Is 85% the highest efficiency we can achieve with PV technology?

[gloo]

If there somehow was a way to produce electrical energy endlessly (as much as we want with no pollution or environmental issues), we still can't really say we can do away with oil anytime soon b/c of the inability to make high quality good batteries. First of all, there probably isn't enough Lithium in the world to switch all cars over right? Would we just start using whatever we can get our hands on then (Nickel Metal hydrate, lead acid etc...). Also, jets and airplanes wouldn't use electricity to propel themselves so we still need oilf for that right? Is there some liquid fuel (besides dangerous hydrogen) that electricity can be used to make abundantly?

 

[xxChrisxx]

Hydrogen isn't necessarily any more dangerous than any other form of liquid fuel (they all burn rather nicely). I can't think of any other potential gas fuel being made by electrolysis (off the top of my head anyway).

More than just for fuel, we can't eliminate oil completely as its used to create lubricating oild and plastics that are vital for planes/cars/machines etc. So those believeing that solving the energy crisis will instantly eleiminate the need for crude are foolish. However eliminating it as a primary source of fuel will go a hell of a long way to solving the CO2 and oil stock sustainability.

 

[gloo]

i thought i read somewhere that hydrogen has some chemcial characteristic that makes it very unstable and dangerous to handle (especially consumers pumping it into their cars), that made it too deadly?

Yeah, i was hoping that electricity in endless abundance would make oil as valuable as salt is today. I read about how they use to have wars over salt mines and that salt miners were given special status b/c of it's value in preserving food. Then with the coming of electricity and refrigeration salt ceased to exist as something of special value.

 

[xxChrisxx]

Nah, H2 isn't unstable, it is highly flammable, but doesn't explode when someone sneezes near it. There are already hydrogen fuel cell cars driving round (Honda FCX Clarity), so it's deemed safe enough for road use.

 

[gloo]

oh, cool - so if somehow we did find a cheap cheap way (cheap like hydroeletric dams or cheaper) to make electricity than oil would probably tank in price right away (as well as coal and nat gas i guess). The economy would jump towards hydrogen fuel cells right away right?

 

[xxChrisxx]

Well I personally think fuel cells are the future, combined with nuclear (fission for now/fusion when we crack it). It's slightly more complicated as fuel cells are still rather expensive, and a relatively new technology. It'll be quite a long time before it gets widespread use.

 

[MATLABdude]

Nah, H2 isn't unstable, it is highly flammable, but doesn't explode when someone sneezes near it. There are already hydrogen fuel cell cars driving round (Honda FCX Clarity), so it's deemed safe enough for road use.

I think the big problem with using straight hydrogen comes from hydrogen embrittlement of the pressurized steel tank that's used to store it (that and the fact that these tanks tend to be fairly heavy and bulky, for some given quantity of energy):
http://en.wikipedia.org/wiki/Hydrogen_embrittlement

My understanding is that most of these systems use some kind of liquid or solid compound from which hydrogen can be easily liberated (e.g. sodium or lithium borohydride, hydrazine--both of which have their own more easily handled issues)

 

[brewnog]

Is there some liquid fuel (besides dangerous hydrogen) that electricity can be used to make abundantly?

Absolutely.

http://en.wikipedia.org/wiki/Synthetic_fuel

 

[vanesch]

First of all, there probably isn't enough Lithium in the world to switch all cars over right?

Ah ? I didn't know that there was a problem with lithium supply ? Is that so ?

 

[gloo]

Ah ? I didn't know that there was a problem with lithium supply ? Is that so ?

I am not an expert - just read from some sources about how if we switch to lithium batteries for cars on a mass scale, it would put a big strain on lithium in the world b/c most of it is in China, and a lake bed in Chile. Could lithium be the new oil? Remember when people first found oil at the surface in the 1800's, it was this crazy annoying substance that everybody found as a pain in the *** to clean up. If they only had the foresight to buy up oil fields from the Arabs at cheap cheap prices.

 

[gloo]

Absolutely.

http://en.wikipedia.org/wiki/Synthetic_fuel

no sorry - i should have been more clear. I didn't mean fuels as a byproduct of making electricity. Rather is there a fuel (besides hydrogen) that applying electricity could make?

 

[Topher925]

Nah, H2 isn't unstable, it is highly flammable, but doesn't explode when someone sneezes near it. There are already hydrogen fuel cell cars driving round (Honda FCX Clarity), so it's deemed safe enough for road use.

Many advocates of H2 technology (including myself) believe that H2 is actually just as safe as many liquid fuels such as gasoline. This is mostly because it disperses extremely quickly. In the event of a storage tank leak, the entire contents of a 4kg H2 wt tank can be burned in a matter of a few seconds without detonation.

