CO2 REDUCTION ALTERNATIVES

LET'S LOOK AT CO2 REDUCTION

First of all, this post is not an argument about human caused climate changes. It is intended to touch on the subject of the reduction of the amount of CO2 added to the atmosphere. This is also not an exhaustive study of reduction of CO2. Rather it provides my perspective of what we should be working on. Rather than just setting goals to be achieved in 15 or 30 years with new technology, it seeks to answer 3 questions

? Where does the human added CO2 come from?

? What reductions can be achieved with existing technology?

? What are the obstacles to implement the changes to achieve this reduction?

Currently the world-wide addition of CO2 to the atmosphere from human activities is?

43 BMT/year (Billion Metric Tons/year).?There have been multiple proposals on how to accomplish reductions in CO2. Some of these are:

? Eliminate fossil fuels by using renewable energy.

? Eliminate the Internal Combustion Engine with Electric Vehicles.?

? Convert coal power plants to natural gas.

? Use hydrogen as a fuel source since it does not generate CO2.

? Capture and sequester or use the CO2.

All of these proposals have generated wide discussions with advocates of each pointing out the advantages of their proposal. This has generated a whole host of new terminology – green hydrogen, blue hydrogen, grey hydrogen, black hydrogen, carbon taxes and net zero CO2. Again, the purpose of this post is not to define what these terms really mean

The purpose of the post is to present some calculations that I have made on some of these alternatives and to tabulate concerns about them. A summary of some of the potential reductions is as follows:

CO2 Reduction BMT/yr.

Convert Coal Power Plants to Gas

World Wide 8.1

US only 1.0

Convert Internal Combustion Engines to Battery Powered Electric Engines

World Wide 3.2

US only 0.8

Recover and Sequester 50% of CO2 Produced in Industrial Facilities and Power Plants

World Wide 2.3

Recover and Sequester 50% of CO2 Present in Natural Gas

World Wide 3.5

Recover and Hydrogenate the CO2 to Produce Methanol

World Wide 0.008

Let’s start off by looking at conversion of coal combustion to natural gas combustion. Of the total CO2 added to the atmosphere by human activities 14.7 BMT/year comes from coal combustion. When taking into account the composition of coal and natural gas and the differences in the heat of combustion, converting coal combustion to natural gas will reduce the amount of CO2 added to the atmosphere by 10.6 BMT/year. The fact that the conversion only in the US will only eliminate 10% of this illustrates the political difficulty of doing this on a worldwide basis. In addition to achieve the worldwide reduction, the natural gas capacity will have to increase by 100% and much of it would have to be as LNG to ship to areas where natural gas is not available.

The battery powered electrical vehicle has generated a lot of interest. However, as shown above even on a worldwide basis the CO2 reduction associated with conversion of all passenger vehicles to electric is only 30% of the coal conversion reduction. I have only considered the vehicle differences themselves and have not considered the mining, manufacturing of the vehicle or the production of electricity or gasoline. In making this comparison, I used an engine efficiency of 25% for the internal combustion engine and 99% for the electrical vehicle. Accomplishing this change on all passenger cars on a worldwide basis obviously has obstacles such as mineral availability, battery safety, higher initial cost and need for carbon tax.

Recovering and Sequestering CO2 whether from industrial/power plants or gas wells requires careful engineering and economic studies. The gas from either gas wells or industrial/power plant furnaces will be compressed to a pressure sufficiently high to recover the CO2. The CO2 must then be routed to an injection point to the underground formations. These underground formations have limited capacity and the pressure must be carefully monitored. This will require a network of piping and/or multiple injection points. Determining if the facilities are economically viable will depend on engineering studies of the facilities, geological studies of the planned underground formations and a method to provide an economic incentive for the necessary capital.

Recovering and using the CO2 to produce chemicals has also been suggested. As shown above, even if all the methanol produced in the world were produced by “green” hydrogenation of CO2, the reduction would not be significant.

What about hydrogen the “gold standard” as a fuel? Combustion of hydrogen does not produce CO2. If this hydrogen is produced by electrolysis with electricity produced by renewable power (wind or solar for example) the overall process will not generate any CO2. However, even in this very optimistic case, replacing natural gas with hydrogen likely will require significant new investment to transport it to the end user. Very approximate calculations indicate that transporting hydrogen relative to natural gas with all conditions remaining the same will require 3 times the compression energy at a 15% loss in pipeline capacity. The pipeline capacity is expressed in BTU/unit time to take into account the higher heating value of hydrogen. In addition, there are significant safety factors associated with hydrogen.?

In summary, the massive technical, political, business and economic effort required to make a significant reduction in CO2 added to the atmosphere by human sources reminds me of the WW II Manhattan Project and the development of the atomic bomb in 4 years. It can be done with focus, intensity, and strong leadership.?

In developing this post, I have used internet sources that I considered reliable and verified them where possible. I fully realize that not all that read this will agree with my calculations. I will be happy to share my calculations or discuss with anyone.?