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CO2 capture


bascule

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To Lockheed

 

Very simple really. When the wind blows, you generate electricity. When you pump water uphill, or compress air instead, some of the energy is lost. Simple laws of thermodynamics. When the water flows downhill through a turbine, or the compressed air is released to drive a turbine, some more energy is lost, for the same reason.

 

End result is that you produce half, or less than half the amount of electricity compared to simply letting the wind turbine directly make electricity.

 

Much better to use wind power to produce hydrogen or synthetic methanol as fuel without any attempt to otherwise store energy. You cut out a very wasteful step.

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Liquid pumps (especially big industrial pumps) can easily reach 80% efficiency. My sources for this are Perry's Chemical Engineers Handbook (7th edition, section 10 page 25), and some mechanical engineers who are both my colleagues and friends. (Sorry that I cannot link to either of those). Small pumps suffer from problems in the electric engine where a lot of heat is created. But energy storage should at least store the energy output of 1 windturbine (2 MW peak power), so I consider this large.

 

The turbine also can reach the efficiency I stated in my previous post. 80% is feasible even for small scale turbines.

 

Actually, making hydrogen is also no 100% efficient process. Fuel cell technology (sustainable power -> electricity -> hydrogen -(fuel cell)-> electricity -> moving car) looks at 50% efficiency. Only very large systems can reach higher efficiency. (http://en.wikipedia.org/wiki/Fuel_cell - please look at "system efficiency" to see the efficiency of the entire cycle).

 

My personal conclusion is that hydro power is easier to use for energy storage. It is a proven technology that is already applied in cost-effective large scale projects (all hydro dams in the world). Fuel cells are a very good solution in transportation.

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To Lockheed

 

Very simple really. When the wind blows, you generate electricity. When you pump water uphill, or compress air instead, some of the energy is lost. Simple laws of thermodynamics. When the water flows downhill through a turbine, or the compressed air is released to drive a turbine, some more energy is lost, for the same reason.

 

End result is that you produce half, or less than half the amount of electricity compared to simply letting the wind turbine directly make electricity.

 

Much better to use wind power to produce hydrogen or synthetic methanol as fuel without any attempt to otherwise store energy. You cut out a very wasteful step.

 

Producing hydrogen or methanol are simply other ways to store the energy. Your comparison is only valid if you store it in one fashion and then use a different storage medium. insane_alien's point was about storing electricity for later use when demand exceeds the supply available (because it's night, or not windy, etc)

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Actually, making hydrogen is also no 100% efficient process. Fuel cell technology (sustainable power -> electricity -> hydrogen -(fuel cell)-> electricity -> moving car) looks at 50% efficiency. Only very large systems can reach higher efficiency. (http://en.wikipedia.org/wiki/Fuel_cell - please look at "system efficiency" to see the efficiency of the entire cycle).

 

Now compare to the traditional oil refinement process and the Otto engine

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Just a point about making hydrogen or synthetic methanol.

 

My logic is based on the assumption that such fuels will be needed and will be made. In terms of energy efficiency, it matters not whether the electricity used to make them is nuclear, hydroelectric, or wind power. In every case, there will be energy lost.

 

However, since wind power is erratic, and cannot be relied upon for steady electricity flows where that is needed, why not use it, instead of more reliable steadier sources, as the power for synthesizing fuels? Power such as nuclear can then be used where a steady supply is vital.

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Just a point about making hydrogen or synthetic methanol.

 

My logic is based on the assumption that such fuels will be needed and will be made. In terms of energy efficiency, it matters not whether the electricity used to make them is nuclear, hydroelectric, or wind power. In every case, there will be energy lost.

 

However, since wind power is erratic, and cannot be relied upon for steady electricity flows where that is needed, why not use it, instead of more reliable steadier sources, as the power for synthesizing fuels? Power such as nuclear can then be used where a steady supply is vital.