It's slightly more complicated as fuel cells are still rather expensive, and a relatively new technology.

Fuel cells actually aren't that "new". The first fuel cell was invented (1839) only about 30 years after the internal combustion engine (1807).

I think the big problem with using straight hydrogen comes from hydrogen embrittlement of the pressurized steel tank that's used to store it

My understanding is that most of these systems use some kind of liquid or solid compound from which hydrogen can be easily liberated (e.g. sodium or lithium borohydride, hydrazine--both of which have their own more easily handled issues)

The greatest challenges of using hydrogen as a fuel is its storage. Hydrogen is light weight but has a large volume which requires it to be pressurized to pressures greater than 5,000+ psi for vehicle applications. Many hydrogen storage tanks used in automotive applications don't use any metals. They are typically constructed out of a variety of plastics and carbon fiber which are immune to hydrogen embrittlment. The ones that do contain metals are lined with a high density polymer to contain the hydrogen.

The systems you are thinking of are hydrides. Hydrides work by storing H2 in the vacancies in their lattice structures which absorb and release hydrogen depending on the temperature, pressure, or humidity of the material. I know of no hydride system currently used in any fuel cell vehicle as they all suffer from poor power energy densities and long refueling times.

I am not an expert - just read from some sources about how if we switch to lithium batteries for cars on a mass scale, it would put a big strain on lithium in the world b/c most of it is in China, and a lake bed in Chile.

China has lithium? That is news to me. The largest deposits of lithium that we know of are in Bulgaria and South America (Chile I guess). Many prospect that with the use of lithium batteries for plug in hybrids we will be trading our oil problems in the middle east with lithium problems in the eastern and southern parts of the world.

 

[xxChrisxx]

Fuel cells actually aren't that "new". The first fuel cell was invented (1839) only about 30 years after the internal combustion engine (1807).

I just meant that with regard to its viability. Almost all decent ideas can be attributed to inventions 100's of years ago. Tbh I was actually surprised at just how many 'new' ideas were thought up at the turn of the century but shelved until the technology had been invented.

The greatest challenges of using hydrogen as a fuel is its storage. Hydrogen is light weight but has a large volume which requires it to be pressurized to pressures greater than 5,000+ psi for vehicle applications.

This is the only thing that makes me nervous about H2, I don't like the idea of sitting on a tank full of gas compressed to 340odd bar. I know with modern CF pressure vessels its pretty safe (it wouldn't be on the road otherwise) it still makes me nervous.

 

[mheslep]

Ah ? I didn't know that there was a problem with lithium supply ? Is that so ?

No. There's some question as to the long term availability of the cheapest Li coming out of Bolivia, but there's ample supply elsewhere (e.g. North Carolina US ) that is a little more expensive to access.
http://lithiumabundance.blogspot.com/"

 

[mgb_phys]

Could lithium be the new oil?

Generally it's less of a problem. Metals are rather more uniformly distributed, there are reserves that are higher concentration, more accessible or more developed. But compared to oil where the stuff is just pumped out of the ground in it's raw state smaller sources of metals can be mined profitably.

If they only had the foresight to buy up oil fields from the Arabs at cheap cheap prices.

We did, before it was called BP it was called the Anglo-Iranian Oil company. We had to gas a few locals, start a couple of minor wars and do a bit of regime change but all that was 100 years ago - doesn't happen like that now.

 

[Integral]

I am puzzled?

This thread discusses Hydrogen and Li as if they were a source of energy. They are not, what they are is energy storage mechanisms. In order to use H you must produce it, a Li battery must be charged both require energy. The energy to produce H or charge a Li battery must come from somewhere so while better energy storage is important it is not nearly as critical as finding ways to PRODUCE the energy.

If we do not find a replacement for fossil fuels in the next decade you youngsters may live to witness the end of civilization as we know know it. Currently algae based bio fuels are the brightest stars on the horizon. We need to find more and better ways to convert sunlight to power along with improved energy storage mechanisms.

 

[mgb_phys]

No, the OP asks if we had an unlimited source of energy 'too cheap to meter' would we then be in exactly the same situation as now but competing for the materials to make batteries rather than for oil.
And is there an alternative to hydrogen for systems that cannot use batteries (like aircraft).

 

[mheslep]

... Also, jets and airplanes wouldn't use electricity to propel themselves so we still need oilf for that right? ...

That is what I thought as well until I saw this recent work on electric ducted fans, posted in another thread.
https://www.physicsforums.com/showpost.php?p=2292842&postcount=14
If those happen no doubt they'll start out with traditional onboard gas turbine electric generators, but eventually other electric sources are possible as their specific energy improves including fuel cells, batteries, even nuclear.

