RE: Biomass co-firing certification

["OConor.Richard" <Richard.OConor@minergy.com>]

Title: RE: Biomass co-firing certification

Hi, A few weeks ago, somebody posted an article regarding the limited availablity of natural gas in the U.S.  Does anyone have a copy of this article or any suggestions where I can find it?

-----Original Message-----
From: Weststeijn, Andries [mailto:Andries.Weststeijn@essent.nl]
Sent: Friday, October 25, 2002 10:15 AM
To: 'JBenemann@aol.com'; fbeck@repp.org
Cc: bioenergy@crest.org; FMurrl@aol.com
Subject: RE: Biomass co-firing certification

Dear Mr. Benemann, Mr. Beck,

On gasification and cofiring: has it been tried and how does it compare?

Yes, we do gasify (in Holland). At a reasonable scale . And there are
others, like the Lathi plant in Finland and the McNeil power station in
Burlington, Vermont (the FERCO/Battelle process).
These are currently perhaps the 3 best examples of cofiring of pre-gasified
biomass in a utility scale classic boiler.

At our company we have a 80 MWth CFB gasifier built by Lurgi/Germany feeding
a 700 MWe pulverized coal plant; gasifier capacity 150.000 tons/year of dry
waste wood. Unfortunately no gasifier info on our web site.
We cofire several types of biomass directly with coal (mixed either in the
coal yard and/or in the pulverizers).
We actively look at CFB combustion with steam-integration with the main
plant's turbines.
We actively look at a variety of pre-prep methods to increase the
weight/energy percentages for direct cofiring, while mixing upstream or
downstream of the pulverizers.

Generally, we work towards substitution of 20% of coal by biomass (i.e. 20%
on energy-basis). That's double that on fuel weight-basis and even more so
on a fuel volume-basis.

There is (and most likely will remain to be) a market for all methods,
including gasifying.
The optimal concept for cofiring indeed depends on many variables, including
biofuels type and supply, plant emission limits and ash re-use or disposal,
payback time horizon, national green power policies.

Gasifying and "separately feeding into the boiler" are examples of process
installations requiring substantial front-end investments (and also
continuous maintenance). Direct cofiring with coal requires hardly any if at
all.
Within that range a lot of options are open (with an equal large range of
complexities if one so desires).

It is almost a classic engineering case: weighing technical options against
economics.
In this case spiced up by green policy: can one rely for any length of time
on "green" financial incentives.

Personally, I expect biomass cofiring to tend to be done in state-of-the-art
coal plants rather than in outdated coal plants. The large efficiency
differential will favor use of modern plants, since clean biomass is -after
all- on the average a more expensive fuel than coal (I am not talking about
wastes here).
In Europe, the goal for the new boiler-type coal plants is 54% efficiency
(on coal), becoming available from approx 2015 onwards. Including a clear
design objective of cofiring biomass.
Replace 20% of the coal in those new plants by biomass and you knock off
almost half of the CO2 emission per kWh related to coal, when compared with
the current average coal plant efficiency of 36%.

Perhaps old plants might benefit for a limited number of years by wrangling
out some life extension by not having to add flue gas filtering for the
remaining years. But these will licensing related cases, varying greatly
from region to region around the world.

A sensible way of combining ultra high boiler efficiencies with coal
substitution has a lot of potential to contribute to sustainable power, say,
in the coming 50 years. The next generation of coal plants is simply not yet
going to be replaced by wind and PV (and not even by natl gas and/or
nuclear).
The alternate power generating options will simply not be available at the
required scale, worldwide, in the period, say, 2020-2060 to fully replace
the enormous current generating capacity on coal.

It may sound like I am making a pitch for coal here. Rather, I want to make
the point on this Bioenergy List that there still will be a next generation
of coal plants, by sheer lack of timely available large scale alternatives.
Whether this is considered desirable or not...
Therefore, all efforts currently invested in biomass cofiring in coal plants
are -in my view- both wise and necessary in order to reap the (green)
benefits not only now, but also during that next generation of coal plants
to come.

After that...(i.e. after the middle of this century).. it is anybody's guess
what new (alternate) power generation systems will have scaled up
sufficiently by then to really push coal way down from its current capacity.

 
best regards,
Andries Weststeijn
Essent/Netherlands
 

-----Original Message-----
From: JBenemann@aol.com [mailto:JBenemann@aol.com]
Sent: Friday, October 25, 2002 12:56 AM
To: FMurrl@aol.com
Cc: bioenergy@crest.org
Subject: Re: Biomass co-firing certification

Dear Mr. Murrell:

Re. your e.mail to Mr. Beck, I strongly agree with you that a good way to
introduce biomass into coal-fired power plant  would be a biomass gasifier,
for the reasons you state.  Of course, this is a matter of specifics at the
power plant, etc.  But in many cases is it just too difficult to mix biomass

with coal and it is better to feed them separately into the boiler.   Are
you
aware of any such system having ever been tried?  Maybe time to do that. 

Sincerely,

John R. Benemann, Ph.D.
3434 Tice Creek Dr. No.1
Walnut Creek, CA 94595
(925) 939 5864 Fax (925) 944 1205
Cell (925) 352 3352  jbenemann@aol.com

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