The Why and How of Carbon Capture and Sequestration

Carbon capture and sequestration (CCS) is becoming newsworthy again as the EPA’s clean power proposal is being contested in the court system.

The Wall Street Journal ran an article this week on CCS, but covered less than half the story. This is typical of the media, but the Wall Street Journal should know better.

CCS is seen as a way to cut CO2 emissions 80% to prevent a climate catastrophe.

Two steps are involved in the CCS process. The first step was not covered by the Wall Street Journal.

  1. CO2 from the burning of coal or natural gas is captured during the burning process or from the waste stream after burning has taken place. Alternatively, it is heated to form a synthetic gas from which the CO2 can be extracted.
  2. Captured CO2 is then compressed into a liquid, transported by pipeline to a geologic formation where the liquid CO2 can be injected into the ground and to the geologic formation where the CO2 can be entrapped.

Capturing CO2

Experiments have been conducted for capturing CO2 before, during and after combustion.

Integrated gasification combined cycle (IGCC) power plants cook the coal to form a synthetic gas from which the CO2 can be extracted, allowing the remaining gases, mostly hydrogen, to be burned in a gas turbine to generate electricity.

The coal industry has touted this process as clean coal. Unfortunately, after three such units have been built in the United States, their cost has been shown to be exorbitant at over $6,000 per KW, or about what it costs to build a new nuclear power plant.

Experiments have been done for capturing CO2 while coal is burned in a coal-fired power plant.

Experiments have also been done to capture CO2 from the waste stream of both coal-fired and natural gas power plants.

These experiments have demonstrated that coal-fired power plants must be derated by approximately 30% due to the parasitic loads required for capturing and liquefying the CO2. This means a coal-fired power plant with a rating of 300 MW is converted into a power plant rated 210 MW. In other words, 30% of the electricity generated by the coal-fired power plant is used to capture and compress the CO2.

Natural gas power plants will need to be derated by more than 30% because the waste steam includes less CO2, making it more difficult to capture CO2.

The end result is that a new power plant needs to be built every time three power plants are equipped to capture CO2, to replace the electricity lost from capturing CO2.

One can conclude that it’s possible to capture CO2 from coal-fired and natural gas power plants, but that the cost will be very high.

Sequestration

The captured CO2 must be disposed of underground. This involves transporting the liquid CO2 under high pressures, approximately 2.000 psi, to where it can be disposed of underground. This also was not covered by the Wall Street Journal article.

Transporting CO2 will involve building a series of 24 inch, or larger, pipelines across the United States to transport the liquid CO2 from approximately 400 coal-fired power plants. Additional pipelines would be required for natural gas power plants. The Pacific National Laboratory published a paper concluding that between 11,000 and 23,000 miles of new pipelines would have to be built.

These maps show where pipelines might be located in the United States and Europe.

USA CO2 Pipelines
USA CO2 Pipelines

 

EU CO2 Pipelines 2050
EU CO2 Pipelines 2050

Once transported to where it might be sequestered, the CO2 must be injected under ground into an appropriate geologic formation.

Carbon Sequestration Atlas of the United States and Canada
Carbon Sequestration Atlas of the United States and Canada

An atlas has been compiled of potential sites for sequestering CO2. While there are a few examples of where CO2 has been sequestered, e.g., the Sleipner gas field in Norway, Salah in Algeria and in Alberta Canada, none have involved the quantities of CO2 that would have to be sequestered if there was a serious effort to use CCS.

Currently, the largest underground sequestration operation is the Sleipner gas field where one million metric tons of CO2 are injected annually into the saline aquifer under the North Sea.

This compares with 1,800,000,000 metric tons, or 1,800 times the amount sequestered in the Sleipner gas field. This is the amount of CO2 that would have to be sequestered every year if 80% of the CO2 from U.S. power plants were to be captured and sequestered.

Not only is the quantity staggering, but there is no certainty that the CO2 would remain underground for the thousands of years needed to prevent a climate catastrophe, if the CO2 hypothesis is correct.

Other unresolved issues include:

  • Ownership of geologic formations
  • Legal liability if CO2 escapes or causes harm
  • Whether injecting liquid CO2 underground would cause earthquakes

The massive costs associated with CCS, and the uncertainty that the CO2 would remain sequestered underground for centuries leads to the conclusion that CCS is unrealistic.

* * * * * *

NOTE:

It’s easy to subscribe to articles by Donn Dears.

Go to the photo on the right side of the article where it says email subscription. Click and enter your email address. You can unsubscribe at any time.

If you know people who would be interested in these articles please send them a link to the article and suggest they also subscribe.

© Power For USA, 2010 – 2015. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author, Donn Dears LLC, is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Power For USA with appropriate and specific direction to the original content.

0 Replies to “The Why and How of Carbon Capture and Sequestration”

  1. Hi Donn,

    It would take 2 300MW plants to supply 600MW without CCS and 3 300MW plants with CSS – although the 3 would generate 610MW.

    Regards,

    Steve

    • Thanks for the comment. Three 300 MW plants equal a total of 900 MW. If the three are converted to carbon capture each would be rated 210 MW, so three such units would total 630 mw. This requires the addition of a new 300 MW plant that’s carbon capture equipped and rerated as 210 MW, bringing the total MW to 840 for four such plants.
      I think we are both arriving at essentially the same conclusion.

  2. Donn,

    I found that article fascinating, especially your question about what happens to the environment if billions of tons of carbon dioxide somehow rapidly leaks out.

    That would even be worse than Wiki-leaks!

    Craig

    Sent from my iPhone

    >

  3. Are they serious? Do they have any idea what they are playing with? Read about Lake Nyos

    – On August 21, 1986, possibly as the result of a landslide, Lake Nyos suddenly emitted a large cloud of CO2, which suffocated 1,700 people and 3,500 livestock in nearby towns and villages.[2][3] Though not completely unprecedented, it was the first known large-scale asphyxiation caused by a natural event. http://en.wikipedia.org/wiki/Lake_Nyos for more or Google It.

    Look at the number of farm owners against Keystone XL – and its dangers/hazards are minuscule compared to the transportation of CO2 in a pipe of the needed size and pressure. At least Natural gas Burns and goes away. Even if moved by Rail, Truck, or Barge the same problems exist. Have they any idea of the volume of CO2 that need to be moved? The volume of CO2 would be more then twice the volume of the coal burned! IF shipped as ICE. Take the Power generated for the power plants involved. Convert the output to needed gallons of oil to make that power, multiply by two. The number is staggering! Think of the manpower to build this! Think of the route the pipelines would have to take to avoid population centers. Then think of the consequence a failure. There will be one predictable effect – elimination of massive quantities of human life. Is that the ultimate desire?

    They are even talking about using CO2 in air conditioners! Another moronic idea. In addition to the fire alarm, CO alarm you will need a CO2 alarm so that when you go to sleep and the AC evaporator coil develops a leak, you have a chance of waking up. CO2 and H20 makes a fairly good acid which will quickly eat through copper pipe. Only takes a very small amount in a low spot.

    • Thanks. Great comment. The reference to refrigerators reminded me of what happened when growing up in New York City.
      At the time, ammonia was used as a refrigerant. A refrigerator leaked in another apartment and it was necessary to evacuate the building because of the ammonia fumes. At least ammonia is an irritant, while CO2 is colorless and odorless.

  4. Pingback: Weekly Climate and Energy News Roundup #179 | Watts Up With That?

Leave a Reply

Your email address will not be published. Required fields are marked *

*