 

Why not indeed? That may be exactly how it plays out. But that assumes certain things about availability of power and logistics. It may turn out to be cheaper/more efficient to do it another way. I don't know offhand if methanol transport suffers from the same shortcomings as ethanol. But that may limit how much you produce in a particular area. Decentralized power production (e.g. solar at the home) means that the economies of scale aren't always in play, so it may not be efficient to produce fuel with that electricity, and once you put it on the grid, you can't tell where it came from. And if you simply don't have enough nuclear power (or other steady sources) locally available, you will have to have storage solutions for the other sources.

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This seems a relevant news article:

 

http://www.eetimes.com/showArticle.jhtml?articleID=206801669

 

It says that a new technology can do a hydrolysis of water to hydrogen (and, not mentioned in article: oxygen) at 85% efficiency. (Note: this is only the production of the hydrogen, not yet included is the conversion from hydrogen back to electricity).

 

This new technology is not yet on the market. First application (small batteries) are expected later this year.

 

My personal comment: 85% is nice, but a simple pump can do better.

 

 

Now compare to the traditional oil refinement process and the Otto engine

 

If you compare the energy contained in crude oil, and the kinetic energy you actually find back when you drive a car with a conventional combustion engine indeed makes you cry. It's about 20% I think, no more. I wish I had a decent reference to this... but I don't. - Anyway, for this discussion it seems not relevant, unless you were planning to make methanol for a normal combustion engine. That seems silly. It feels like buying a Ferrari and then putting a horse in front of it... :D

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To POM

 

As I have said before, and which is pretty obvious from a purely common sense viewpoint, there will not be any one single solution to the problems being discussed. There are probably a thousand research projects under way right now covering some aspect or approach. Most will go the way of the dinosaurs, and a few will survive and become part of 21st Century technology.

 

Electrolysing water to make hydrogen may or may not be a part of the group of technologies that develop. If it fails, it will not be a lack of water that is the cause. After all, there are 1,000,000,000,000,000,000 tonnes of water in the oceans!

 

Electric vehicles definitely should be one of the technologies. In fact, I predict EVs will become important in the very near future - the next few years. Today, many western families have two or more cars. This will continue, and one will be battery operated. Perhaps with a lower top speed and a lower range. But it will be ideal for commuting to work, and for shopping expeditions. It will be cheap to run. I believe that the time has come for the personal EV.

 

One thing I am sure of. The personal motor car will survive in some form or other. Not because it is more sensible or cheaper, or solves society's problems. It will survive because people WANT them.

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To POM

 

Not quite a strawman. What you said was :

"and if we tried to obtain all our hydrogen from existing freshwater supplies many European rivers would be running dry."

OK. This may not have been exactly what you meant, but it is what you said. In fact, there would be no need to desalinate sea water for electrolysis. Works well even with all that salt.

 

Your next statement

 

"exactly where are we going to be driving in these vehicles? They'll rush us silently and cleanly to the next traffic jam."

 

has several answers. For a start, not all cars are used in big cities. Also, proper extra road construction reduces the jams. Finally, new technology already on the drawing board will permit twice as many cars per unit motorway. For example : computer controlled auto-distance to the next car, permitting more cars per 100 metres, and adding to safety with electronic reflexes operating brakes etc.

 

"I WANT a replicator, a matter transmitter, a holodec... hey, let's just say I want a whole Enterprise to myself, as well as eternal youth, prosperity, happiness, and the same for all my friends"

 

Yes, but you don't got them! And these are impossible anyway.

Millions of people already have cars, and they know that new technology will permit them to keep cars. They are prepared to pay for them. The laws of economics say they will.

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Isn't the hydrogen economy a myth because of sheer expense?

 

...

 

Now, what if we simply rezone our cities around Transit Oriented Developments (TOD's) and designed cities that move people and goods, not cars?

 

I don't see the second as being cheaper than the first, especially in the US. Any solution that does not require large infrastructure changes is going to be preferred. Trains may be preferring parts of the world because the infrastructure is already in place, and autos/planes do not convey an advantage in time and/or convenience, but for the most part that's not the case in the US.

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To POM

 

As I have pointed out before, the transition will be slow and will take many decades. Sure, oil will peak soon. That simply means that it will go up in price, which will induce industry and individuals to make changes. That is one of the reasons that people will start to buy electric cars.

