Cost Analysis

 

Seabed Sequestration

The cost of seabed sequestration includes the cost, per tonne, to pump the CO2 into the seabed, and the cost to construct the necessary infrastructure to do so.  Past cost of sequestration per tonne of CO2 has varied widely.  For offshore saline formations in Australia, the upper bound per tonne was $30.20 per tonne, the median was $3.40, and the lower bound was $0.50.  Offshore formations in the North Sea varied from $12.00 for the upper bound, $7.70 for the median, and $4.70 for the lower bound (Benson & Cook 2005).  The average of the medians is $5.55 per tonne, while the overall average is $9.75.  In order to compute a conservative estimate of the cost, the value of $9.75 will be used in this analysis. 

According to our plan, 943 Gt of CO2 will be stored in the seabed over the one hundred year period.  This equates to 943,000,000,000 tonnes.  At $9.75 per tonne, it will cost $9.19 trillion dollars to sequester 943 Gt of carbon dioxide.

The cost of construction of the necessary infrastructure at each site, the capital investment cost, also varies.  The site at Sleipner, Norway cost $94 million, while the site at Snohvit, Norway cost $191 million (Benson & Cook 2005).  This averages to approximately $142.5 million per site.  Each site can sequester 4 Mt per year (Ghaderi, S. M., Keith, D. W., & Leonenko, Y. 2009). Our plan calls for sequestering 14.6 Gt of carbon dioxide per year in the seabed.  Therefore, 3650 sites must be constructed.  This will total, at $142.5 million per site, $520.125 billion.  Thus the overall total for seabed sequestration will be $9.71 trillion.

Terrestrial Aquifers

The overall cost of terrestrial aquifer sequestration includes the cost per tonne of carbon dioxide captured and the capital cost of building an injection plant at each site.  The cost per tonne of carbon dioxide is estimated to be in the range of $0.60-$8.30 per tonne of carbon dioxide (IPCC 2005). This middle of this range is $4.45 per tonne, which will be used in this cost analysis.  Saline aquifers, according to our plan, will sequester 943 Gt of carbon dioxide.  Therefore, it will cost $4.2 trillion to sequester 943 Gt of carbon dioxide at $4.45 per tonne.

An injection station in Sleipner, Norway cost $95.9 million to build, with maintenance costs of $7 million a year (Torp et al, 2005).  However, four stations in China only cost $56-$71 million to build with operating and maintenance costs at $13-$18 million per year (Meng et al. 2006).  For the purposes of this estimate, the average values of $70 million per station and $9 million for maintenance will be used.  The reason for the low average for maintenance is because the figure for the stations in China are based off of maintenance and operating costs, while our calculation is only analyzing maintenance costs for this portion. 

Each site can sequester 4 Mt per year (Ghaderi et al. 2009).  Our plan calls for sequestering 14.6 Gt of carbon dioxide per year in saline aquifers.  Therefore, 3650 sites must be constructed.  This will total, at $70 million per site, to $255.5 billion.  The maintenance costs of 3650 stations, at $9 million a station per year, for seventy-eight years (Phases II and III of our plan) is $2.56 trillion. 

The total cost for saline aquifer sequestration, adding sequestration cost with construction costs and site maintenance costs, is $7.02 trillion.

In Situ Mineral Sequestration

For in situ mineral sequestration, the capital cost, operating cost, and maintenance cost are all included in the overall cost per metric tonne carbon dioxide.  In situ is one of the least tested and developed of these methods, so costs are still rough estimates.  It is estimated that, once fully developed and tested, in situ mineral sequestration will cost less than $10 per tonne sequestered (Lackner 2003).  CarbFix’s pilot project has sequestered 2,000 tonnes carbon dioxide at the cost of $11 million, at a cost of $5,500 per tonne (The Earth Institute at Columbia University 2009).  However, this is still a pilot program and costs are far higher than they would be once in situ is implemented on an industrial scale.  For the purposes of this cost analysis, we estimated a conservative cost of $17.50 per tonne of carbon dioxide, nearly double Lackner’s assessment but still far less than the per tonne cost of CarbFix’s pilot program.  In our plan, in situ mineral sequestration will sequester 350 Gt of carbon dioxide.  At $17.50 per tonne, the total cost for sequestering 350 Gt of carbon dioxide will be $6.125 trillion.