 

[russ_watters]

If we do not find a replacement for fossil fuels in the next decade you youngsters may live to witness the end of civilization as we know know it.

We likely have enough fossil fuels to last us a couple of centuries, it's just that using them will be expensive. It will certainly change the economy, but it won't be drastically different than what we have now.

If oil prices end up double or triple (or more) what they are now in a few decades due to lower supply, that'll open up vast new sources of oil for economic viability. Decades after that, if oil prices double or triple (or more) again, then we'll be converting our vast supply of coal to liquid fuel burnable in vehicles. This in turn will make coal use in power plants too expensive and make nuclear power the only viable large scale power source.

Will cars be powered by liquid hydrogen, lithium (or other) batteries or a synthetic liquid fossil fuel in 100 years? I'm not all that worried about these possibilities because I don't see the technical hurdles as being all that daunting. These are largely economic issues.

 

[Integral]

We likely have enough fossil fuels to last us a couple of centuries, it's just that using them will be expensive. It will certainly change the economy, but it won't be drastically different than what we have now.

If oil prices end up double or triple (or more) what they are now in a few decades due to lower supply, that'll open up vast new sources of oil for economic viability. Decades after that, if oil prices double or triple (or more) again, then we'll be converting our vast supply of coal to liquid fuel burnable in vehicles. This in turn will make coal use in power plants too expensive and make nuclear power the only viable large scale power source.

Will cars be powered by liquid hydrogen, lithium (or other) batteries or a synthetic liquid fossil fuel in 100 years? I'm not all that worried about these possibilities because I don't see the technical hurdles as being all that daunting. These are largely economic issues.

Russ,
Those are your conservative beliefs. Others believe differently. I do not like putting the our children's futures at risk simply because it is easy for us. We need to wean ourselves from fossil fuels, the sooner the better. To deny this is simply foolishness. Putting your faith in the undiscovered resources is simply silly. A much healthier belief system would be one which puts the development of alternative fuels on the front burner, NOW.

 

[russ_watters]

Those are your conservative beliefs. Others believe differently.

Agreed, but since you did not feel the need to put a "these are my liberal beliefs, others believe differently" disclaimer on your post, I didn't see a reason to put a similar one on mine!

I do not like putting the our children's futures at risk simply because it is easy for us.

Agreed!

We need to wean ourselves from fossil fuels, the sooner the better.

Agreed!

To deny this is simply foolishness.

Agreed!

Putting your faith in the undiscovered resources is simply silly.

Agreed!

A much healthier belief system would be one which puts the development of alternative fuels on the front burner, NOW.

Why not skip the development and go straight to the implimentation, since we have plenty of alternatives right now that can have a huge impact on the problem?

...btw, how does your position that we should work on development jive with your opinion that we shouldn't put faith in undiscovered resources? Instead of unidscovered resources, you're putting your faith in undiscovered technologies! Why I think my ideas are superior to most peoples' is that my ideas do not require undiscovered resources or technology for quite a while whereas most peoples ideas require undiscovered resources or technology right now. Every second (and dollar) we spend pursuing ideas like solar power instead of building a new nuclear plant (for example) is a second (and dollar) wasted.

 

[mheslep]

... Every second (and dollar) we spend pursuing ideas like solar power instead of building a new nuclear plant (for example) is a second (and dollar) wasted.

Jumping in here - allright, but your prior post was a plan that only sanctioned fossil fuels. Perhaps you were referring only to transportation needs, but it seems your proposal for transportation energy would still have us indefinitely importing oil from maniacs, and would dismiss harm from emissions? I don't buy into the latter entirely, but neither do I recommend indefinitely dumping the yearly emissions from a cubic mile of petroleum into the atmosphere.

 

[xxChrisxx]

For transportation 2nd generation biofuels are the best stopgap until a cheap and clean source of electricity can be found to supply H2. They are made from parts of the crop that aren't eaten and are almost carbon neutral. Problem is, they are expensive to produce making them uncompetetive with crude based fuel.

You still need crude for lubrication and plastics though (as far as I can remember anyway).

 

[mheslep]

For transportation 2nd generation biofuels are the best stopgap until a cheap and clean source of electricity can be found to supply H2. They are made from parts of the crop that aren't eaten and are almost carbon neutral. Problem is, they are expensive to produce making them uncompetetive with crude based fuel...

1) Biofuels. The Biofuels vs EV's future has yet to be decided. Good debate between biofuel and electric vehicle commercial advocates in the Economist:
Proposed:
This house believe that biofuels, not electricity, will power the car of the future.
http://www.economist.com/debate/overview/145
Audience voted it down 68:31.

