The Coming Climate Change

[Mariss Freimanis]

What's with the acronyms? What is CSP, a new dietary supplement, a new psychological syndrome or a new disease I should be concerned about?

Mariss

[Geof]

Originally Posted by xyzdonna .....A thought, CSP can be used to super heat water, is this not correct? At high temperatures you can more easily disassociate the water molecule. Maybe apply a little direct current to the process and viola, hydrogen and oxygen. To quote Bob Dylan, "I think it can be easy done".....

No, no matter what you or Bob think you cannot get around the laws of thermodynamics. I have come across the misconception you have here many times. In a chemical reaction you are dealing with two separate properties; the rate of the reaction and the energetics of the reaction. They are connected but only in the sense that a reaction which releases a lot of energy will often proceed very fast; this is why some reactions are explosive or burn very fast. But the amount of energy involved in a reaction is not dependent on how fast it proceeds.

When electrolysing water to generate hydrogen and oxygen the rate of this energetically unfavorable reaction can be influenced by the electrode design, temperature, solute composition. So you can produce hydrogen faster or slower but the amount of energy going into breaking the hydrogen-oxygen bond is the same. All the energy that is released when the hydrogen reacts with oxygen has to be put into the system in the first place just to get the hydrogen.

And it is actually worse than that because during the electrolysis some of the electrical energy supplied to the electrolysis cell is wasted as heat so for every 100 units of electrical energy in you get fewer than 100 units of chemical potential energy out in the hydrogen. Then when you utilize the hydrogen in a fuel cell you lose more of the energy as heat. There is no way around it. The full cycle from electrical energy used for the electrolysis back to electrical energy has an overall efficiency of 50% or less for the polymer fuel cells proposed for the 'hydrogen economy'. So half the energy is lost even before the compression, storage and transport of the hydrogen is taken into account.

[Geof]

Originally Posted by Mariss Freimanis What's with the acronyms? What is CSP, a new dietary supplement, a new psychological syndrome or a new disease I should be concerned about? Mariss

Concentrated Solar Power; aka focussing collectors. There is a setup in CA someplace that operates with a Stirling enegine and has an efficiency pretty close to 30%, I think. It was mentioned in a different thread some time ago.

[xyzdonna]

Originally Posted by Mariss Freimanis xyzdonna, I have hope you can be persuaded away from the dark side. You still have an open mind.:-) Most important principles of Nature: (1) There is no free lunch, or (2) You cannot break even; you're lucky if you come close. Nature is Las Vegas; you can't beat the house. You cannot "super-heat" this and "zap" it with that. The energy put in to break molecular bonds will always be more than what you get back when you burn it again and reform those bonds. Look up the Third Law of Thermodynamics. Mariss

Thanks Mariss,
Yes, I think I have an open mind.

Most important principles of Nature: (1) There is no free lunch, or (2) You cannot break even; you're lucky if you come close. Nature is Las Vegas; you can't beat the house. You cannot "super-heat" this and "zap" it with that. The energy put in to break molecular bonds will always be more than what you get back when you burn it again and reform those bonds.

I know this, it's not going to be 100% efficient. If we could get 15% conversion efficiency it might be worthwhile.

Look up the Third Law of Thermodynamics.

I'm afraid to, I think there might be calculus involved.
Donna

[xyzdonna]

Originally Posted by Geof No, no matter what you or Bob think you cannot get around the laws of thermodynamics. I have come across the misconception you have here many times. In a chemical reaction you are dealing with two separate properties; the rate of the reaction and the energetics of the reaction. They are connected but only in the sense that a reaction which releases a lot of energy will often proceed very fast; this is why some reactions are explosive or burn very fast. But the amount of energy involved in a reaction is not dependent on how fast it proceeds. When electrolysing water to generate hydrogen and oxygen the rate of this energetically unfavorable reaction can be influenced by the electrode design, temperature, solute composition. So you can produce hydrogen faster or slower but the amount of energy going into breaking the hydrogen-oxygen bond is the same. All the energy that is released when the hydrogen reacts with oxygen has to be put into the system in the first place just to get the hydrogen. And it is actually worse than that because during the electrolysis some of the electrical energy supplied to the electrolysis cell is wasted as heat so for every 100 units of electrical energy in you get fewer than 100 units of chemical potential energy out in the hydrogen. Then when you utilize the hydrogen in a fuel cell you lose more of the energy as heat. There is no way around it. The full cycle from electrical energy used for the electrolysis back to electrical energy has an overall efficiency of 50% or less for the polymer fuel cells proposed for the 'hydrogen economy'. So half the energy is lost even before the compression, storage and transport of the hydrogen is taken into account.

