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What Will Be The Next Portable Energy?  
User currently offlineDocLightning From United States of America, joined Nov 2005, 20358 posts, RR: 59
Posted (3 years 4 days 3 hours ago) and read 1440 times:

So at some point, combustion is going to have to go. Either we're going to run out of fossil fuels, mess up the planet to the point where we actually have to stop, or move somewhere without a ready supply of oxygen.

When that happens, energy will probably be generated mostly by nuclear fusion I'd imagine. But how will energy-dense mobile requirements be met?

Today, the most efficient way to transport energy is with fuel. Short of nuclear fuel (which has an enormous energy density by mass but requires even more enormous reactors to extract it), hydrocarbon fuels have the highest energy density per mass of any form of energy storage. This is why it runs cars, ships, trains, and planes.

Will it be supercapacitors? Will it be hydrogen/oxygen from hydrolysis? Something more exotic?

How would you power an airplane on Mars? Hydrazine?

14 replies: All unread, jump to last
 
User currently offlinedfwrevolution From United States of America, joined Jan 2010, 1001 posts, RR: 51
Reply 1, posted (3 years 4 days ago) and read 1345 times:

Quoting DocLightning (Thread starter):
So at some point, combustion is going to have to go. Either we're going to run out of fossil fuels, mess up the planet to the point where we actually have to stop, or move somewhere without a ready supply of oxygen.

If we were serious about reducing oil consumption, we would substitute natural gas for transportation fuels like gasoline, diesel, and kerosene. No one alive will live to see the day when we will run out of natural gas. There is a stupid amount of proven natural gas and discoveries are outpacing production. Natural gas is a step-change cleaner and more economical than gasoline and diesel.

There is no reason to believe we will "actually have to stop" burning fossil fuels.


User currently offlinetugger From United States of America, joined Apr 2006, 5797 posts, RR: 10
Reply 2, posted (3 years 4 days ago) and read 1341 times:

Quoting DocLightning (Thread starter):
Will it be supercapacitors? Will it be hydrogen/oxygen from hydrolysis? Something more exotic?

Tiny jet turbine generators built on the nano level. They'll be small enough to fit inside button-cell battery size-shape.

Tugg



I don’t know that I am unafraid to be myself, but it is hard to be somebody else. -W. Shatner
User currently offlinedfwrevolution From United States of America, joined Jan 2010, 1001 posts, RR: 51
Reply 3, posted (3 years 4 days ago) and read 1335 times:

Quoting DocLightning (Thread starter):
When that happens, energy will probably be generated mostly by nuclear fusion I'd imagine. But how will energy-dense mobile requirements be met?

I guess I'm being a bad sport by saying combustion will all out live us. Playing along now...

It's not an unreasonable assumption that chemical batteries will continue to improve in power density. High-strength materials are continuously becoming stronger, lighter, and more economical. Compressed gas could be a feasible energy storage method.

Quoting DocLightning (Thread starter):
How would you power an airplane on Mars? Hydrazine?

Mars mission architect Robert Zubrin has advocated the use of a Sabatier reaction to produce methane and oxygen from hydrogen and CO2 in the Martian atmosphere. From our current understanding of the Mars hydrosphere, you would still need to bring the hydrogen to Mars, but 8 tons of LH2 would yield 112 tons of oxidizer/propellant.


User currently offlineDocLightning From United States of America, joined Nov 2005, 20358 posts, RR: 59
Reply 4, posted (3 years 3 days 21 hours ago) and read 1294 times:

Quoting dfwrevolution (Reply 1):

If we were serious about reducing oil consumption, we would substitute natural gas for transportation fuels like gasoline, diesel, and kerosene. No one alive will live to see the day when we will run out of natural gas. There is a stupid amount of proven natural gas and discoveries are outpacing production. Natural gas is a step-change cleaner and more economical than gasoline and diesel.

If we are, say, colonizing mars, then that won't work. Even if there were natural gas there (and there isn't), there's no oxygen.