2) Hydrogen. The big R&D is dead for now. Interview with DoE Secretary Chu:
http://www.technologyreview.com/business/22651/page2/

TR: The hydrogen fuel-cell program has been scaled back in the proposed budget, and the emphasis has been changed from transportation to buildings.

SC: That's right.

TR: It used to be thought, five to eight years ago, that hydrogen was the great answer for the future of transportation. The mood has shifted. What have we learned from this?

SC: I think, well, among some people it hasn't really shifted [laughs]. I think there was great enthusiasm in some quarters, but I always was somewhat skeptical of it because, right now, the way we get hydrogen primarily is from reforming [natural] gas. That's not an ideal source of hydrogen. You're giving away some of the energy content of natural gas, which is a very valuable fuel. So that's one problem. The other problem is, if it's for transportation, we don't have a good storage mechanism yet. Compressed hydrogen is the best mechanism [but it requires] a large volume. We haven't figured out how to store it with high density. What else? The fuel cells aren't there yet, and the distribution infrastructure isn't there yet. So you have four things that have to happen all at once. And so it always looked like it was going to be [a technology for] the distant future. In order to get significant deployment, you need four significant technological breakthroughs. That makes it unlikely.

Edit: also from Chu:
http://climateprogress.org/2009/05/07/secretary-steven-chu-doe-hydrogen-budget/"

“We asked ourselves, ‘Is it likely in the next 10 or 15, 20 years that we will covert to a hydrogen car economy?’ The answer, we felt, was ‘no,’” Chu said in a briefing today. He cited several barriers, including infrastructure, development of long-lasting portable fuel cells and other problems.

 

[Integral]

Agreed, but since you did not feel the need to put a "these are my liberal beliefs, others believe differently" disclaimer on your post, I didn't see a reason to put a similar one on mine! Agreed! Agreed! Agreed! Agreed! Why not skip the development and go straight to the implimentation, since we have plenty of alternatives right now that can have a huge impact on the problem?

...btw, how does your position that we should work on development jive with your opinion that we shouldn't put faith in undiscovered resources? Instead of unidscovered resources, you're putting your faith in undiscovered technologies! Why I think my ideas are superior to most peoples' is that my ideas do not require undiscovered resources or technology for quite a while whereas most peoples ideas require undiscovered resources or technology right now. Every second (and dollar) we spend pursuing ideas like solar power instead of building a new nuclear plant (for example) is a second (and dollar) wasted.

The difference is similar to laying under the apple tree waiting for the fruit to fall into your mouth rather then getting up and taking action.

I am amazed that you cannot see the difference.

BTW we are off topic with this conversation.

 

[xxChrisxx]

Well whoever the fella is, I don't share his views. I am of course no one of authority but my views are scientific FACT! :P

Hydrogen is the only really obvious choice for long term fuel, once you've got the infrastructure nailed and have carbon free electricity then its the obvious choice. The technology is there, just that no one wants to stump up the cash.

All of the above arguments hinge on the fact that you are burning fossil fuels for H2, which for the moment is true, but a progressive switch to nuclear and (shudder) wind/solar etc will solve that in a jiffy. That and atm its expensive to implement, but then again so are biofuels. Biofuels have less inital expendature but refinement of the technology isn't likely to reduce the cost by a great amount.

The more availalbe cheap electricity is, the cheaper H2 is.

 

[mheslep]

Well whoever the fella is, I don't share his views. I am of course no one of authority but my views are scientific FACT! :P...

He's a nobel laureate in physics and the US Secretary of Energy. Also, save your self some trouble and re-read the https://www.physicsforums.com/showthread.php?t=5374".

 

[xxChrisxx]

He's a nobel laureate in physics and the US Secretary of Energy. Also, save your self some trouble and re-read the https://www.physicsforums.com/showthread.php?t=5374".

Specifically regarding?

 

[mheslep]

specifically regarding?

pwa:

2) citations of sources for any factual claims (primary sources should be used whenever possible).

 

[xxChrisxx]

pwa:

Did you not see the little ':P'. You must have done as you quoted it.

That is a cheeky emoticon, and is put after the claim that it is a 'fact' to indicate that I was in fact (many uses of the word fact) saying it in jest. The fact that I both capitalised FACT! and immediately before said I was no authority on the subject showed that it was my opinion. I have ealso stated that it was my opinion earlier in this thread.

If I had claimed that it was serious fact that I had invented a car that runs on sneezes, then you may possibly hae had a case.

IBTL.

DISCLAIMER: This post, although sarcastic, is in no way meant to be hostile.