Hi Geof,
You paint a bleak picture indeed. Usually I'm just trying to get around the speeding laws, these thermodynamic laws I'm a little hazy on.

So you can produce hydrogen faster or slower but the amount of energy going into breaking the hydrogen-oxygen bond is the same. All the energy that is released when the hydrogen reacts with oxygen has to be put into the system in the first place just to get the hydrogen.

OK, but use what Mariss said, about a 50% efficiency. Wouldn't this work? It is after all a method of storing energy. I realize you're going to lose some in the translation, but it is a method of storing energy for use vehicles.
Donna

[307startup]

Originally Posted by xyzdonna Hi Geof, You paint a bleak picture indeed. Usually I'm just trying to get around the speeding laws, these thermodynamic laws I'm a little hazy on. So you can produce hydrogen faster or slower but the amount of energy going into breaking the hydrogen-oxygen bond is the same. All the energy that is released when the hydrogen reacts with oxygen has to be put into the system in the first place just to get the hydrogen. OK, but use what Mariss said, about a 50% efficiency. Wouldn't this work? It is after all a method of storing energy. I realize you're going to lose some in the translation, but it is a method of storing energy for use vehicles. Donna

xyzDonna...

even if you use carbon-fiber pressurized tanks to avoid the problems with hydrogen embrittlement, you still have the pesky problem of how to avoid any ruptures in event of an accident...and then there's the volatility of the fuel to be considered. Care to see 10,000 mini-Hindenbergs every day??? That's the average number of car crashes in this country. I'm good on driving a ticking time-bomb thanks...

[xyzdonna]

Originally Posted by WYLD xyzDonna... even if you use carbon-fiber pressurized tanks to avoid the problems with hydrogen embrittlement, you still have the pesky problem of how to avoid any ruptures in event of an accident...and then there's the volatility of the fuel to be considered. Care to see 10,000 mini-Hindenbergs every day??? That's the average number of car crashes in this country. I'm good on driving a ticking time-bomb thanks...

Hi WYLD,
Good point, you're gonna have a rupture in the event of an accident. Yes, hydrogen is probably the most volatile fuel, very low molecular weight. That also means it will go up in the air very quickly and dissipate. Unlike gasoline which will linger around and burn everything up.
Donna

[307startup]

Originally Posted by xyzdonna Hi WYLD, Good point, you're gonna have a rupture in the event of an accident. Yes, hydrogen is probably the most volatile fuel, very low molecular weight. That also means it will go up in the air very quickly and dissipate. Unlike gasoline which will linger around and burn everything up. Donna

uh...how many cars in accident have you seen that just burst into flames and burn up? The problem with hydrogen is that the flash point is insanely low. Too little humidity will cause static discharge...kaboom! And when the hydrogen is escaping at 5000 psi or higher...do you really want to be in its path? I'm thinking not...

[Geof]

Originally Posted by xyzdonna .... It is after all a method of storing energy. I realize you're going to lose some in the translation, but it is a method of storing energy for use vehicles. Donna

When all the losses are taken into account and the complexity of hydrogen storage and refuelling and all the myriad details, coupled with the awesome cost of fuel cells it works out to be pointless. Have a look at Wikipedia on the topic of polymer fuel cells and you will see a company called Ballard Energy Systems mentioned. Then go onto some of the stock market websites and start looking up Ballard Energy Systems. They have blown umpteen millions of dollars on developing polymer fuel cells suitable for automobile applications...and failed.

