A preliminary analysis of CO2 emissions

And conversion to fertilizer and hydrogen

for

coal fired Power Plant application

  Example Power Company

GIVEN:                       100 million tons of carbon dioxide released annually from a set of 60 fossil fuel power plants.

Target reduction             13.7 million tons or 3.7 million tons of carbon (13.7% Kyoto Reductions required by Annex 1 Countries)

Technologies:                National Renewable Technologies  Laboratory (NREL) and Oak Ridge  National  Laboratory (ORNL) have been separately developing energy and sequestration technologies for many years.

ORNL Conversion:            Using direct conversion of flue gas to NH4HCO3, mol wt: 79 would sequester this amount of carbon with 4.4 million metric tons of nitrogen.  This would be equal to 43% of the U.S. nitrogen consumption and probably not plausible in very large scale.

ORNL with Eprida/NREL:             Creating a carbon rich fertilizer combining two technologies.

This assumes using biomass to create a leverage of sequestration.  In this method, the biomass is used to create a sequestered carbon/char (20% by weight) carrier after removing hydrogen via the process demonstrated recently in a 50kg/hr experiment in Blakely GA with the NREL biomass to hydrogen technology. The hydrogen is then used to produce ammonia in industry standard methods. An advantage of a carbon carrier is that it allows for the creation of a slow release mechanism as a structural component of he carbon.  Additionally, it acts as a nutrient reservoir, storing essential nutrients in and around roots until soil concentrations drop.  This would reduce nitrate run-off and the detrimental effects they cause to streams, lakes and oceans. The positive aspects of increasing this type of carbon are in its early stages but over 2000 years ago man was creating highly productive soils by charring forests and rangeland. Research work on man-made Brazilian terra preta soils has shown as much as an 880% increase (Science, August 2002) in the second year plant productivity with the addition of char.  The characteristics of the char are important and research needs to be done to quantify differences in manufacture but the benefits are significant.

A slightly active char also provides for farm chemical runoff protection.  Research work at the University of North Carolina has shown that 200 pounds per acre could protect even sensitive crops from damage when sprayed with herbicides.  The binding activity provides the time necessary for chlorinated organics to break down naturally.  A controlled thermal process releases lower boiling point compounds and creates a terrestrial carbon reef at a microscopic level. These nanoscale structures provide safe haven to the microbes that facilitate fertile soil creation, while sequestering carbon for many hundred if not thousands of years.  The combination of these two forms of sequestration would also increase the growth rate and natural sequestration effort of growing plants.  According to research at Duke and University of Michigan, trees growing under the CO2 levels predicted for the future increase growth rates until reaching a plateau.  The limiting factor was reported to be available nutrients, specifically the depletion of available nitrogen by the rapidly growing trees. Efforts that sequester and measurably increase natural sequestration offer a potential method to leverage investments.    Proven increases in sequestration from land management practices is another way to achieve reduction targets.   

 Overview (10% Nitrogen) 

 

A typical 10% nitrogen composite fertilizer made from the sequestered carbon and integrated ammonium bicarbonate would have the following composition.

56.4% ammonium bicarbonate (AB)

43.6% char

This would equal carbon contents of:

8.6% from AB

34.9% from char (assuming 97% original carbon content)

Totaling            43.5% of ECOSS would be sequestered carbon. 

 

NOTE: A majority of the sequestration comes from biomass. A very positive consequence of this is that it reinforces the sustainable economic roles biomass and renewable resources will play in creating our future.  With more farming, and agriculture, we will expand the opportunities that our biosphere can offer.   

This sequestered carbon is very stable though research needs to be done to quantify tillage effects that could impact long-term storage. The above percentages can be adjusted to meet market demands and are a starting point for economic considerations.

Below are the breakdowns of component materials necessary to sequester the target 3.7 million tons of carbon for the 60 power plants.

  • 8.6 million  metric tons ECOSS (enriched carbon, organic slow-released sequestering fertilizer).

  • Containing 4.9 million tons of ammonium bicarbonate (or further processed into urea) with 0.86 million tons of nitrogen and representing 8.4% of the United States 2000 nitrogen consumption (USDA).  

  • 18.7 million tons of biomass would generate 1.3 million tons of hydrogen. Assuming a $40/ton delivered cost, (within a 40mile or 63km radius) the expense of raw materials would be $750 million.

  • Assuming 60 plant locations and biomass grown on non-essential or marginal farm land and producing 6 tons per acre (some energy crops average 13tons/acre) would require 1.62% of the 5024 sq miles to be planted in an biomass crop.  This would generate $12.5 million dollars in additional local farm income per plant.

  • 46,938 tons of additional sequestered carbon (+1.3%) would be required to offset the 172,105 tons of CO2 produced in collecting and hauling the approximately 43 truck loads of biomass to each power plant per day,. assuming a 63 km (40 mile) radius collection area and total annual fuel consumption of all vehicles of 16.9 million US gallons of diesel.

  • 307,000 tons of hydrogen is required to produce the ECOSS (enriched with ammonium bicarbonate or urea).  The value here is assumed to be that of a slower release nitrogen (at $100/ton), due in part to the imbedded nature of the nitrogen but also the soil fertility aspects provided by the carbon structure of ECOSS.   Additionally, with potassium and phosphorus combined, the material becomes a more commercially standard fertilizer, with a value of $860 million.

  • 1.004 million tons of hydrogen would remain which can be sold or used to produce power.   The value of this hydrogen at $1.00/kg would be $1.004 billion dollars.

  • $1.864 billion would be generated as gross income less operating and depreciation expense.

  • After deducting the costs of biomass plus $40/ton operational expense (NREL - rule of thumb for bio-processing facilities) a total before depreciation and taxes would be generated of $365 million.  

  • If a $10/ton CO2 credit were generated and sold equal to $137 million, cash flow would total $503 million.

  • With 60 facilities, this would equal $8.4 million per location.  If we assume that an investment with a 15% IRR and a 10 year total payback, this cash flow would purchase a $43.8 million dollar facility.  The real question is can a $43.8 million facility process $312,388 tons/yr producing 143,391 tons of ECOSS and 16,746 tons of hydrogen, for a total of 160,137 tons of total saleable products. For a quick reality check, an ammonia plant averages $374/ton/yr of capital cost of construction.  At this same price, this facility would equal $60 million and yield a 7% IRR on a 10 year ROI..  This makes a good reference point.  While not all of the plant capacity is a gas, and the first few plants would be more expensive, but as equipment became widely available and standardized, prices would quickly reach levels of acceptable profitability.  

The reality check seems to confirm that it is possible to profitably sequester carbon dioxide.   These are rough numbers attributed to US pricing guidelines.  Construction costs can vary greatly and where material, land and labor are less expensive, and fossil fuels are not readily available, this solution could prove very cost effective.

Click here for to view a spreadsheet analysis. (This is an interactive spreadsheet.  Change the variables and assumptions.)

(click here to download the excel file)