User currently offlineDeltaMD90 From United States of America, joined Apr 2008, 7980 posts, RR: 51
Reply 5, posted (3 years 3 days 21 hours ago) and read 1292 times:

I'm rooting on algae. Some report 'said' (take that how you want it) that it will be viable around 2018. It creates CO2 but sucks up CO2 when produced. It can be farmed on arid land (or anywhere really,) even using sewage. It produces more fuel and at a faster rate than other bio fuels. Go algae!!!!!!!!!!


Ironically I have never flown a Delta MD-90 :)
User currently offlineLGWflyer From United Kingdom, joined Mar 2011, 2348 posts, RR: 1
Reply 6, posted (3 years 3 days 21 hours ago) and read 1290 times:

Quoting DeltaMD90 (Reply 5):
I'm rooting on algae. Some report 'said' (take that how you want it) that it will be viable around 2018. It creates CO2 but sucks up CO2 when produced. It can be farmed on arid land (or anywhere really,) even using sewage. It produces more fuel and at a faster rate than other bio fuels. Go algae!!!!!!!!!!

Sounds interesting! Might have a look on google for some info about it.



3 words... I Love Aviation!!!
User currently offlineDocLightning From United States of America, joined Nov 2005, 20358 posts, RR: 59
Reply 7, posted (3 years 3 days 21 hours ago) and read 1285 times:

Quoting DeltaMD90 (Reply 5):
I'm rooting on algae. Some report 'said' (take that how you want it) that it will be viable around 2018. It creates CO2 but sucks up CO2 when produced. It can be farmed on arid land (or anywhere really,) even using sewage. It produces more fuel and at a faster rate than other bio fuels. Go algae!!!!!!!!!!

Vertical photobioreactor-grown algae is the way to go. The big problems are scaling the production facilities up enough to produce enough fuel (it would take a few hundred acres of desert somewhere) and the fact that the algae grow SO quickly that they actually need to be fed concentrated CO2. You can't just blow air through the bioreactors.


User currently offlineDeltaMD90 From United States of America, joined Apr 2008, 7980 posts, RR: 51
Reply 8, posted (3 years 3 days 21 hours ago) and read 1281 times:

Quoting LGWflyer (Reply 6):
Sounds interesting! Might have a look on google for some info about it.
http://en.wikipedia.org/wiki/Algae_fuel

And IIRC, that Continental flight a few months ago that was 100% biofuel was algae. I *think*



As far as mass produced energy, I foresee wind and solar and all picking up, but I think the big breakthrough will be cold fusion...



Ironically I have never flown a Delta MD-90 :)
User currently offlineDeltaMD90 From United States of America, joined Apr 2008, 7980 posts, RR: 51
Reply 9, posted (3 years 3 days 20 hours ago) and read 1261 times:

Quoting DocLightning (Reply 7):
SO quickly that they actually need to be fed concentrated CO2.

Oh, then just build them in Pittsburgh      



Ironically I have never flown a Delta MD-90 :)
User currently offlineAustrianZRH From Austria, joined Aug 2007, 1408 posts, RR: 0
Reply 10, posted (3 years 3 days 14 hours ago) and read 1238 times:

I think the LS9 approach is quite promising (using cellulosic biomass as feedstock for biofuels created by genetically designed bacteria).

www.ls9.com



WARNING! The post above should be taken with a grain of salt! Furthermore, it may be slightly biased towards A.
User currently offlinekpitrrat From United States of America, joined Oct 2011, 194 posts, RR: 0
Reply 11, posted (3 years 3 days 14 hours ago) and read 1237 times:

The way this world is going.....Wood.

[Edited 2011-12-22 23:33:05]

User currently offlineqf002 From Australia, joined Jul 2011, 3020 posts, RR: 2
Reply 12, posted (3 years 3 days 10 hours ago) and read 964 times:

Heat induction... Your mobile phone sits in your pocket all day, absorbing the heat that your body radiates, why not find a way to turn that heat into the electricity that powers it?