 

However, the oil will not run out overnight. It will take 30 to 60 years to become uneconomic, and I would think 60 is closer to the truth (because increasing oil prices will stimulate a massive exploration effort).

 

There will also be a big coal to liquid fuels move. Here in NZ we have enough lignite (low grade coal) to supply our vehicles with diesel for hundreds of years, and NZ is by no means unique in this. I mention this because the local newspaper mentioned that a government unit is currently quietly investigating that prospect. I do not agree with coal to liquid fuels, and see it as a backward move. However, I think it is (in the medium term) inevitable.

 

The point is that the move to alternative fuels does not have to occur, as you suggest, in 9 years. It probably has around 50 years, plus or minus a major error factor.

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It will take 30 to 60 years to become uneconomic, and I would think 60 is closer to the truth (because increasing oil prices will stimulate a massive exploration effort).

 

I would put that estimate at about 70+ years, but yeah, everything else in your post is pretty much spot on.

 

The point is that the move to alternative fuels does not have to occur, as you suggest, in 9 years. It probably has around 50 years, plus or minus a major error factor.

 

Better sooner rather then later, lest something unexpected comes about....

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Better sooner rather then later, lest something unexpected comes about....

 

This sooner rather than later line of thinking is often incorrect. Economic resources are limited. The money we spend now has to come from somewhere. Consuming our economic resources on today's poor solutions may mean that we have to limit research into tomorrow's better solutions.

 

So for example in the future you may have to retire. Should you save money for retirement in your early 20's? Perhaps spending that money on a college education would be a better idea. (Perhaps spending the money on girls and beer is a better idea in your early 20's.)

 

Here in the US you sometimes still hear the expression "if we can put a man on the moon, why can't we …" Well perhaps we can't do the thing they want since we spent all our money putting a man on the moon.

 

So if we have 60+ years to figure out energy issues, perhaps we should spend our money researching better solutions for future not implementing todays poorer solutions.

 

Personally, I think there are lots of smart people in our capitalistic society doing that right now. That’s the beauty of capitalism. People have the incentive to find solutions to problems because it will make them wealthy.

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I would imagine that the US has also planned for the eventuality in which no one wants to give them oil. At least a large portion of the "leave the Alaskan oil alone" isn't because of ecological concerns. And, of course, there's always the military solution :)

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Isn't that the military problem?

 

Not for the US :D

 

This ignores the fact that cities are constantly being rebuilt anyway, and all we have to do is REZONE them and let natural attrition and replacement and rebuilding fill in around them. "IF you zone it, they will come". An estimated 1.6 trillion dollars of infrastructure in the USA needs replacing and upgrading, and should be done with new technologies and new systems of technologies in mind.

Worldchanging's excellent "My other car is a bright green city" explains that of a cars Co2 emissions, only half comes from the tailpipe. It then explains how in 20 years we could have most of the population not needing cars in the first place. Bye bye traffic jams, stress, accidents, death, dismemberment, alienation, isolation, and hello a fitter population that knows each other better and FEELS safer and more human. Oh, and solves peak oil and climate change as well. ;-)

 

That does seem like a good idea. However, having a mostly car-free population could also have been done 20 years ago, or even farther back. But I doubt that you're going to get people back to waking. For myself, I'd be perfectly happy with public transport and a bit of walking/biking, so long as I'm not carrying too much. But others (eg my grandparents) would be quite unable to walk very far.

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This ignores the fact that cities are constantly being rebuilt anyway, and all we have to do is REZONE them and let natural attrition and replacement and rebuilding fill in around them. "IF you zone it, they will come". An estimated 1.6 trillion dollars of infrastructure in the USA needs replacing and upgrading, and should be done with new technologies and new systems of technologies in mind.

Worldchanging's excellent "My other car is a bright green city" explains that of a cars Co2 emissions, only half comes from the tailpipe. It then explains how in 20 years we could have most of the population not needing cars in the first place. Bye bye traffic jams, stress, accidents, death, dismemberment, alienation, isolation, and hello a fitter population that knows each other better and FEELS safer and more human. Oh, and solves peak oil and climate change as well. ;-)

 

No, it doesn't ignore that. The rebuilding is done in a more-or-less random fashion, and rezoning/rebuilding is a very site-specific endeavor. You'd have to seize property to do this (and there's precedent for doing so, but this would generally be much more valuable property). You're calling for "Big Dig" scale projects, and possibly larger, all over the place. All of this is in addition to the 1.6 trillion that the US needs to spend on infrastructure.

