace-developing-wheel-motor.html
Somewhat the opposite of electric cars, electric power may then be used for cruising with take offs and landings continuing to be mostly fueled. This article says that the highest speed reached by electric flight has been 326 Km/h https://www.rt.com/news/203687-electric-aircraft-commercial-stage/
Solar panels will be used to recharge batteries or for direct power to flight as is economical and can be efficiently implemented. The solar impulse is a demonstration of what is possible not necessarily what is presently economically viable.
While it may be “clear to you” that the solar impulse is “impractical” I don’t think you can make the case that any technology will “always remain so.” This sounds more like the wishful thinking of a conservative dream.
I suspect, I might travel to London on an electrically powered flight long before I use a solar drone to “survey my estate,” but would be happy to accept either future.
Breath on the Wind
I don’t believe Frank is condemning the value of experimentation, or appreciation of the value of exploring new technologies.
I think Frank comments are directed to those who mistake an experimental flight, in contrived circumstances, as evidence that solar powered aircraft is feasible and imminent.
Not all technology can be up-scaled or survive beyond the laboratory. Just because a few exceptions succeed doesn’t mean every “potential” technology can be extrapolated to viability.
When the theory of”peak oil”, was at it’s apex, hundreds of billions of dollars was invested in attempting to find alternate Fuels.
Rapid, and disruptive increases in the price of fossil fuels and the growing popularity of environmental issues, also helped fuel investment. Way back in the 1970’s the Carter Administration had believed Ethanol production would prove to be a panacea for a number of problems.
The US was over producing corn, OPEC had proved it could drastically affect the price of oil, while smog was becoming a problem in large cities.
Ethanol seemed the ideal answer. Ethanol could restore US energy independence. Sadly, the world changed and ethanol production proved a ‘cure’ worse than the malady.
Likewise Algea and other methods of bio-fuel production. The environmental devastation wrought by trying to replace oil with bio-fuels worse than oil production. Economically, bio-fuels are as disastrous as they are environmentally.
There are exceptions. Several nations over producing sugar cane can economically and environmentally incorporate that surplus into the nations energy mix.
Bio-fuels still has very active, even fanatical, supporters. The supporters comprise those idealists who can’t give up the dream, and those with vested interests in the industry that’s been created. The fact that the industry only exists at the detriment of the taxpayer and consumers, doesn’t lessen the sense of entitlement by bio-fuel supporters.
The search for safe, economic renewable fuels will inevitably produce many promising technologies that turn out to be blind alleys.
This is true of most scientific endeavour. The real problem begins when a technology or scientific research becomes subverted to fit the dogma of a political or ideological philosophy.
Then ‘vested’ interests block other more worthwhile endeavours, while persisting trying to fit square pegs into round holes.
Craig I tend to agree with your assessment of biofuels. They are essentially a solar technology. PV is far more efficient than photosynthesis at converting solar energy to something more useful. But algae also give us energy storage as a fuel. Once again we have “artificial leaves” tend to be far more efficient than algae at giving us fuel. http://www.nytimes.com/2014/03/30/technology/the-artificial-leaf-is-here-again.html?_r=0 Algae is a bit more useful in that it gives us hydrocarbons rather than hydrogen. Hydrocarbons can be used in present vehicles. Algae is a technology that locks us into the past while other possibilities bridge us into the future. Algae promises us no new carbon into the atmosphere while other technologies give us no carbon solutions.
I have also speculated the effort is simply an attempt to use the energy market as a way to fund genetically modified organisms (the algae is a GMO) or a way to justify genetic engineering in general. I agree with Elon Musk that the industry has a bit of a fundamental flaw. http://www.businessinsider.com/elon-musk-doesnt-want-to-get-into-genetic-engineering-because-he-doesnt-know-how-to-avoid-the-hitler-problem-2015-6
Craig,
I made a mistake. The power to drive a vehicle increases with the SQUARE of the velocity, not the cube. Thus, doubling the velocity require FOUR times the power rather than eight times the power. Even so, increasing the efficiency of the PV planes on a solar powered airplane would still result in a speed which is impractically low for most purposes.
Frank I believe that you are unfairly limiting yourself by thinking in a little tiny box. There are a number of factors at play with the field of “alternative” airplanes. Electric flight is only a small part of a much bigger picture.
The formula you are trying to quote is derived from Newton’s second law of motion. http://www.physicsclassroom.com/Class/newtlaws/U2L3a.cfm The considerations get complex rather quickly. Here is a breakdown as it applies to acceleration when considering aerodynamic drag: https://spaceflightsystems.grc.nasa.gov/education/rocket/vel.html
Initially we are dealing with force (not power), mass, density, time and velocity.
When it comes to flight a consideration not usually as significant with cars is the air density. http://usatoday30.usatoday.com/weather/wdenalt.htm The higher we go the less dense is the air. This means less lift but also less drag. For conventional aircraft it is also a problem of getting enough oxygen for their engines. This is why the sweet zone for commercial flight is 30,000 to 35,000 feet. It is high enough to reduce drag but low enough to still give the engine enough oxygen.
Electric planes don’t need oxygen to operate their engines.
Instead of the brute force flying we do today, we could be using more finesse. Pilots of gliders are far more familiar with air currents and efficient flying than those who stick to power flight. http://www.avweb.com/avwebflash/news/gordon_boettger_glider_flight_record_sierra_wave_204759-1.html Without engines gliders have been able to travel over 300km/h and over 1750 km in distance: http://www.fai.org/record-gliding
Dynamic Soaring can give a tremendous boost to air speed. https://www.youtube.com/watch?v=xlPI0AOj5MI Just by using available wind, RC gliders have been clocked at 468 mph in a 68 mph wind. https://www.youtube.com/watch?v=rfoxjNg-eg0 With a little searching you will find another video recording over 500 mph. These aircraft are only using the wind to power the craft.
A mistake we often make when considering the future it to try and plug in a new technology into the present framework. Once we may have asked how a powered car is going to take us home from the pub like a horse can do for us. In this case, for 100 years the answer is that it will not, but we accepted drunk drivers in the trade off for other broad advantages.
You want to suggest that electric flight is not physically possible, but maybe we only need the assist of electric flight to get us up in the air. Previously I suggested that there were many hybrid potentials with fueled vehicles. There are also hybrid potentials with gliders. http://front-electric-sustainer.com/highlights.php
There is presently another test vehicle that is designed to travel to 90,000 feet using no fuel or engine. They believe they can travel that high using thermals updrafts. Another concept I have seen is to inflate a lighter than air bag to produce lift and then compress it at height to allow for soaring. With an air density about 2% that of sea level the craft is expected to reach speeds of up to 400 mph. http://finance.yahoo.com/news/airbus-perlan-mission-ii-glider-173400813.html
These are all legitimate test beds by substantial companies that are part of the pathway to the future of flight.