User currently offlinejollo From Italy, joined Aug 2011, 241 posts, RR: 0
Reply 13, posted (3 years 3 days 6 hours ago) and read 934 times:

One possible and convenient way to quickly replace fossil fuels is through the so-called "methanol economy". Methanol is the simplest alcohol (CH3OH), liquid and stable at room temperature, and can be burned in internal combustion engines and turbines with very few modifications. It can also be transported and distributed with the existing transport infrastructure used for petroleum derivatives (pipelines, supertankers... down to the local gas station). So, unlike with hydrogen, you can switch to a methanol-based economy with minimal infrastructure changes.

Methanol can be produced from CO2, water and sunlight: basically, you electrolyse water using power generated by a solar panel (2 H2O + e → O2 + 2 H2), discard O2 in the atmosphere, put H2 in a reactor with CO2 taken from the atmosphere (needs a cheap metallic catalyser, plus some heath and pressure also powered by the solar panel) et voilà: CO2 + 3 H2 → CH3OH + H2O. Recycle H2O into the process (thus lowering H2O demand by 33%) and collect methanol for transportation.

Burning methanol and air (e.g. in an internal combustion engine) will create CO2 (2 CH3OH + 3 O2 → 2 CO2 + 4 H2O), but if it is produced with the above described process (getting CO2 from the atmosphere), the production-combustion cycle is carbon-neutral and leaves no pollutant by-products (aerosols, NOx, aromatic hydrocarbons, etc..).

Methanol does has a few problems to be worked around: it is highly corrosive for aluminium (and a few other metals, anti-corrosion treatments notwithstanding), so a few components along the whole cycle might have to be re-designed accordingly. Methanol’s specific energy density (19.7 MJ/kg) is less than half than gasoline's (46.4 MJ/kg), but packing a little less punch in your car engine will not kill anyone (in your aicraft engine that might be a slightly worse problem...  Smile but I'm confident ways around can be found). It is toxic if ingested, but not more than gasoline. On the other hand, unlike gasoline, it is very bio-degradable (7 days half-life in water).

The real problem is that feeding production with atmospheric CO2 gives very low production yields: you would need to crop the whole Sahara for sunlight and CO2 in order to compete with middle-east petrol production (just imagine the piping network needed to feed production with water!). So basically the only drawback is that jump-starting a methanol economy would be very capital-intensive: mind you, not a lot more than our petroleum-based economy, but much of that capital has been invested spread over a century or so. Another little problem is that current investors will not be very welcoming of a competing economy needing only sunlight, water and lots of free land...

But, if anyone wants to invest in the idea, I'm all for it!

Cheers!

[Edited 2011-12-23 07:16:44]

User currently offlineklaus From Germany, joined Jul 2001, 21521 posts, RR: 53
Reply 14, posted (3 years 3 days 2 hours ago) and read 891 times:

Quoting qf002 (Reply 12):
Heat induction... Your mobile phone sits in your pocket all day, absorbing the heat that your body radiates, why not find a way to turn that heat into the electricity that powers it?

The main problem with that is indeed interesting: It is already very much possible to extract energy from heat, but thus far only from a difference in temperatures, not from absolute heat.

The phone in your pocket is pretty much uniformly at body temperature (or not far from it). The temperature differential is too low to be exploited efficiently with current technology.

At least for planetary energy needs a converter which turns absolute heat into electrical energy would pretty much solve all our problems (a kind of thermal battery which gets cooler when you extract electric energy from it and which is powered by the absolute heat around it).

That would effectively be the holy grail of terrestrial energy – everything else is much more cumbersome. We "just" haven't discovered the way around the laws of thermodynamics which would be necessary for that. Not a piece of cake since you'd need to establish conditions outside of their base assumptions (ordered materials not just behaving statistically on the atomic and molecular level).

So unfortunately until someone cracks this problem, we'll probably have to settle for the usual methods (various electricity generation methods plus renewable sources of combustion fuels such as solar algae reactors).

For serious space exploration none of that would really "fly" since chemical fuels carry too little energy and even with hypothetical thermo-converters there would be too little thermal energy in most regions of space – some kind of nuclear energy source would probably be the only way to generate enough energy to efficiently travel in space. Star Trek proposed matter/antimatter reactions, but fusion or fission could theoretically work as well if the weight/mass requirements and the radiation problems of the respective reactors could be solved (don't hold your breath).


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