Enhanced Oil Recovery/Enhanced Gas Recovery

The cost for CO2-enhanced oil recovery/enhanced gas recovery is calculated by barrels of oil.  The capital and operations and maintenance cost is $3.50 per barrel of oil or gas produced (Plasynski 2008).  The average amount of carbon dioxide that can be injection is 6.0 Megacubic-feet (Mcf) per barrel (Stevens, S. H., Kuuskraa, V. A., Gale, J., & Beecy, D. 2001). Approximately 90% of carbon dioxide pumped into all reservoirs for oil extraction is sequestered; thus 5.4 Mcf of carbon dioxide is sequestered per barrel of oil (Stevens et al. 2001).  According to past enhanced oil recovery projects projects in the Permian Basin in the United States, about 1674 Bcf is equivalent to 0.09 Gt of carbon dioxide.  This equates 5.38x10-8 Gt carbon dioxide to one Mcf carbon dioxide.  Since 5.4 Mcf is sequestered per barrel of oil produced, 2.91x10-7 Gt of carbon dioxide is stored per barrel.  The cost is $3.50 per barrel, the cost per Gt of carbon dioxide stored is thus $12 million.  According to our plan, enhanced oil recovery will store 314 Gt of carbon dioxide.  The total cost would thus be $3.768 billion dollars.

Air Capture

The overall cost of air capture includes the cost per tonne of carbon dioxide captured and the capital cost of building each air capture plant.  It costs $136 per metric ton of carbon dioxide captured via air capture.  A single plant with a tower diameter of 110 meters with 50% capture efficiency costs $12 million with yearly operational and maintenance costs of $400,000 a year.   Each plant can capture 279,000 tonnes of carbon dioxide a year (Keith et al. 2005).  At $136 per tonne of carbon dioxide, it will cost $37.944 million per year to capture the carbon dioxide.  Including operational and maintenance costs, it will cost $38.344 million per year to operate one plant. 

According to our plan (please see Modeling, Scenario Three), approximately 86655 air capture plants will be needed to capture the 1560 Gt of carbon dioxide necessary to lower the atmospheric concentration of carbon dioxide back to 350 ppm at the end of our one hundred year plan.  At $12 million per plant, this comes to a total of $1.04 trillion to construct 86655 plants. 

Our plan calls for these plants to operate at full capacity for seventy-eight years (Phases II and III).  The cost of running 86655 plants for 78 years at $38.944 million per year per plant is $263.226 trillion dollars.  Including the cost to construct the 86655 plants, the total cost of air capture, estimated conservatively, over the seventy-eight year period is $264.266 trillion dollars. 

Alternative Energies

Over the one hundred years, our plan calls for renewable energy to account for or eliminate the emissions of 1770 Gt of carbon dioxide.  Thus, renewable and alternative energies have to produce the equivalent amount of energy that would have been created by carbon-emitting fossil fuels for this amount of carbon dioxide.  We use a variety of alternative energies to replace fossil fuels.  

For every kiloWatthour (kWH), a coal-fired power plant produces 996 grams of carbon dioxide (University of Strathclyde 2002).  996 grams is 9.96x10-4 tonnes.  Therefore, dividing the total number of tonnes that must be eliminated by alternatives and this value, we find that we must produce 1.777x1015 kWH of electricity by alternative energy sources.  The breakdown of how much each form of alternative energy will cover is as follows:

Technology

Capital cost/ kw ($)

Kwh cost (running) ($)

Percentage (%)

 

Solar

372

0.25

15

 

Tidal

590.5

0.11

20

 

Nuclear

245.75

0.042

15

 

Wind

142

0.05

30

 

Geothermal

222.01

0.1

10

 

Coal

negligible

0.053

10

 

 

A more detailed explanation for how these numbers were calculated can be found in the explanation for the model.  The total calculated cost is $180 trillion.

Forestry

There are three forms of forestry management that our plan implements: agroforestry, afforestry, and reforestation.  In total, our plan calls for forestry management to sequester 600 Gt of carbon dioxide.

Afforestation and reforestation can together sequester approximately 264 Gt carbon dioxide at a cost of $27.32 per tonne (Sohngen, B, & Sedjo, R., 2004). This equates to a total cost of afforestation and reforestation at $7.2 trillion.

Agroforestry therefore must sequester 336 Gt of carbon dioxide.  Agroforestry costs $0.36-$0.66 per tonne of carbon dioxide sequestered (Dixon, R.K., K.J. Andrasko, F.A. Sussman, M.A. Lavinson, M.C. Trexler and T.S. Vinson, 1993).  This average is $0.51 per tonne of carbon dioxide, which will be used in this analysis.  To sequester 336 Gt of carbon dioxide at $0.51 per tonne, the total cost of agroforestry will be $171.4 billion.

Thus the total cost of forestry management to store 600 Gt of carbon dioxide is $7.37 trillion dollars.

