Hans Erren responded, “Still, IMHO a diesel based infrastructure for transport will live a long life, in particular in remote areas, as it is low tech.”

A couple comments:

1) I knew that batteries had a much lower energy density (energy per unit mass) than diesel fuel, but I didn’t realize quite how much lower. Wonderful Wikipedia (;-)) has good information on the difference:

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

hydrogen: 120 MJ/kg
diesel: 63.47 MJ/kg
lithium ion battery: 0.54 to 0.72 MJ/kg

However, it should be noted that the diesel and the hydrogen have to be put in a container, which adds additional mass (though not much for a diesel gas tank). And even more important, they both have to go through an engine/transmission (or with hydrogen, it could be a fuel cell) to change the energy form into something more usable, whereas the electricity in a battery goes through an electric motor to drive the wheels.

Further, the cost advantage for batteries that get their energy from central generation is currently pretty large. For example, if a diesel car gets 30 mpg, at $3/gallon (just to use some easy numbers), that works out to 10 cents/mile. Whereas, at 9 cents per kilowatt-hour, I’ve read that the cost per mile for electricity from the grid (assuming appropriate battery charging efficiencies and electric motor efficiencies) is about 3 cents per mile.

2) Diesels are becoming amazingly clean (particulate-wise, anyway) as very-low-sulfur diesel fuel is starting to come on the markets in all developed countries, and as particulate filters are beginning to be very common in developed countries.

3) However, the long term trend seems very clear to me. All forms of internal combustion engine will eventually be replaced by completely electrified cars…which could very well involve cars having fuel cells. That’s what I was commenting on, Hans…your mention of the year 2100. I don’t see diesels surviving to 2100 (not that anyone can realistically see anything in 2100!).

4) Regarding diesels’ lifetime: I’m working on project that looks at international transportation regulations. One thing that has struck me is that the world is rapidly becoming much more unified in its transportation regulations. I’m thinking of developing countries like China and India. Their regulations are at most a decade behind those in Europe and the United States. And they are catching up, rather than falling further behind. I think that will work against internal combustion engines, even in countries like China and India. If fuel cell vehicles begin to displace significantly displace hybrids circa 2020-2030 in the most advanced countries, I don’t see more than 1-2 decade delay for equal market penetration in China and India.

5) Soo…I see the last diesel (or gasoline) automobile engine rolling off an assembly line before 2050.

Still, IMHO a diesel based infrastructure for transport will live a long life, in particular in remote areas, as it is low tech.

Time will tell.

Here’s a link to “Twenty Hydrogen Myth’s”, also from the above Rocky Mountain Institute (RMI) website referenced above
http://www.rmi.org/sitepages/pid171.php#20H2Myths

This adresses the hydrogen saftey issue, along with lots of other issues related to hydrogen.

**Blog topics, even MORE than traditional news topics, seem to have an exceedingly short shelf-life, making me wonder a little about the value of posting to one, particularly on an “outdated” (a few days old) topic like this one. To be honest, I just recently started posting on this blog, and my judgement on its value is still not in. I’m still trying to figure out if it indeed HAS value. The problem is that, while there may be useful information somewhere here, it might be more readily accessed elsewhere (with a simple search) without having to wade through all the opinion (some of which, I admit I have expressed).

The hydrogen saftey issue is obviously very important, but IF this issue could be properly addressed, hydrogen would undoubtedly trump both diesel and batteries as an energy storage solution.

The following link addresses the safety issue (along with a lot of other stuff about a hydrogen economy on the site http://www.rmi.org/)

http://www.rmi.org/sitepages/pid536.php

Particulalry relevant is the authors’ statement that “hydrogen can be safer than gasoline if it is used properly”. They explain why, in a very straightforward manner.

