Aviation, both civil and military, together with the space industry generates an enormous amount of greenhouse gases, due to the fossil fuels burned by the planes, the jets, the missiles and rockets that launch satellites and spacecraft.
In the hydroegn economy, fuel cells in hydrogen cars can deliver clean electricity to the electric motors in such cars. However, a plane using conventional electric motors would quickly come too heavy, due to the weight of the magnets used in such motors. An electric motor using conventional magnets can weigh up to five times as much as conventional jet engine.
NASA and the Department of Defense therefore funded a team led by electromechanical engineer Philippe Masson of Florida A&M University and Florida State University to design an electric jet engine, using superconducting magnets.
Superconducting magnets would be less heavy, as well as more efficient and powerful for their size. They would generate three times the torque of a conventional electric motor for the same energy input and weight. Additionally, an electric aircraft would be far more quiet than a conventional plane, just like electric vehicles are silent compared to cars with internal combustion engines.
One problem is that such superconductivity occurs at extremely low temperatures. Ceramic YBCO (yttrium barium copper oxide) superconductors will carry electricity without resistance, producing a strong magnetic field without wasting energy, but they have to be chilled to 77 kelvins (–321 degrees Fahrenheit) or colder.
Masson suggests that, instead of carrying hydrogen compressed in tanks, planes could carry liquid hydrogen. To remain liquid, hydrogen must be kept at 20 K (or –424 degrees Fahrenheit), i.e. cold enough to make the superconducting magnets work. In other words, the cold of the liquid hydrogen could partly be used to chill the superconductor.
How much does liquid hydrogen weigh, compared to conventional aviation fuel? Masson and his colleagues believe that liquid hydrogen, used as proposed, has four times as much energy weight for weight than aviation fuel. Electrical propulsion would not only decrease greenhouse gas emissions, but would also "reduce to a minimum the needs for maintenance as all hydraulic systems would be eliminated", Masson says.
References:
Superconducting motors to help create all-electric aircraft
http://www.whatsnextnetwork.com/technology/index.php/2007/06/19/p5349#more5349
For Low-Emission Planes, Try Superconductivity
http://www.sciam.com/article.cfm?articleID=44F4DFC4-E7F2-99DF-3BE82FA1F437150A&chanID=sa026
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Comments: 27
Thanks again Sam...
, the prospects for fuel efficiency in air travel would seem also to favor a transition to these electric motors, fueled by hydrogen. I've read that the same one-two punch of carbon fiber composite/hydrogen is applicable to cars and light trucks as well.
Well said! Concise, accurate, comprehensive!
There is a system that will work on cars, planes and ships, that they have not looked at.
I once read Joe Romm's book "The Hype on hydrogen", in which he argues that hydrogen may be initially more useful in the role of storing energy in electricity production rather than in the role that has been heavily promoted of serving as a "fuel" in transportation. The problem that he saw is that it is hard to devise tanks for hudrogen that are safe and small enough and create an entire infrastructure for the "fueling"- (yes, hydrogen is not really a fuel, but is more of a means of storing and transmitting energy from one place to another)
What do you think of that argument?
Even Boeing studies indicates that the most cost effective future jet fuel is liquid hydrogen by way of nuclear energy, all others is cost prohibitive, even hydrogen by way of coal is too expensive. The next best step is jet fuel by way of bio-fuel.
1. Initially, that may be true, but it doesn't rule out hydrogen as a transportation fuel as fuel cells improve. The point Sam says (above) that cannot be emphasized enough is that "...we should not look at any of these new solutions in isolation...." Compare Lovins' comments (first paragraph).
2. Re: hydrogen tanks (Myth #7, p. 16).
and
Ovonic Hydrogen Solid Storage Technology Overview
Given the impact of aviation on global warming and its projected growth, we need a new tax, specifically on aviation. The tax should be higher, the more polluting the planes. Importantly, the proceeds should be used to subsidize the sales of airplanes that are least polluting. I'm not sure how long it will take to clean up aviation, but I'm convinced that this is the most effective way to deal with it.
There are other ways to store hydrogen, e.g. it can be compressed in gas tanks or it can be carried in solid form (see Amminex). But, as the article explains, it may well be attractive in the case of aviation to combine the cooling requirements of liquid hydrogen and superconducting magnets. Another advantage of liquid hydrogen is that it can be stored in relatively lightweight tanks. Anyway, my conclusion is that a switch to hydrogen would actually make air travel safer, as well as cleaner.
I couldn't help but notice that you didn't comment on the opinion of the world authority in aircraft manufacturing "Boeing" concerning powering aircraft with hydrogen, Is it that you believe you know better than they?
http://www.gather.com/viewArticle.jsp?articleId=281474977166023
"I'm not sure what "opinion" you're talking about"
That would be Boeing's opinion that the only economical way to produce hydrogen for aircraft usage is by way of nuclear power.
http://www.gather.com/viewArticle.jsp?articleId=281474977131568
But if you insist on bringing it up here, how much do you think Boeing's "opinion" on this is biased by the fact that it is part of the military-industrial complex that pushes nuclear "solutions"?
Are you perhaps suggesting I should put a photo of a Boeing aircraft at the top of this article, instead of an Airbus? I chose the Airbus 380, because it's the largest plane, using the most fuel. I would love to see Boeing become more realistic, Dan, and focus on the small plane market. It's time Boeing put more serious effort into its small hydrogen aircraft, as discussed in my article Wild Green Yonder, at:
http://www.gather.com/viewArticle.jsp?articleId=281474977166023
http://www.greencarcongress.com/2008/06/sumitomo-electr.html
Back in 2005, IHI had built a superconducting motor with the following features:
- lack of heat, moving parts and noise;
- small size and weight;
- possible double structuring of the motor shaft, enabling two motors to be connected in tandem and yet revolve in opposite directions.
http://www.ihi.co.jp/ihi/ihitopics/pressm_e/10003.html
This could be useful for a helicopter with two contra-rotating propellers
http://en.wikipedia.org/wiki/Coaxial_rotors