Point Source

Point source is implemented in our plan to reduce and then eliminate the carbon dioxide emissions from every coal-fired power plant in the world.  In order to calculate the total cost of our plan we first calculated the cost to implement point source in the United States and then scaled that to fit the entire world. 

The plan for point source involves retrofitting every plant that is capable of being retrofitted with post-combustion technology and then completely rebuilding the older plants and integrating post-combustion capture into the construction.  There are 1522 coal-fired plants in the United States (Simbeck, D., & Roekpooritat, W.  2009). It is estimated that 59% of these plants can be retrofitted (Massachusetts Institute of Technology 2009).  The cost of retrofitting a plant is $528 million (Simbeck, D. 2009). Therefore, if 59% of 1522 plants can be retrofitted, at a cost of $528 million per plant, then the cost of retrofitting plants will be $474.13 billion.  The additional 41% of plants that cannot be retrofitted will be rebuilt at $1.795 billion per plant.  This equates to $1.12 trillion to rebuild these plants.  Therefore, the total cost of implementing point source capture on coal-fired plants in the United States is about $1.59 trillion.

The total carbon dioxide emissions in the United States due to coal-fired power plants is 1.992 Gt (International Energy Agency 2009).  To create a scaling factor to use to evaluate the cost of the implementation of point source internationally, we divided the total cost of implementation in the United States by the total emissions of the United States, which is $0.793 trillion/Gt.  The international coal-fired carbon dioxide emissions is 7.859 Gt (Internal Energy Agency 2009).  This number multiplied by our scaling factor gives a total implementation cost of $6.27 trillion for coal-fired power plants.

However, carbon dioxide emissions from coal-fired power plants only constitute 40% of all electricity generation, and electricity generation itself only constitutes 32% of all international carbon dioxide emissions (Department of Energy 2000).  Furthermore, only 50% of all international carbon dioxide emissions can be captured via point source (Mahmoudkhani  et al. 2009).  Extrapolating the $6.27 trillion value for coal-fired plants to reflect all 50% of emissions that can be captured, the total cost of point source capture can be estimated to $24.50 trillion.

The running cost was estimated using an equation that modeled the total yearly energy produced by coal-fired power plants.  This total came to be $469.5 billion.

Additionally a sufficient point-source research and development effort requires $1 billion per year for at least a decade (Massachusetts Institute of Technology 2009).  Therefore, an additional $10 billion must be added to the total. 

The complete cost is therefore $24.97 trillion.

Transportation

For purposes of this study, we will estimate an average of 30 inch diameter piping for the pipelines used across the world. Since the Cortez pipeline transports 0.0193 Gt of carbon dioxide per year, we can estimate the number of “Cortez” pipelines required to transport the 6.0 Gt of carbon dioxide emitted by the entire United States, by simply dividing (Doctor, 2005). If we were to construct 311 of these pipeline models throughout the US, we will construct about 251,000 km of pipeline for the entire United States. This is a conservative estimate because many coal-fired power plants are located on or near the sequestration sites.   Since the United States is accountable for 20% of the world’s emissions, we multiplied the total length of carbon dioxide pipeline in the United States by a factor of 5 to get the total distance of pipeline required for the world (Source 9, 2009). This results in a total pipeline length of 1,255,600 km of 30 inch diameter pipeline for the world.  The cost to construct one km of a 30 inch diameter pipeline is $600,000 (Doctor, 2005; Moritis, 2001; Herzog, 2005). This totals to approximately $753.6 billion for pipeline construction.

Additionally, the operation and maintenance costs are $3,250 per km per year and an average cost of $1160 per Gt of carbon dioxide per year transported to storage sites (McCoy 2008).  Therefore, yearly costs for transport, not including costs due to sequestration, consist of $4.08 billion for operation and maintenance and $34.8 billion for transport, for a total of $38.88 billion.  Assuming full production for seventy-five years, the operational costs are $2.916 trillion.  Therefore, the total cost for transportation is $3.67 trillion. 

Research and Development: Biochar and Ex Situ

Allocating $10 million a year for the purposes of research and development for fifty years, the total cost of research and development for Biochar and Ex Situ mineral sequestration will be $500 million.

Technology

Cost (trillion $)

Adjusted Cost1 (trillion $)

 

Seabed

9.71

9.71

 

Saline Aquifer

7.02

7.02

 

In Situ Mineral

6.125

6.125

 

CO2-enhanced oil recovery/ enhanced gas recovery

3.768x10-3

3.768x10-3

 

Air Capture

264.266

69.5

 

Alternative Energies

180.

180.

 

Forestry

7.37

7.37

 

Point Source

24.97

24.97

 

Transportation

3.67

3.67

 

Research and Development

5.0x10-4

5.0x10-4

 

TOTAL

503.1

308.4