[xyzdonna]

Here is some food for thought.

According to the U.S. Department of Energy, corn-based ethanol provides 26 percent more energy than is required for its production, while cellulosic provides 80 percent more energy. And while conventional ethanol reduces greenhouse-gas emissions 10 to 20 percent below gasoline levels, the reductions with cellulosic range from 80 percent below gasoline to completely CO2 neutral.
http://grist.org/news/maindish/2006/12/04/montenegro/

Switchgrass -- A perennial prairie grass native to North America, switchgrass requires little water or fertilizer to grow and thrives in places unsuitable for most crops, ranging from the Gulf of Mexico to Canada and from the Atlantic to the Pacific. Some five to nine feet tall, this gangly weed also yields twice as much ethanol per acre as does corn.

That said, researchers at the University of Minnesota and St. Olaf College recently found that biodiesel production is highly efficient, generating 93 percent more energy than is required to make it.

Enough biodiesel to replace all petroleum transportation fuels could be grown in 15,000 square miles, or roughly 12.5 percent of the area of the Sonora desert (note for clarification - I am not advocating putting 15,000 square miles of algae ponds in the Sonora desert. This hypothetical example is used strictly for the purpose of showing the scale of land required). That 15,000 square miles works out to roughly 9.5 million acres - far less than the 450 million acres currently used for crop farming in the US, and the over 500 million acres used as grazing land for farm animals.
http://www.unh.edu/p2/biodiesel/article_alge.html

The above article is an excellent treatise on biodiesel from algae. This is doable, cost effective and probably the way to go. The scale of land required would also be much less than from ethanol. The land could be desert land that is not currently used in food production.
Donna
PS: It does assume a reduction in fuel usage through the use of hybrid diesel engines, but that has to be taken as a given.

[Mariss Freimanis]

Land that is presently desert is desert because there is no water. Where pray tell would the water come from to grow these wonderful plants? The only river of significance here in the Southwest is the Colorado. Its water is already used to 100% capacity.

Mariss

[Geof]

Donna; Regarding "Here is some food for thought." I am disappointed, you are cherry picking. I pulled down the Montegnegro article, started reading and thought I might pull out a few of the inconsistencies and assumptions.

The list was getting a bit long but then I came across this:

Incidentally in the context of your "This is doable, cost effective and probably the way to go. comment on bio-diesel from algae take notice of the first two sentences in what I copy below. Also in the case of the algae source never mind economic feasibility it has not been done on anything other than a research scale and it is very difficult to scale this type of thing up.

Making biodiesel from algae is analogous to making ethanol from cellulose. Both technologies hold great promise but neither has been proven economically feasible.

The following two sentences sound contradictory:


Over its lifetime, pure biodiesel emits about 78 percent less CO2 than conventional diesel ... They also found that biodiesel reduces greenhouse-gas emissions by 41 percent compared with fossil fuels.
Also note that this is for soy biodiesel. Palm oil biodiesel is far more CO2 neutral but about 100% more destructive of biodiversity, which makes it worse from a global warming perspective because further production of palm oil will require destroying remaining carbon sinks (the destruction of which presently accounts for about 20% of all global warming).


When Tier 2 emissions standards bring biodiesel up to par with gasoline and ethanol for air pollutants, biodiesel seems like it should be a no-brainer for green energy.
Note also that these standards will bring cars that burn regular diesel up to par with gasoline cars. In other words, one of the biggest reasons to use biodiesel (less pollution) will be mooted. That will leave energy independence and reduced CO2 as the remaining arguments. But, since we can only replace half of a percent of our diesel (as you point out) the energy independence argument is a farce and should be tossed. That leaves one argument for its use. It produces less CO2. But, is that 78% less or 41%? But again, because we can replace less than half of a percent of our diesel use, we can only reduce our CO2 production by half of that, making CO2 reduction about a quarter of one percent. These numbers make the CO2 argument rather farcical as well since we will leave 99.75% of our CO2 production from diesel untouched by using soy biodiesel.

I have never used the word farcical but it is appropriate.