Yes, diesel presently delivers more energy per kilogram than batteries. But the energy per kilogram of batteries is increasing significantly (and charging time is decreasing significantly), due to nanotechnology:

http://www.evworld.com/view.cfm?section=commu&newsid=10734

http://www.technologyreview.com/read_article.aspx?id=16624&ch=biztech

A 200-250 mile range is good enough for me. And that 3-minute charging time…pretty impressive!

As for J/kg diesel still outweighs batteries, and it’s far safer to handle than hydrogen.

As byproduct you also have a CO2 sequestering programme. You could store the diesel in oilfields.

Please forgive me.

Also, Kooito’s point about “theoretical limits” is well taken.

Actually, there are TWO “theoretical limit” issues involved here. One is the theoretical MINIMUM energy required by the capture system to capture a ton of carbon (in CO2) (which is system dependent, of course, but is given as ~4 GJ/tC by Keith, presumably for the Sodium hydroxide system that he has proposed).

The other is the “carbon-specific energy content” of fossil fuel: 40, 50, and 70 GJ/tC for coal, oil and natural gas, resp (given by Keith).

From the numbers I have found elswhere, these would appear to be primary energy contents (ie, max numbers for available energy provided). Eg, Keith’s 70 Gj/tC is consistent with a 14.92 carbon coefficient factor (Metric ton carbon per quadrillion BTU) — equivalent to about 67 Gj/tC — that I found elsewhere http://www.eia.doe.gov/oiaf/1605/87-92rpt/chap2.html

If one used electricity produced at a central generating station to power the capture system (compressor and fan), for example, the USABLE energy delivered by fossil fuel (to power the capture system) per ton of carbon produced would have to be reduced significantly from the 40, 50, and 70 GJ/tC numbers provided by Keith (bringing them closer — in some cases MUCH closer to the 4 GJ/tC MINIMUM need for capture).

For example, if one used coal to produce ELECTRICITY at a central station and assumed about a 15% overall efficiency, one would already be very near to the “break even point” — ie, only about 6 GJ/tC would be provided, while at least 4 GJ/tC are required, according to keith.

If one assumed worse than the best case minimum energy required for capture (eg, assume that 7GJ/tC required for capture instead of 4GJ/tC), then it would not even make sense to do the capture at all using electricity provided by a central coal-powered electical generating station, since more carbon would be released in powering the system than was captured.

Of course, there is nothing saying that the compressor and fan could not be powered DIRECTLY ON SITE(by natural gas, for example), which would certainly be a better scenario than the centralized electrical power one from an overall efficiency standpoint, though even this would require reducing the 40, 50, and 70 GJ/tC numbers provided by Keith, of course.

I assume that Keith must have made some adjustments in his COST estimate calculations to take the above efficiency issues into account, but I must admit I do not know if that is the case.

I think that the overall viability of this kind of technology crucially depends on certainty of CO2 sequestration. I doubt that there can be places where compressed CO2 will certainly be stable for millenia. I admit a relative merit of air capture over power plant exhaust capture that the capture plant can be located at best places in this respect. But it is just relative.

If sequestration is certain, the idea using biomass seems to work. But as usual in schemes employing biomass energy, its requirement of land competes with food production and nature conservation.

I guess that it is difficult to achieve high energy efficiency in chemical cycle processes involving CaO and/or NaOH to capture CO2. But this is just a guess and it seems worthwhile to make technology assessment if (but only if) there is outlook of sure sequestration.

By the way, it seems strange to me (a climatologist) that the authors assume that future people will certainly be wealthier than us (unless either the abatement cost or the damage related to climate change be too high). I think this is just a wishful thinking that we should not depend on (though we should not exclude that possibility either).

While it appears that Keith is giving two different values in the quote above, this is NOT the case.

It actually appears as “4″ in both places in the original pdf document.

The “.4″ posted above (in the line “The .4 GJ/tC minimum may be compared to the carbon-specific energy content”)

should ACTUALLY read “~4″ (ie, about 4)

The “~” got transposed to “.” when I copied the text from the pdf document.
I did not notice this until after I posted it. Sorry.