[Digestion] Digestion Digest, Vol 19, Issue 16

Wed Jan 30 18:17:26 CST 2008

Dear Mr. Kasulla,
CNG is a fossil fuel and therefore its use adds to the net carbon dioxide of
the atmosphere. This is the main reason why it should not be used. When we
use biogenous methane as fuel, we are using a carbon neutral fuel. Secondly,
one can tune the engine properly to burn the methane. It is much easier than
using nuclear power to run buses and automobiles.
Yours
A.D.Karve
----- Original Message -----
From: Srinivas Kasulla <srinivaskasulla at gmail.com>
To: <digestion at listserv.repp.org>
Sent: Wednesday, January 30, 2008 12:48 AM
Subject: Re: [Digestion] Digestion Digest, Vol 19, Issue 16


> GAS POWERED BUSES A CLIMATE THREAT..............IS IT TRUEEE ?????
>
> Gas powered buses are often launched as a cheaper alternative to
> trolleybuses. However, they emit substances that are more harmful to
> the climate than even diesel buses.
>
> The world politicians efforts on combatting global warming is
> concentrating on reducing carbon dioxide (CO2) emissions.
>
> But is that really so important compared to methane (CH4)?
>
> The 'relative greenhouse effect' of methane is estimated at about 17
> times that of carbon dioxide. But it is true that the emissions of
> carbon dioxide still are much greater than those of methane. So the
> 'historic' global warming effect that we have seen might be caused
> largely by carbon dioxide.
>
> However, the emissions of methane are increasing on a much faster rate
> than those of carbon dioxide. It is no doubt that global warming in
> the future more and more will be associated with methane.
>
> In addition, the use of methane-containing fuels is even advocated by
> environmental interests. The methane in the atmosphere come from a
> variety of sources, among those most important are agriculture,
> garbage dump sites, exploration of natural gas fields, pipelines for
> natural gas, leakages from gas depots or gas filling stations,
> emissions from end use of natural gas or biogas in household, industry
> or vehicles.
>
> The fact is that natural gas as well as 'biogas' contain 95-98%
> methane. Environmental organisations use to promote the use of
> 'biogas' as an alternative to fossil fuels. However, the CH4 emissions
> must be taken into consideration. 'Biogas' is often produced from
> garbage or harvested grass that is anaerobically treated. If not
> biogas was produced, some methane would anyhow be produced from the
> dump site but the majority of the coal-containing compounds would be
> transformed into other hydrocarbons or just carbon with time. So there
> is a considerable net emission of methane (and also carbon dioxide) if
> biogas is produced and used in vehicles. Still worse is of course the
> use of natural gas in buses.
>
> The use of natural gas - or biogas - in buses is usually associated
> with significant emissions of methane due to that engines are tuned in
> to reduce emissions of nitrogen oxides which otherwise would be a
> problem for gas-powered vehicles. This is especially true for cold
> starts and during city traffic conditions.
>
> A Swedish study assesses the greenhouse effect of methane emissions
> from biogas-powered vehicles to about 3 times the greenhouse effect of
> carbon dioxide emissions from diesel-powered vehicles. Even if
> considered the shorter average life of methane emissions compared to
> CO2, the greenhouse impact from biogas buses seem to be far higher
> than the greenhouse impact of diesel buses. Natural gas powered buses
> are still worse since they also emit fossil CO2. More to read in
>
http://the-greenhouse-effect.blogspot.com/2006/06/is-methane-big-danger.html
>
> This is thus a contradiction - that environmental organisations call
> for the use of gas-powered vehicles when methane emissions might
> become the most significant global warming problem in the future.
>
> If we cannot control the methane buildup in the atmosphere there might
> be more severe effects as methane is released from 'frozen' deposits
> at sea bottom when the water warms up. The resulting greenhouse effect
> might be much worse than what we are now discussing - there might be
> an increase in global temperatures of 20-30 degrees C which in fact
> has happened historically, last time during Eocene period som 55
> million years ago when the North Pole had a climate with temperatures
> about +20 degrees C and of course no ice.
>
> So try to stop the methane emissions before it is too late. Use cheap
> power from nuclear energy instead of natural gas or biogas wherever
> feasible. Use electric trolley buses in cities with zero emissions
> instead of experimenting with gas-powered buses.
>
> was just wanted to rectify whether this news is true or not.
>
> with regards
> srinivas kasulla
> Mumbai9869179601
>
> On 1/29/08, digestion-request at listserv.repp.org
> <digestion-request at listserv.repp.org> wrote:
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> > Today's Topics:
> >
> >    1. Re: Solid Waste (francois chartier)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Tue, 29 Jan 2008 00:35:12 -0800 (PST)
> > From: francois chartier <francoischartier at yahoo.com>
> > Subject: Re: [Digestion] Solid Waste
> > To: digestion at listserv.repp.org
> > Message-ID: <731715.50193.qm at web50406.mail.re2.yahoo.com>
> > Content-Type: text/plain; charset=iso-8859-1
> >
> > Hi all,
> >
> > As anyone experience in biogaz using solid waste? What
> > type of digester, handling, etc.
> > cheers
> > Francois
> >
> >
> >
> >
> >
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> > End of Digestion Digest, Vol 19, Issue 16
> > *****************************************
> >
>
>
> --
> SRINIVAS KASULLA
> M E D C/ M E S N
> 09869179601
>
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> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> http://info.bioenergylists.org