 

And I'm leery of these utopian predictions (Bye bye traffic jams, etc) since they never seem to have panned out in the past. There are always the unforeseen complications.

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Mate, governments are responsible for our city designs, not the marketplace. Isn't it time we demand that they design cities to a higher standard?

 

To the extent that this is true, the time constant for it is long, not short. But the marketplace does have an influence.

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Somehow I do not think that cars will ever go away anytime in the near or far future.

 

And, from my experience from playing SimCity 4 (I know it's probably not the best game to cite, but supposedly it can simulate city building and planning), rebuilding or restructuring infrastructure isn't quite as easy as just simply demolishing a couple of city blocks... Especially if it has been built in place for a long time.

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Iceland is already trialling hydrogen fuel cells in buses.

 

http://ec.europa.eu/research/energy/pdf/efchp_hydrogen16.pdf

 

Electric vehicles are old technology, and will take little to introduce. Hybrids are becoming more common.

I struggle to see why POM is so reluctant to accept that alternative personal motor vehicles will become part of society.

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To Peak Oil Man

 

No-one denies that oil will run out, and become commercially non viable. However, the timing is highly debatable. Lots of predictions have already been made, only to see the deadline pass with no crisis. Believe it or not, there is still a lot of the world yet unexplored for oil.

 

My home is a classic example. New Zealand has an enormous continental shelf - larger than the total of all the Middle East oil countries put together. Only the tiniest fraction has been drilled, and from that tiny fraction, substantial oil and gas has been discovered. Several drills have discovered substantial oil fields which have been capped, since at the time, it was uneconomic to extract that oil.

 

The whole of Antarctica remains unexplored, and geological surveys (without the drilling) have shown enormous potential for oil. Now, you might disapprove of such exploration, but you cannot deny the potential.

 

There is little doubt that very big oil fields remain to be discovered.

 

I am half way through reading the latest New Scientist. (Australian printed edition ; 1 March 2008) It has a couple of items that are of relevence.

 

Section on electric vehicles. I quote :

 

"The new roadster by Tesla Motors of San Carlos, California, is an all-electric sports car with a chassis based on the Lotus Elise. It boasts a 185 kilowatt engine powered by nearly 7000 finger sized lithium ion batteries packed into its trunk. This takes it from 0 to 100 kms per hour (63 mph) in about 5 seconds, and gives a top speed of 200 kms per hour. The range is a much more modest 350 kms - and then only if conservatively driven. Tesla hopes to sell 600 of the two seaters by the end of this year.

 

Unfortunately, the performance figures are not the only spectacular numbers associated with the Roadster. It costs a cool $100,000 and the battery pack is expected to need replacing after 3 to 5 years at a cost of $20,000."

 

This gives an idea of the technology level for electric cars. The cost will come down, and especially for lower performance runabouts.

 

The article goes on to describe a new lithium battery technology that will extend the life of the batteries ten-fold. Thus battery life will no longer be a significant limiting factor, or battery replacement a major added cost.

 

The other item is an article with the title "Let's Hear it for CO2."

It describes several methods under development for converting CO2 to CO using concentrated sunlight. The CO can then be reacted with H2 to form hydrocarbons - synthetic fuel with no net greenhouse impact. The suggestion is that these techniques are quite suitable for very large scale synthesis of fuel.

 

Maybe I won't have to trade in my car for a bicycle any time soon.

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What about a bicycle or a motorcycle? I get 50-55 mpg on my bike, and it'd probably be a lot easier to convert to alternative fuels.

 

As for bicycles, it depends on what you eat to get the calories to ride. I recall reading that driving is often more "efficient" than walking if your calories were supplied by steak -- the CO2 emissions from the production of the beef are greater than those from the gasoline in your car.

 

Hence why we need pint-sized cows in everyone's back yards to make things efficient.

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