[Bioconversion] combined cycles

[Mike Morin]

Paul Harris wrote:

>Nature is very good at
>sustainability until homo sapiens get involved and try to change the
>energy balance!

Mike Morin responds:

Nature is better at sustainability than man. Nature tends to form more 
mature communities in which resources are recycled within. The natural 
progression however tends to be towards and eventually past climax, but 
exhibiting cyclical patterns tending towards maturity.

We can learn much from the study of ecosystems in the way that we redesign 
and rebuild our communities. With respect to the very real and very alarming 
concerns related to "peak oil", other finite resources, and population 
concerns we need to recognize the need to live within our means and 
undertake the planned allocation of resources with the goal of building 
walkable communities wherever possible. The fossil fuel age has been about 
150 years, the automobile and the airplane have been with us for about 100. 
We need to recognize that these technologies are a relative flash in the 
pan, a super-nova of human history. The heating, cooking, electricity, 
fertilizer, and long(er) distance transportation of necessities that we 
value so much and take far too much for granted are tremendous opportunity 
costs relative to the terrible daily squandering from personal 
transportation use, the willy-nilly shipment of "goods", much of which is 
extraneous and mostly low quality, most often shipped long distances.We will 
realize terrible consequences in the next generation or so, if we do not 
move fast and rationally to adjust.

I think it's well past time (pun intended) to move beyond discussion of 
these matters and begin taking action.

Hopefully, we can pull together as a unified people and organize and 
mobilize the resources accordingly.


Workin' for peace and cooperation,

Mike Morin


----- Original Message ----- 
From: "Paul Harris" <paul.harris at adelaide.edu.au>
To: "Discussion of biological conversion to fuels and chemicals" 
<bioconversion at listserv.repp.org>
Sent: Wednesday, June 20, 2007 8:50 PM
Subject: Re: [Bioconversion] combined cycles


> G'day All,
>
> I have noted the comments on "political" posts, but part of the world's
> problem is that "problems" are often solved in isolation, with little
> knowledge/consideration of possible side effects. I hope I'm being
> realistic rather than political.
>
> Please excuse my sarcasm, but even at the "wonderful" 50% efficiency
> half the enegy going into the boiler is going up the chimney!
>
> I think it is time we changed or an energy economy and properly
> accounted for all the energy involved, as Joules are the same
> everywhere, cannot be devalued and cannot be made or destroyed.
> "Economics" only favours using fossil fuel to produce ethanol because
> the cost of extracting oil and coal (which in turn is subsidised by
> cheap fossil fuel prices) is valued so cheaply, as is human labour in
> many countries. I think it would be more efficient system wise to just
> use the fuel used to produce ethanol directly for transport (but that's
> not quite so much fun as farming/distilling).
>
> If we keep "extracting" carbon from the soil (in this case organic
> carbon by growing plants) the agricultural system will fail, and this
> carbon also ends up in the atmosphere! Nature is very good at
> sustainability until homo sapiens get involved and try to chnge the
> energy balance!
>
> HOOROO
>
> AJH wrote:
>>
>> On Tue, 19 Jun 2007 12:50:07 +0930, Paul Harris wrote:
>>
>> >Any conversion of energy is inefficient, so wastes our precious
>> >bioenergy - <snip>
>>
>> I agree but need this always be so?
>>
>> I think the first coal fired engines were about 1/4% conversion
>> efficiency but now direct fired coal gas turbines in combined cycle
>> are said to achieve over 50% conversion.
>>
> SNIP
>> >
>> >Gaseous fuels are best suited to stationary applications and any liquid
>> >fuel will be needed for "emergency" uses.
>>
>> Maybe but it's economics that will dictate.
>>
>> A few days ago I asked a question about the amount of remaining carbon
>> is digestate slurry after  an "economic" residence time in a biogas
>> digester. The reason I asked is because UK government has moved the
>> goalposts again and there seems to be more emphasis on digestion of
>> specially grown rawstock. Like you everyone involved seems to think
>> the "spent" slurry should be returned to land. I just wonder if there
>> is scope for working a pyrolysis gasification process in series with
>> it?
>>
>> AJH
>>
>> _______________________________________________
>> Bioconversion mailing list
>> Bioconversion at listserv.repp.org
>> http://listserv.repp.org/mailman/listinfo/bioconversion_listserv.repp.org
>
> -- 
> Mr. Paul Harris
> Room G8, Leske Building
> Faculty of Sciences,
> The  University of Adelaide, Roseworthy Campus, AUSTRALIA 5371
> Ph    : +61 8 8303 7880
> Fax   : +61 8 8303 7979
> mailto:paul.harris at adelaide.edu.au
> I now use "MailGuard" - if you do not get a reply please make contact
> again (by fax?)
> http://www.adelaide.edu.au/directory/paul.harris
> Member IOBB http://www.iobbnet.org/drupal/
>
> CRICOS Provider Number 00123M
> ----------------------------------------------------------- 
> This email message is intended only for the addressee(s)
> and contains information that may be confidential and/or
> copyright.  If you are not the intended recipient please
> notify the sender by reply email and immediately delete
> this email. Use, disclosure or reproduction of this email
> by anyone other than the intended recipient(s) is strictly
> prohibited. No representation is made that this email or
> any attachments are free of viruses. Virus scanning is
> recommended and is the responsibility of the recipient.
>
> _______________________________________________
> Bioconversion mailing list
> Bioconversion at listserv.repp.org
> http://listserv.repp.org/mailman/listinfo/bioconversion_listserv.repp.org
>