[Digestion] Biogas + CCS = highly feasible qua N input

Wed Sep 12 21:24:40 EDT 2007

Good question: 230 square miles = 60,000 hectares.

 -you need at least 75 kilograms of nitrogen fertilizer per hectare for a good cassava crop = 4500 tons for 60,000 ha

 -it takes around 33,000 cubic feet or 930 cubic meters of natural gas to make 1 ton of N fertilizer (i.e. 148,500,000 cubic feet or 4,205,000 cubic meters of natural gas for 4500 tons)

 -thus, we would spend 4,205,000 cubic meters on natural gas to obtain 300,000,000 cubic meters of natural gas equivalent biomethane from cassava.

 -in short, the final balance is extremely positive, we only need a tiny bit of NG inputs to get a huge amount out

I bet that for sugar cane the balance is even better.

"Scupham, Samuel K." <ScuphamSK at bv.com> wrote: You'll have to check my units, but I did some quick math to put in perspective how much energy this is, just throwing some round numbers at it.

21000  Btu/lb NG
250000 tons NG/tanker
500000000 lbs NG/tanker
1.05E+13 Btu/tanker
6900  Btu/kWh for 2x1 combined cycle
1521739130 kWh/tanker
500000 kW output for 2x1 combined cycle
3043  hours of 500 MW combined operation per tanker

How much natural gas do we need to fertilizer 230 square miles of cassava?

Regards,
Sam Scupham

-----Original Message-----
From: digestion-bounces at listserv.repp.org [mailto:digestion-bounces at listserv.repp.org] On Behalf Of Lou Dobb
Sent: Tuesday, September 11, 2007 6:22 PM
To: Scupham, Samuel K.; Duncan Martin; Digestion at listserv.repp.org
Subject: Re: [Digestion] Biogas + CCS

The friends over at Biopact have already done so.
 Quote:
 ===
 To fill the largest LNG tanker currently on the market - with a capacity of 250,000 tons of liquefied natural gas, equivalent to around 300 million cubic meters of natural gas - with pure biomethane, one would need between 450 and 650 million cubic meters of biogas. This amount can be obtained from around 60,000 hectares of cassava, or 40,000 hectares of sugarcane.
 ===

 Say you capture the carbon dioxide from those 650 million cubic meters of biogas (at 35% CO2 per cubic meter), you would get around 450,000 tonnes of CO2.

 Most current sequestration projects pump between 5 and 10 million tonnes of CO2 per year into wells (e.g. Statoil = 10mio t/y).

 Now clearly, we only generate 450,000 tonnes of CO2 per LNG tanker we fill with biomethane, which allows for great flexibility; either we stick to 1 shipment per year because we have chosen to sequester into a tiny site; or we simply create a larger plantation because we have chosen to sequester into a larger site.

 Of course, much more flexibility is possible because of the emergence of CNG ships. These don't require liquefaction/regasification infrastructures and would be an excellent match for biogas + CCS projects.

 On oceanic CNG transport and tankers, see here:
                          A quick look at CNG ships       
 http://biopact.com/2007/09/quick-look-at-cng-ships.html

 Not sure, but it could be feasible, couldn't it? Just think of the fact that we can actually go carbon-negative! All other renewables and nuclear are merely carbon-positive or carbon-neutral. That is: they prevent new emissions from entering the atmosphere. Biogas + CCS would take emissions *from the past* out of the atmosphere.

 Mmm, not sure.

 Cheers, Lou

"Scupham, Samuel K."  wrote: It would be an interesting exercise to calculate how many acres of crops would need to be digested to produce enough methane to fill an LNG tanker. 

Regards,
Sam Scupham

-----Original Message-----
From: digestion-bounces at listserv.repp.org [mailto:digestion-bounces at listserv.repp.org] On Behalf Of Lou Dobb
Sent: Tuesday, September 11, 2007 2:47 PM
To: Duncan Martin; Digestion at listserv.repp.org
Subject: [Digestion] Biogas + CCS

Duncan, I think you have misunderstood the idea of so-called "Bio-energy with Carbon Storage" systems (BECS).

The entire point is to build your biogas plant at the sequestration site. The great advantage of biogas production is that you can clean up the gas at the sequestration point before you burn it (pre-combustion carbon capture). This means you become entirely independent of power plants; no need for power plants, no need for nearby markets. You grow energy crops for biogas close to the sequestration point; this can be any remote point.

Scientists have said that such BECS systems are the most feasible way to combat climate change; they can take us back to pre-industrial atmospheric CO2 levels by mid-century. They studied these systems in the context of "abrupt climate change" scenarios and geo-engineering options.

So to illustrate the concept: take a depleted near-shore oil well in Angola: on-shore you grow crops; digest them, scrub out the CO2 and pump it into the old oil field. Then you have ultra-clean, carbon-negative biomethane, that can be exported (either in CNG ships or in LNG tankers).

This concept precisely allows you to use sequestration sites that could otherwise not be used. That's a huge advantage. Other CCS concepts have the great disadvantage that they are tied to power-plants, and so they must find a sequestration site close to an already existing power plant; this often requires huge and costly infrastructures.

By building your biogas plant right on the spot of the sequestration site, you avoid this.

There's some interesting research showing that there are a large number of such remote sequestration sites.

Finally, the economics might work out given the fact that carbon prices are set to skyrocket.  Moreover, if you want to sell NG quality gas, you have to capture carbon anyways. So why do all this effort to then release it into the atmosphere, when you can just as well store the captured CO2 in a sequestration site?

I found an interesting article about this concept, here:
     Pre-combustion CO2 capture from biogas - the way forward?http://biopact.com/2007/03/way-forward-pre-combustion-co2-capture.html

It seems like biogas with CCS could be a winner because carbon capture costs are considerably lower than for fossil fuels (check the table).

Yours, Lou

Duncan Martin  wrote: Lou and all

The principle of sequestration is fine - but I very much doubt that the 
economics would work for AD.

You have obviously grasped one of the major problems, that of scale, when 
you suggest locating the biogas plant near a carbon sequestration site 
(which would certainly have to be near a major source, such as a large power 
plant or a large sink, such as an oilfield). Such installations are not 
generally in the same areas as anaerobic digesters.

 The energy used to haul the digester feedstock to the biogas plant and to 
haul the digestate back to wherever it is to be used would add substantially 
to the operating costs of the biogas plant, the economics of which are 
generally fairly marginal at best.

 At the scale of many biogas plants, a more realistic option might be to 
supply it to glasshouses, where it would be sequestered by boosting plant 
growth. At least one Scotch whisky distillery was doing this 30 years ago, 
although the CO2 came from the fermentation process, not from a biogas 
plant.

(The Scots might be a more cheerful race, if it were not for the fact that 
only 50% of the carbohydrate that goes into a distillery comes out as 
ethanol!! The remainder, of course, is lost as CO2. However, they can 
console themselves with a per capita production rate of ethanol about 10x 
higher than their nearest competitor! 20x would be nice, of course - but why 
be greedy?)

An interesting alternative might be to release it in an unconfined growing 
environment, such as a biomass plantation or forest. I do not know how 
efficient the capture of CO2 would be but my guess would be that a dense 
plantation or forest canopy might extract quite a lot of the CO2, at least 
in summer, provided it was released at ground level and well away from the 
edges of the planted area. An efficiency well below 100% would still make a 
useful contribution, given that the energy cost and transport costs would be 
almost zero.

Otherwise, I do not think there is usually much alternative to venting the 
CO2 to atmosphere. It might be argued that this is equally good, since it 
will sooner or later be taken up by plant growth anyway. It follows that the 
above 'forest' proposal would only be useful if there was a significant 
improvement in the biomass growth rate -- which there might be.

Duncan J Martin

Chair
Republic of Ireland Centre
Chartered Institution of Wastes Management

================================
CONTACT DETAILS
Duncan J Martin, PhD, CEng, CSci, MIEI, MCIWM, MIChemE
24 Townsfield, Cloughjordan, N Tipperary, Ireland
Mobile: +353 86 8377 906
Home: +353 505 42087
Email: duncanjmartin at eircom.net
================================

----- Original Message ----- 
From: "Lou Dobb" 
To: 
Sent: Tuesday, September 11, 2007 6:14 PM
Subject: [Digestion] What happens to CO2 when scrubbed out of biogas?

Okay, I'm a bit of a lay man, but I wonder what happens to the CO2 if it is 
scrubbed out of biogas by water washing.

And, importantly, wouldn't it be possible to store this CO2 underground (as 
in carbon capture and storage systems; in depleted oil fields)? This would 
make biogas carbon-negative.

In principle you could make ultra-clean biogas near a carbon sequestration 
site (independently of power plants), store the carbon there, and export the 
carbon-negative biomethane which is now upgraded to natural gas quality.

You would get a premium for this carbon-negative gas (carbon currently costs 
ï¿½,ï¿½20 per ton, but this is expected to increase significantly).

So has anyone thought about coupling biogas production to CCS?

---------------------------------
Be a better Globetrotter. Get better travel answers from someone who knows.
Yahoo! Answers - Check it out.
_______________________________________________
Digestion mailing list
Digestion at listserv.repp.org
http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
Beginner's Guide to Biogas
http://www.adelaide.edu.au/biogas/
http://info.bioenergylists.org

-- 
Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.5.485 / Virus Database: 269.13.3/986 - Release Date: 03/09/2007 
09:31

---------------------------------
Yahoo! oneSearch: Finally,  mobile search that gives answers, not web links. 
_______________________________________________
Digestion mailing list
Digestion at listserv.repp.org
http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
Beginner's Guide to Biogas
http://www.adelaide.edu.au/biogas/
http://info.bioenergylists.org

---------------------------------
Don't let your dream ride pass you by.    Make it a reality with Yahoo! Autos. 
_______________________________________________
Digestion mailing list
Digestion at listserv.repp.org
http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
Beginner's Guide to Biogas
http://www.adelaide.edu.au/biogas/
http://info.bioenergylists.org

---------------------------------
Shape Yahoo! in your own image.  Join our Network Research Panel today!